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Polyamine biosynthesis impacts cellular folate requirements necessary to maintain S-adenosylmethionine and nucleotide pools  

PubMed Central

Folate (vitamin B9) is utilized for synthesis of both S-adenosylmethionine (AdoMet) and deoxythymidine monophosphate (dTMP), which are required for methylation reactions and DNA synthesis, respectively. Folate depletion leads to an imbalance in both AdoMet and nucleotide pools, causing epigenetic and genetic damage capable of initiating tumorigenesis. Polyamine biosynthesis also utilizes AdoMet, but polyamine pools are not reduced under a regimen of folate depletion. We hypothesized that high polyamine biosynthesis, due to the high demand on AdoMet pools, might be a factor in determining sensitivity to folate depletion. We found a significant correlation (P<0.001) between polyamine biosynthesis and the amount of folate required to sustain cell line proliferation. We manipulated polyamine biosynthesis by genetic and pharmacological intervention and mechanistically demonstrated that we could thereby alter AdoMet pools and increase or decrease demand on folate availability needed to sustain cellular proliferation. Furthermore, growing a panel of cell lines with 100 nM folate led to imbalanced nucleotide and AdoMet pools only in cells with endogenously high polyamine biosynthesis. These data demonstrate that polyamine biosynthesis is a critical factor in determining sensitivity to folate depletion and may be particularly important in the prostate, where biosynthesis of polyamines is characteristically high due to its secretory function.—Bistulfi, G., Diegelman, P., Foster, B. A., Kramer, D. L., Porter, C. W., Smiraglia, D. J. Polyamine biosynthesis impacts cellular folate requirements necessary to maintain S-adenosylmethionine and nucleotide pools. PMID:19417083

Bistulfi, G.; Diegelman, P.; Foster, B. A.; Kramer, D. L.; Porter, C. W.; Smiraglia, D. J.



Rice folate enhancement through metabolic engineering has an impact on rice seed metabolism, but does not affect the expression of the endogenous folate biosynthesis genes.  


Folates are key-players in one-carbon metabolism in all organisms. However, only micro-organisms and plants are able to synthesize folates de novo and humans rely entirely on their diet as a sole folate source. As a consequence, folate deficiency is a global problem. Although different strategies are currently implemented to fight folate deficiency, up until now, all of them have their own drawbacks. As an alternative and complementary means to those classical strategies, folate biofortification of rice by metabolic engineering was successfully achieved a couple of years ago. To gain more insight into folate biosynthesis regulation and the effect of folate enhancement on general rice seed metabolism, a transcriptomic study was conducted in developing transgenic rice seeds, overexpressing 2 genes of the folate biosynthetic pathway. Upon folate enhancement, the expression of 235 genes was significantly altered. Here, we show that rice folate biofortification has an important effect on folate dependent, seed developmental and plant stress response/defense processes, but does not affect the expression of the endogenous folate biosynthesis genes. PMID:23771598

Blancquaert, Dieter; Van Daele, Jeroen; Storozhenko, Sergei; Stove, Christophe; Lambert, Willy; Van Der Straeten, Dominique



Characterization of the Role of para-Aminobenzoic Acid Biosynthesis in Folate Production by Lactococcus lactis?  

PubMed Central

The pab genes for para-aminobenzoic acid (pABA) biosynthesis in Lactococcus lactis were identified and characterized. In L. lactis NZ9000, only two of the three genes needed for pABA production were initially found. No gene coding for 4-amino-4-deoxychorismate lyase (pabC) was initially annotated, but detailed analysis revealed that pabC was fused with the 3? end of the gene coding for chorismate synthetase component II (pabB). Therefore, we hypothesize that all three enzyme activities needed for pABA production are present in L. lactis, allowing for the production of pABA. Indeed, the overexpression of the pABA gene cluster in L. lactis resulted in elevated pABA pools, demonstrating that the genes are involved in the biosynthesis of pABA. Moreover, a pABA knockout (KO) strain lacking pabA and pabBC was constructed and shown to be unable to produce folate when cultivated in the absence of pABA. This KO strain was unable to grow in chemically defined medium lacking glycine, serine, nucleobases/nucleosides, and pABA. The addition of the purine guanine, adenine, xanthine, or inosine restored growth but not the production of folate. This suggests that, in the presence of purines, folate is not essential for the growth of L. lactis. It also shows that folate is not strictly required for the pyrimidine biosynthesis pathway. L. lactis strain NZ7024, overexpressing both the folate and pABA gene clusters, was found to produce 2.7 mg of folate/liter per optical density unit at 600 nm when the strain was grown on chemically defined medium without pABA. This is in sharp contrast to L. lactis strains overexpressing only one of the two gene clusters. Therefore, we conclude that elevated folate levels can be obtained only by the overexpression of folate combined with the overexpression of the pABA biosynthesis gene cluster, suggesting the need for a balanced carbon flux through the folate and pABA biosynthesis pathway in the wild-type strain. PMID:17308179

Wegkamp, Arno; van Oorschot, Wietske; de Vos, Willem M.; Smid, Eddy J.



Shmt1 and de novo thymidylate biosynthesis underlie folate-responsive neural tube defects in mice1234  

PubMed Central

Background: Folic acid supplementation prevents the occurrence and recurrence of neural tube defects (NTDs), but the causal metabolic pathways underlying folic acid–responsive NTDs have not been established. Serine hydroxymethyltransferase (SHMT1) partitions folate-derived one-carbon units to thymidylate biosynthesis at the expense of cellular methylation, and therefore SHMT1-deficient mice are a model to investigate the metabolic origin of folate-associated pathologies. Objectives: We examined whether genetic disruption of the Shmt1 gene in mice induces NTDs in response to maternal folate and choline deficiency and whether a corresponding disruption in de novo thymidylate biosynthesis underlies NTD pathogenesis. Design: Shmt1 wild-type, +/?, and ?/? mice fed either folate- and choline-sufficient or folate- and choline-deficient diets were bred, and litters were examined for the presence of NTDs. Biomarkers of impaired folate metabolism were measured in the dams. In addition, the effect of Shmt1 disruption on NTD incidence was investigated in Sp mice, an established folate-responsive NTD mouse model. Results: +/? and ?/? embryos exhibited exencephaly in response to maternal folate and choline deficiency. Shmt1 disruption on the Sp background exacerbated NTD frequency and severity. Pax3 disruption impaired de novo thymidylate and purine biosynthesis and altered amounts of SHMT1 and thymidylate synthase protein. Conclusions: SHMT1 is the only folate-metabolizing enzyme that has been shown to affect neural tube closure in mice by directly inhibiting folate metabolism. These results provide evidence that disruption of Shmt1 expression causes NTDs by impairing thymidylate biosynthesis and shows that changes in the expression of genes that encode folate-dependent enzymes may be key determinates of NTD risk. PMID:21346092

Beaudin, Anna E; Abarinov, Elena V; Noden, Drew M; Perry, Cheryll A; Chu, Stephanie; Stabler, Sally P; Allen, Robert H



Complex Patterns of Gene Fission in the Eukaryotic Folate Biosynthesis Pathway  

PubMed Central

Shared derived genomic characters can be useful for polarizing phylogenetic relationships, for example, gene fusions have been used to identify deep-branching relationships in the eukaryotes. Here, we report the evolutionary analysis of a three-gene fusion of folB, folK, and folP, which encode enzymes that catalyze consecutive steps in de novo folate biosynthesis. The folK-folP fusion was found across the eukaryotes and a sparse collection of prokaryotes. This suggests an ancient derivation with a number of gene losses in the eukaryotes potentially as a consequence of adaptation to heterotrophic lifestyles. In contrast, the folB-folK-folP gene is specific to a mosaic collection of Amorphea taxa (a group encompassing: Amoebozoa, Apusomonadida, Breviatea, and Opisthokonta). Next, we investigated the stability of this character. We identified numerous gene losses and a total of nine gene fission events, either by break up of an open reading frame (four events identified) or loss of a component domain (five events identified). This indicates that this three gene fusion is highly labile. These data are consistent with a growing body of data indicating gene fission events occur at high relative rates. Accounting for these sources of homoplasy, our data suggest that the folB-folK-folP gene fusion was present in the last common ancestor of Amoebozoa and Opisthokonta but absent in the Metazoa including the human genome. Comparative genomic data of these genes provides an important resource for designing therapeutic strategies targeting the de novo folate biosynthesis pathway of a variety of eukaryotic pathogens such as Acanthamoeba castellanii. PMID:25252772

Maguire, Finlay; Henriquez, Fiona L.; Leonard, Guy; Dacks, Joel B.; Brown, Matthew W.; Richards, Thomas A.



Complex patterns of gene fission in the eukaryotic folate biosynthesis pathway.  


Shared derived genomic characters can be useful for polarizing phylogenetic relationships, for example, gene fusions have been used to identify deep-branching relationships in the eukaryotes. Here, we report the evolutionary analysis of a three-gene fusion of folB, folK, and folP, which encode enzymes that catalyze consecutive steps in de novo folate biosynthesis. The folK-folP fusion was found across the eukaryotes and a sparse collection of prokaryotes. This suggests an ancient derivation with a number of gene losses in the eukaryotes potentially as a consequence of adaptation to heterotrophic lifestyles. In contrast, the folB-folK-folP gene is specific to a mosaic collection of Amorphea taxa (a group encompassing: Amoebozoa, Apusomonadida, Breviatea, and Opisthokonta). Next, we investigated the stability of this character. We identified numerous gene losses and a total of nine gene fission events, either by break up of an open reading frame (four events identified) or loss of a component domain (five events identified). This indicates that this three gene fusion is highly labile. These data are consistent with a growing body of data indicating gene fission events occur at high relative rates. Accounting for these sources of homoplasy, our data suggest that the folB-folK-folP gene fusion was present in the last common ancestor of Amoebozoa and Opisthokonta but absent in the Metazoa including the human genome. Comparative genomic data of these genes provides an important resource for designing therapeutic strategies targeting the de novo folate biosynthesis pathway of a variety of eukaryotic pathogens such as Acanthamoeba castellanii. PMID:25252772

Maguire, Finlay; Henriquez, Fiona L; Leonard, Guy; Dacks, Joel B; Brown, Matthew W; Richards, Thomas A



Structure-Based Design and Development of Functionalized Mercaptoguanine Derivatives as Inhibitors of the Folate Biosynthesis Pathway Enzyme 6-Hydroxymethyl-7,8-dihydropterin Pyrophosphokinase from Staphylococcus aureus.  


6-Hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK), an enzyme from the folate biosynthesis pathway, catalyzes the pyrophosphoryl transfer from ATP to 6-hydroxymethyl-7,8-dihydropterin and is a yet-to-be-drugged antimicrobial target. Building on our previous discovery that 8-mercaptoguanine (8MG) is an inhibitor of Staphylococcus aureus HPPK (SaHPPK), we have identified and characterized the binding of an S8-functionalized derivative (3). X-ray structures of both the SaHPPK/3/cofactor analogue ternary and the SaHPPK/cofactor analogue binary complexes have provided insight into cofactor recognition and key residues that move over 30 Å upon binding of 3, whereas NMR measurements reveal a partially plastic ternary complex active site. Synthesis and binding analysis of a set of analogues of 3 have identified an advanced new lead compound (11) displaying >20-fold higher affinity for SaHPPK than 8MG. A number of these exhibited low micromolar affinity for dihydropteroate synthase (DHPS), the adjacent, downstream enzyme to HPPK, and may thus represent promising new leads to bienzyme inhibitors. PMID:25357262

Dennis, Matthew L; Chhabra, Sandeep; Wang, Zhong-Chang; Debono, Aaron; Dolezal, Olan; Newman, Janet; Pitcher, Noel P; Rahmani, Raphael; Cleary, Ben; Barlow, Nicholas; Hattarki, Meghan; Graham, Bim; Peat, Thomas S; Baell, Jonathan B; Swarbrick, James D



Folate-deficiency anemia  


Folate-deficiency anemia is a decrease in red blood cells ( anemia ) due to a lack of folate. Folate is a type ... B vitamin. It is also called folic acid. Anemia is a condition in which the body does ...


Isotope Ratio-Based Profiling of Microbial Folates  

PubMed Central

Folate metabolism, which is responsible for one-carbon transfer reactions in critical cellular processes including thymidine biosynthesis, is among the most important targets of antibiotic and anticancer drugs. Analysis of intracellular folates is complicated by three different types of folate modification: oxidation/reduction, methylation, and polyglutamylation. Here we present a method for quantifying the full diversity of intracellular folates by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The method begins with folate extraction using ?75°C methanol:water, with ascorbic acid and ammonium acetate added to prevent folate interconversion. The extract is then separated using hydrophilic interaction chromatography with an amino column, ionized by positive mode electrospray, and analyzed on a triple quadrupole instrument using multiple reaction monitoring. The method has been used to profile the folate pools in Escherichia coli and Saccharomyces cerevisiae, with absolute levels of selected folates in E. coli measured by spiking extracts of cells fed uniformly 13C-glucose with purified, unlabeled folate standards. An isotope-ratio-based approach has been applied to study the effects of trimethoprim, a clinically important antibiotic that blocks bacterial dihydrofolate reductase. In addition to causing the expected increase in oxidized and decrease in reduced folates, trimethoprim triggered a dramatic and previously unrecognized shift towards shorter polyglutamate chain lengths. This finding highlights the potential for analysis of the full spectrum of cellular folates by MS/MS to unveil novel biological phenomena. PMID:17360194

Lu, Wenyun; Kwon, Yun Kyung



Synthesis and biological activity of a novel series of 6-substituted thieno[2,3-d]pyrimidine antifolate inhibitors of purine biosynthesis with selectivity for high affinity folate receptors over the reduced folate carrier and proton-coupled folate transporter for cellular entry  

PubMed Central

A series of seven 2-amino-4-oxo-6-substituted thieno[2,3-d]pyrimidines, with bridge length variations (from 2-8 carbon atoms) were synthesized as selective folate receptor (FR) ? and ? substrates and as antitumor agents. The syntheses were accomplished from appropriate allylalcohols and 4-iodobenzoate to afford the aldehydes which were converted to the appropriate 2-amino-4-carbethoxy-5-substituted thiophenes 23-29. Cyclization with chlorformamidine afforded the thieno[2,3-d]pyrimidines 30-36 which were hydrolyzed and coupled with diethyl-L-glutamate, followed by saponification to give the target compounds 2-8. Compounds 3-6 were potent growth inhibitors (IC50 4.7 to 334 nM) of human tumor cells (KB and IGROV1) that express FRs. In addition, compounds 3-6 inhibited the growth of Chinese hamster ovary (CHO) cells that expressed FRs but not the reduced folate carrier (RFC) or proton-coupled folate transporter (PCFT). However, the compounds were inactive toward CHO cells that lacked FRs but contained either the RFC or PCFT. By nucleoside and 5-amino-4-imidazole carboxamide (AICA) protection studies, along with in vitro and in situ enzyme activity assays, the mechanism of antitumor activity was identified as the dual inhibition of glycinamide ribonucleotide formyltransferase and, likely, AICA ribonucleotide formyltransferase. The dual inhibitory activity of the active thieno[2,3-d]pyrimidine antifolates and the FR specificity represent unique mechanistic features for these compounds distinct from all other known antifolates. The potent inhibitory effects of compounds 3-6 toward cells expressing FRs but not PCFT provide direct evidence that cellular uptake of this series of compounds by FRs does not depend on the presence of PCFT and argues that direct coupling between these transporters is not obligatory. PMID:19371039

Deng, Yijun; Zhou, Xilin; Desmoulin, Sita Kugel; Wu, Jianmei; Cherian, Christina; Hou, Zhanjun; Matherly, Larry H.; Gangjee, Aleem



Cerebral Folate Deficiency  

ERIC Educational Resources Information Center

Cerebral folate deficiency (CFD) is associated with low levels of 5-methyltetrahydrofolate in the cerebrospinal fluid (CSF) with normal folate levels in the plasma and red blood cells. The onset of symptoms caused by the deficiency of folates in the brain is at around 4 to 6 months of age. This is followed by delayed development, with deceleration…

Gordon, Neil



Human Folate Bioavailability  

PubMed Central

The vitamin folate is recognized as beneficial health-wise in the prevention of neural tube defects, anemia, cardiovascular diseases, poor cognitive performance, and some forms of cancer. However, suboptimal dietary folate intake has been reported in a number of countries. Several national health authorities have therefore introduced mandatory food fortification with synthetic folic acid, which is considered a convenient fortificant, being cost-efficient in production, more stable than natural food folate, and superior in terms of bioavailability and bioefficacy. Other countries have decided against fortification due to the ambiguous role of synthetic folic acid regarding promotion of subclinical cancers and other adverse health effects. This paper reviews recent studies on folate bioavailability after intervention with folate from food. Our conclusions were that limited folate bioavailability data are available for vegetables, fruits, cereal products, and fortified foods, and that it is difficult to evaluate the bioavailability of food folate or whether intervention with food folate improves folate status. We recommend revising the classical approach of using folic acid as a reference dose for estimating the plasma kinetics and relative bioavailability of food folate. PMID:22254106

Ohrvik, Veronica E.; Witthoft, Cornelia M.



Genes of folate biosynthesis in wheat  

Microsoft Academic Search

Micronutrient deficiency is preventing an estimated one-third of the world's population from reaching their physical and intellectual potential. This results in reduced education attainment and work productivity which negatively impacts on regional development and economies. Contributing to the aetiology of these deficiencies is the over-refining and over consumption of basic food groups (cereals and tubers) which provide limited amounts of

Shane R. McIntosh; Robert J. Henry



Translational upregulation of folate receptors is mediated by homocysteine via RNA-heterogeneous nuclear ribonucleoprotein E1 interactions  

PubMed Central

Cellular acquisition of folate is mediated by folate receptors (FRs) in many malignant and normal human cells. Although FRs are upregulated in folate deficiency and downregulated following folate repletion, the mechanistic basis for this relationship is unclear. Previously we demonstrated that interaction of an 18-base cis-element in the 5?-untranslated region of FR mRNA and a cystolic trans-factor (heterogeneous nuclear ribonucleoprotein E1 [hnRNP E1]) is critical for FR synthesis. However, the molecular mechanisms controlling this interaction, especially within the context of FR regulation and folate status, have remained obscure. Human cervical carcinoma cells exhibited progressively increasing upregulation of FRs after shifting of folate-replete cells to low-folate media, without a proportionate rise in FR mRNA or rise in hnRNP E1. Translational FR upregulation was accompanied by a progressive accumulation of the metabolite homocysteine within cultured cells, which stimulated interaction of the FR mRNA cis-element and hnRNP E1 as well as FR biosynthesis in a dose-dependent manner. Abrupt reversal of folate deficiency also led to a rapid parallel reduction in homocysteine and FR biosynthesis to levels observed in folate-replete cells. Collectively, these results suggest that homocysteine is the key modulator of translational upregulation of FRs and establishes the linkage between perturbed folate metabolism and coordinated upregulation of FRs. PMID:14722620

Antony, Asok C.; Tang, Ying-Sheng; Khan, Rehana A.; Biju, Mangatt P.; Xiao, Xiangli; Li, Qing-Jun; Sun, Xin-Lai; Jayaram, Hiremagalur N.; Stabler, Sally P.



Cerebral folate deficiency.  


Cerebral folate deficiency (CFD) can be defined as any neurological syndrome associated with low cerebrospinal fluid (CSF) 5-methyltetrahydrofolate (5MTHF), the active folate metabolite, in the presence of normal folate metabolism outside the nervous system. CFD could result from either disturbed folate transport or from increased folate turnover within the central nervous system (CNS). We report on a novel neurometabolic syndrome in 20 children, which we term 'idiopathic CFD'. Typical features became manifest from the age of 4 months, starting with marked unrest, irritability, and sleep disturbances followed by psychomotor retardation, cerebellar ataxia, spastic paraplegia, and dyskinesia; epilepsy developed in about one third of the children. Most children showed deceleration ofhead growth from the age of 4 to 6 months. Visual disturbances began to develop around the age of 3 years and progressive sensorineural hearing loss started from the age of 6 years. Neuroimaging showed atrophy of frontotemporal regions and periventricular demyelination in seven children, slowly progressive supra- and infratentorial atrophy in three children, and normal findings in the remainder. Because active folate transport to the CNS occurs through receptor-mediated folate receptor protein 1 (FR1) endocytosis, DNA sequencing of the FR1 gene was performed and found to be normal. However, CSF protein analysis revealed a non-functional FR1 protein, suspected to result from either post-translational defects of FR1 protein N-glycosylation, the presence of folate antagonists with irreversible binding, or autoantibodies blocking the folate binding site of FR1. Oral treatment with 5-formyltetrahydrofolate (folinic acid) should be started in low doses at 0.5-1mg/kg/day, but in some patients higher daily doses of folinic acid at 2-3 mg/kg/day are required to normalize CSF 5MTHF values. This proposed treatment protocol resulted in a favourable clinical response in patients identified before the age of six years while partial recovery with poorer outcome was found beyond the age of 6 years. Careful clinical and EEG monitoring should be performed 1, 3, and 6 months after the beginning of treatment. After four to six months of folinic acid treatment, CSF analysis should be repeated in order to prevent over- or under-dosage of folinic acid. Secondary forms of CFD have been recognized during chronic use of antifolate and anticonvulsant drugs and in various known conditions such as Rett syndrome, Aicardi-Goutières syndrome, 3-phosphoglycerate dehydrogenase deficiency, dihydropteridine reductase deficiency, aromatic amino acid decarboxylase deficiency, and Kearns-Sayre syndrome. The pathogenic link between these underlying specific disease entities and the observed secondary CFD has not been resolved. PMID:15581159

Ramaekers, Vincent Th; Blau, Nenad



Folate metabolism in renal failure.  


In most patients with chronic kidney disease, provision of sufficient human recombinant erythropoietin (rHuEPO) and iron replacement therapy will effectively correct renal anaemia. Folate deficiency has been implicated as a contributory factor in renal anaemia and hyporesponsiveness to rHuEPO treatment. As such, the necessity of regular folate supplementation has been debated over the last decade. Although folate loss through dialysis is greater than by urinary excretion, these losses are easily balanced by a normal mixed diet containing 60 g protein/day. Thus, unless patients show significant folate depletion, additional supplementation of folic acid does not appear to have a beneficial effect on erythropoiesis or on responsiveness to rHuEPO therapy. However, a diagnosis of folate deficiency should be considered in patients with chronic renal insufficiency and significant elevation in mean cell volume or hypersegmented polymorphonuclear leucocytes; in patients with malnutrition or a history of alcohol abuse, or in patients hyporesponsive to rHuEPO treatment, especially when accompanied by macrocytosis. Measurements of serum folate are not necessarily indicative of tissue folate stores and red blood cell (RBC) folate measures provide a more accurate picture. Low RBC folate concentrations in these patients indicate the need for folate supplementation. Folate supplementation can also reduce elevated levels of homocysteine in dialysis patients, which may contribute to the high cardiovascular morbidity prevalent in these individuals. High-dose folate therapy (5-15 mg/day) has been shown to reduce plasma homocysteine levels by 25-30% and appears to be well tolerated provided the patient has adequate vitamin B(12) stores. Although long-term benefits of this intervention for cardiovascular protection and patient survival have yet to be established, folic acid is considered a relatively non-toxic and well-tolerated vitamin. PMID:12091603

Teschner, Markus; Kosch, Markus; Schaefer, Roland M



Folate Deficiency Triggers an Oxidative-Nitrosative Stress-Mediated Apoptotic Cell Death and Impedes Insulin Biosynthesis in RINm5F Pancreatic Islet ?-Cells: Relevant to the Pathogenesis of Diabetes  

PubMed Central

It has been postulated that folic acid (folate) deficiency (FD) may be a risk factor for the pathogenesis of a variety of oxidative stress-triggered chronic degenerative diseases including diabetes, however, the direct evidence to lend support to this hypothesis is scanty. For this reason, we set out to study if FD can trigger the apoptotic events in an insulin-producing pancreatic RINm5F islet ? cells. When these cells were cultivated under FD condition, a time-dependent growth impediment was observed and the demise of these cells was demonstrated to be apoptotic in nature proceeding through a mitochondria-dependent pathway. In addition to evoke oxidative stress, FD condition could also trigger nitrosative stress through a NF-?B-dependent iNOS-mediated overproduction of nitric oxide (NO). The latter compound could then trigger depletion of endoplasmic reticulum (ER) calcium (Ca2+) store leading to cytosolic Ca2+ overload and caused ER stress as evidence by the activation of CHOP expression. Furthermore, FD-induced apoptosis of RINm5F cells was found to be correlated with a time-dependent depletion of intracellular gluthathione (GSH) and a severe down-regulation of Bcl-2 expression. Along the same vein, we also demonstrated that FD could severely impede RINm5F cells to synthesize insulin and their abilities to secret insulin in response to glucose stimulation were appreciably hampered. Even more importantly, we found that folate replenishment could not restore the ability of RINm5F cells to resynthesize insulin. Taken together, our data provide strong evidence to support the hypothesis that FD is a legitimate risk factor for the pathogenesis of diabetes. PMID:24223745

Wang, Yu-Huei; Chen, Chia-Hui; Mau, Shin-Yi; Ho, Chun-Te; Chang, Pey-Jium; Liu, Tsan-Zon; Chen, Ching-Hsein



Folate in Skin Cancer Prevention  

PubMed Central

Skin, the largest, most exposed organ of the body, provides a protective interface between humans and the environment. One of its primary roles is protection against exposure to sunlight, a major source of skin damage where the UV radiation (UVR) component functions as a complete carcinogen. Melanin pigmentation and the evolution of dark skin is an adaptive protective mechanism against high levels of UVR exposure. Recently, the hypothesis that skin pigmentation balances folate preservation and Vitamin D production has emerged. Both micronutrients are essential for reproductive success. Photodegradation of bioactive folates suggests a mechanism for the increased tendency of populations of low melanin pigmentation residing in areas of high UV exposure to develop skin cancers. Folate is proposed as a cancer prevention target for its role in providing precursors for DNA repair and replication, as well as its ability to promote genomic integrity through the generation of methyl groups needed for control of gene expression. The cancer prevention potential of folate has been demonstrated by large-scale epidemiological and nutritional studies indicating that decreased folate status increases the risk of developing certain cancers. While folate deficiency has been extensively documented by analysis of human plasma, folate status within skin has not been widely investigated. Nevertheless, inefficient delivery of micronutrients to skin and photolysis of folate argue that documented folate deficiencies will be present if not exacerbated in skin. Our studies indicate a critical role for folate in skin and the potential to protect sun exposed skin by effective topical delivery as a strategy for cancer prevention. PMID:22116700

Williams, J.D.; Jacobson, Elaine L.; Kim, H.; Kim, M.; Jacobson, M.K.



Folates in lettuce: a pilot study  

PubMed Central

Background Leafy vegetables are good sources of folates and food shops nowadays offer an increasing number of lettuce varieties. Objective To obtain data on the folate content and forms in common lettuce varieties and spinach sold in the Nordic countries, and to investigate effects of different storage conditions and preparations in the consumer's home or at lunchtime restaurants. Design Folate was analysed in eight different lettuce varieties and spinach using a validated high-performance liquid chromatographic method and the detected forms of folates were confirmed by a mass spectrometric detector [liquid chromatography–mass spectrometry (LC-MS)] following heat extraction, deconjugation with rat serum and purification by solid-phase extraction. Results Folate content, expressed in folic acid equivalents, in the lettuce samples varied six-fold, from 30 to 198 µg 100 g?1 on a fresh weight basis. The folate content was decreased by 14% after storage at 4°C for 8 days and by 2–40% after storage at 22°C for 2–4 h, depending on whether samples were stored as whole leaves, or small torn or cut pieces. LC-MS confirmed the identity of the folate forms: H4folate, 5-CH3-H4folate, 5-HCO-H4folate and 10-HCO-H4folate. Conclusion The considerable variation in folate content between varieties of lettuce in this pilot study, with one variety reaching the level found in spinach, indicates the potential to increase folate intake considerably by choosing folate-rich varieties of lettuce and storing at low temperatures.

Johansson, Madelene; Jägerstad, Margaretha; Frølich, Wenche



Mathematical Modelling of Folate Metabolism  

PubMed Central

Folate metabolism is a complex biological process that is influenced by many variables including transporters, co-factors and enzymes. Mathematical models provide a useful tool to evaluate this complex system and to elucidate hypotheses that would be otherwise untenable to test in vitro or in vivo. Forty years of model development and refinement along with enhancements in technology have led to systematic improvement in our biological understanding from these models. However, increased complexity does not always lead to increased understanding, and a balanced approach to modelling the system is often advantageous. This approach should address questions about sensitivity of the model to variation and incorporate genomic data. The folate model is a useful platform for investigating the effects of antifolates on the folate pathway. The utility of the model is demonstrated through interrogation of drug resistance, drug-drug interactions, drug selectivity, and drug doses and schedules. Mathematics can be used to create models with the ability to design and improve rationale therapeutic interventions. PMID:23703958

Panetta, John C.; Paugh, Steven W.



Opposing roles of folate in prostate cancer.  


The US diet has been fortified with folic acid to prevent neural tube defects since 1998. The Physician Data Queries from the National Cancer Institute describe folate as protective against prostate cancer, whereas its synthetic analog, folic acid, is considered to increase prostate cancer risk when taken at levels easily achievable by eating fortified food or taking over-the-counter supplements. We review the present literature to examine the effects of folate and folic acid on prostate cancer, help interpret previous epidemiologic data, and provide clarification regarding the apparently opposing roles of folate for patients with prostate cancer. A literature search was conducted in Medline to identify studies investigating the effect of nutrition and specifically folate and folic acid on prostate carcinogenesis and progression. In addition, the National Health and Nutrition Examination Survey database was analyzed for trends in serum folate levels before and after mandatory fortification. Folate likely plays a dual role in prostate carcinogenesis. There remains conflicting epidemiologic evidence regarding folate and prostate cancer risk; however, there is growing experimental evidence that higher circulating folate levels can contribute to prostate cancer progression. Further research is needed to clarify these complex relationships. PMID:23992971

Rycyna, Kevin J; Bacich, Dean J; O'Keefe, Denise S



Folates and Folic Acid: From Fundamental Research Toward Sustainable Health  

Microsoft Academic Search

Folates are of paramount importance in one-carbon metabolism of most organisms. Plants and microorganisms are able to synthesize folates de novo, making them the main dietary source for humans and animals, which are dependent on food or feed supplies for folates. Folate deficiency is an increasing problem in the developing, as well as in the developed regions of the world,

Dieter Blancquaert; Sergei Storozhenko; Karen Loizeau; Hans De Steur; Veerle De Brouwer; Jacques Viaene; Stéphane Ravanel; Fabrice Rébeillé; Willy Lambert; Dominique Van Der Straeten



Neural tube defects induced by folate deficiency in mutant curly tail (Grhl3) embryos are associated with alteration in folate one-carbon metabolism but are unlikely to result from diminished methylation  

PubMed Central

Background Folate one-carbon metabolism has been implicated as a determinant of susceptibility to neural tube defects (NTDs), owing to the preventive effect of maternal folic acid supplementation and the higher risk associated with markers of diminished folate status. Methods Folate one-carbon metabolism was compared in curly tail (ct/ct) and genetically matched congenic (+ct/+ct) mouse strains using the deoxyuridine suppression test in embryonic fibroblast cells and by quantifying s-adenosylmethionine (SAM) and s-adenosylhomocysteine (SAH) in embryos using liquid chromatography tandem mass spectrometry. A possible genetic interaction between curly tail and a null allele of 5,10-methylenetetrahydrofolate reductase (MTHFR) was investigated by generation of compound mutant embryos. Results There was no deficit in thymidylate biosynthesis in ct/ct cells but incorporation of exogenous thymidine was lower than in +ct/+ct cells. In +ct/+ct embryos the SAM/SAH ratio was diminished by dietary folate deficiency and normalised by folic acid or myor-inositol treatment, in association with prevention of NTDs. In contrast, folate deficiency caused a significant increase in SAM/SAH ratio in ct/ct embryos. Loss of MTHFR function in curly tail embryos significantly reduced the SAM/SAH ratio but did not cause cranial NTDs or alter the frequency of caudal NTDs. Conclusions Curly tail fibroblasts and embryos, in which Grhl3 expression is reduced, display alterations in one-carbon metabolism, particularly in the response to folate deficiency, compared with genetically-matched congenic controls in which Grhl3 is unaffected. However, unlike folate deficiency, diminished methylation potential appears to be insufficient to cause cranial NTDs in the curly tail strain, and neither does it increase the frequency of caudal NTDs. PMID:20589880

De Castro, Sandra CP; Leung, Kit-yi; Savery, Dawn; Burren, Katie; Rozen, Rima; Copp, Andrew J.; Greene, Nicholas D.E.



Folate Metabolism and Human Reproduction  

PubMed Central

Folate metabolism affects ovarian function, implantation, embryogenesis and the entire process of pregnancy. In addition to its well-established effect on the incidence of neural tube defects, associations have been found between reduced folic acid levels and increased homocysteine concentrations on the one hand, and recurrent spontaneous abortions and other complications of pregnancy on the other. In infertility patients undergoing IVF/ICSI treatment, a clear correlation was found between plasma folate concentrations and the incidence of dichorionic twin pregnancies. In patients supplemented with 0.4?mg/d folic acid undergoing ovarian hyperstimulation and oocyte pick-up, carriers of the MTHFR 677T mutation were found to have lower serum estradiol concentrations at ovulation and fewer oocytes could be retrieved from them. It appears that these negative effects can be compensated for in full by increasing the daily dose of folic acid to at least 0.8?mg. In carriers of the MTHFR 677TT genotype who receive appropriate supplementation, AMH concentrations were found to be significantly increased, which could indicate a compensatory mechanism. AMH concentrations in homozygous carriers of the MTHFR 677TT genotype could even be overestimated, as almost 20?% fewer oocytes are retrieved from these patients per AMH unit compared to MTHFR 677CC wild-type individuals. PMID:25278626

Thaler, C. J.



[Dairy products as source of folates].  


Dairy products, especially yoghurts and blue cheeses, are underestimated source of folates in human diet. Though foliates content in dairy products is lower than in vegetables and cereals, nevertheless their bioavailability and stability is much better. High folate stability results from presence of hydro- and lipophylic antioxidants efficiently protecting folates and other bioactive compounds against oxidation processes on synergic way. On the other hand, high bioavailability is a consequence of folic appearing in milk mainly in form of mono glutamates and also of a presence of a protein ready to bind folates (FBP--folic binding protein). FBP makes easier folates transport through cell membranes. Moreover, present in milk sphingolipids and cholesterol stimulate activity of FBP. Mould cheeses and milk fermented beverages contain the highest amount of folates. However, cottage cheese contain considerable amount of folic binding protein. Regular consumption of milk fermented beverages and eating them together with vegetables and fruits rich in folates is a chance to increase covering of folic demand. PMID:24868906

Kowalska, Marika; Cichosz, Grazyna



Folate and Alzheimer: when time matters.  


Folate is necessary for DNA and mtDNA integrity and via folate/B12-dependent methionine cycle for methylation of multiple substrates (epigenetic DNA and enzymes) and methylation of homocysteine. During embryogenesis, folate deficiency is a risk factor for neural tube defects and late in life for cognitive decline and Alzheimer's dementia (AD). It induces several Alzheimer pathomechanisms like oxidative stress, Ca(++) influx, accumulation of hyperphosphorylated tau and ?-amyloid. But impact of folic acid supplementation on prevention or delay of dementia is a matter of debate. Six out of seven randomized controlled trials (RCT) with B vitamin intervention periods between 2 and 5.4 years reported about cognitive benefits in the supplemented groups mainly for those subjects with high homocysteine or low folate levels at baseline. This review tries to demonstrate the connection between folate deficiency and AD, analyses selected epidemiologic studies and RCT on folate/B12/homocysteine with long-observation periods (? 2 years RCT; ? 4 years observational) and attempts to find explanations for the controversy in literature like short follow-up, heterogeneity of subjects concerning age, recruitment, baseline cognition, inclusion criteria and probably "misleading"(not representative for the past) folate/B12/homocysteine levels due to not reported short-term use of multivitamins or food-fortification. Population-based studies-epidemiologic and interventional-starting in the fourth decade would provide the best information about the impact of folate on later development of AD. Mandatory folate fortification areas will be important future field studies for-like neural tube defects-hopefully declining AD incidence and disproving safety concerns. PMID:22627695

Hinterberger, Margareta; Fischer, Peter



Zinc deficiency and dietary folate metabolism in pregnant rats.  


Five groups of pregnant Wistar rats (zinc-deficient diet without folate supplementation; folinic acid, folate monoglutamate, folate polyglutamate-supplemented groups receiving zinc-deficient diet; pair-fed groups as controls) were fed from day one of fertilization with a semisynthetic zinc-deficient diet containing 0.2 mg/kg of Zn in the diet for the 4 deficient groups and 100 mg/kg for the pair-fed group. After 20 days, the zinc status (plasma, liver, femoral bone) was significantly decreased in the zinc-deficient groups. The liver and plasma folate levels were lower in the zinc-deficient groups compared to the pair-fed group. Moreover, the folinic acid and the polyglutamate folate supplementations (100 mg/kg diet) did not normalize the folate status of the animals. Only the supplementation with folate monoglutamate led to correct folate levels in the pregnant rats. Nevertheless, no form of folate supplementation prevented fetal growth retardation in any of the zinc-deficient groups. These results indicate that zinc deficiency in pregnant rats decreases folate bioavailability of folinic acid, folate polyglutamates and, to a lesser extent, that of folate monoglutamate. However, no form of folate supplementation (i.e., folate monoglutamate) prevents fetal growth defect and the incidence of malformation in zinc-deficient rats. PMID:8400843

Favier, M; Faure, P; Roussel, A M; Coudray, C; Blache, D; Favier, A



Thiamine metabolism in folate deficient rats  

SciTech Connect

Folate status (FS) and resultant alterations in thiamine status (TS) were evaluated in weanling rats fed either 17% amino acids (RHAA); 14% amino acids (LOGLU); 20% Vitamin Free casein (VFC) + 8% gelatin (HICG); 10% VFC + 4% gelatin + 0.3% methionine (CGM); or 10% VFC + 4 % gelatin (LOCG). Diets were fed with and without 8 mg FA/kg diet. HICG diet contained 54 ug/kg endogenous folate, the CGM and LOCG, 27 ug/kg, RHAA and LOGLU were folate free. FS was assessed by growth rate, hematology, formiminoglutamic acid excretion following a histidine load and tissue folate levels. TS was assessed by determining the fate of oral /sup 3/H-labeled and intravenous /sup 14/C-labeled thiamine over a six hour test period and by measurement of blood transketolase activity (TKA) and TPP effect (TPPE). TKA and TPPE were measured by an enzymatic single-point assay developed during these investigations.

Walzem, R.L.



Genetics Home Reference: Cerebral folate transport deficiency  


... and Families Resources for Health Professionals What glossary definitions help with understanding cerebral folate transport deficiency? ataxia ; ... recessive ; regression ; tissue ; white matter You may find definitions for these and many other terms in the ...


Genetics Home Reference: Hereditary folate malabsorption  


... the production of DNA and its chemical cousin, RNA. Infants with hereditary folate malabsorption are born with ... anemia ; microvilli ; neurological ; platelets ; prevalence ; protein ; proton ; recessive ; RNA ; susceptibility ; thrombocytopenia ; vitamins ; white blood cells You may ...


Auxin biosynthesis.  


lndole-3-acetic acid (IAA), the most important natural auxin in plants, is mainly synthesized from the amino acid tryptophan (Trp). Recent genetic and biochemical studies in Arabidopsis have unambiguously established the first complete Trp-dependent auxin biosynthesis pathway. The first chemical step of auxin biosynthesis is the removal of the amino group from Trp by the TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS (TAA) family of transaminases to generate indole-3-pyruvate (IPA). IPA then undergoes oxidative decarboxylation catalyzed by the YUCCA (YUC) family of flavin monooxygenases to produce IAA. This two-step auxin biosynthesis pathway is highly conserved throughout the plant kingdom and is essential for almost all of the major developmental processes. The successful elucidation of a complete auxin biosynthesis pathway provides the necessary tools for effectively modulating auxin concentrations in plants with temporal and spatial precision. The progress in auxin biosynthesis also lays a foundation for understanding polar auxin transport and for dissecting auxin signaling mechanisms during plant development. PMID:24955076

Zhao, Yunde



Auxin Biosynthesis  

PubMed Central

lndole-3-acetic acid (IAA), the most important natural auxin in plants, is mainly synthesized from the amino acid tryptophan (Trp). Recent genetic and biochemical studies in Arabidopsis have unambiguously established the first complete Trp-dependent auxin biosynthesis pathway. The first chemical step of auxin biosynthesis is the removal of the amino group from Trp by the TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS (TAA) family of transaminases to generate indole-3-pyruvate (IPA). IPA then undergoes oxidative decarboxylation catalyzed by the YUCCA (YUC) family of flavin monooxygenases to produce IAA. This two-step auxin biosynthesis pathway is highly conserved throughout the plant kingdom and is essential for almost all of the major developmental processes. The successful elucidation of a complete auxin biosynthesis pathway provides the necessary tools for effectively modulating auxin concentrations in plants with temporal and spatial precision. The progress in auxin biosynthesis also lays a foundation for understanding polar auxin transport and for dissecting auxin signaling mechanisms during plant development. PMID:24955076

Zhao, Yunde





... or moderate cognitive impairment received one of three treatments for 24 weeks: 400 mcg folic acid plus 1 ... a potential role as a supplement to other treatment for depression," although whether this applies to both people ...


Subacute combined degeneration of the cord due to folate deficiency: response to methyl folate treatment  

Microsoft Academic Search

Subacute combined degeneration of the cord is a rare complication of folate deficiency. Disturbance of methylation reactions in nervous tissue probably underlie subacute combined degeneration of the cord arising from folate as well as vitamin B12 deficiency. Methyl tetrahydrofolate is the form in which folic acid is transported into the CNS. Therefore methyl tetrahydrofolate treatment of the neurological and psychiatric

E G Lever; R D Elwes; A Williams; E H Reynolds



Quantitative flux analysis reveals folate-dependent NADPH production.  


ATP is the dominant energy source in animals for mechanical and electrical work (for example, muscle contraction or neuronal firing). For chemical work, there is an equally important role for NADPH, which powers redox defence and reductive biosynthesis. The most direct route to produce NADPH from glucose is the oxidative pentose phosphate pathway, with malic enzyme sometimes also important. Although the relative contribution of glycolysis and oxidative phosphorylation to ATP production has been extensively analysed, similar analysis of NADPH metabolism has been lacking. Here we demonstrate the ability to directly track, by liquid chromatography-mass spectrometry, the passage of deuterium from labelled substrates into NADPH, and combine this approach with carbon labelling and mathematical modelling to measure NADPH fluxes. In proliferating cells, the largest contributor to cytosolic NADPH is the oxidative pentose phosphate pathway. Surprisingly, a nearly comparable contribution comes from serine-driven one-carbon metabolism, in which oxidation of methylene tetrahydrofolate to 10-formyl-tetrahydrofolate is coupled to reduction of NADP(+) to NADPH. Moreover, tracing of mitochondrial one-carbon metabolism revealed complete oxidation of 10-formyl-tetrahydrofolate to make NADPH. As folate metabolism has not previously been considered an NADPH producer, confirmation of its functional significance was undertaken through knockdown of methylenetetrahydrofolate dehydrogenase (MTHFD) genes. Depletion of either the cytosolic or mitochondrial MTHFD isozyme resulted in decreased cellular NADPH/NADP(+) and reduced/oxidized glutathione ratios (GSH/GSSG) and increased cell sensitivity to oxidative stress. Thus, although the importance of folate metabolism for proliferating cells has been long recognized and attributed to its function of producing one-carbon units for nucleic acid synthesis, another crucial function of this pathway is generating reducing power. PMID:24805240

Fan, Jing; Ye, Jiangbin; Kamphorst, Jurre J; Shlomi, Tomer; Thompson, Craig B; Rabinowitz, Joshua D



Folate Status and Risk of Colorectal Polyps in African Americans  

Microsoft Academic Search

Dietary folate status appears to influence risk for colorectal cancer possibly by alterations in DNA methylation and nucleotide\\u000a precursor pools. Polymorphisms (677C?T and 1298A?C) in methylenetetrahydrofolate reductase (MTHFR), a key enzyme in folate\\u000a metabolism, determines enzyme activity. The frequency of polymorphisms in the gene varies extensively in different populations.\\u000a We sought to determine the association between folate status, folate metabolism,

H. Ashktorab; R. Begum; A. Akhgar; D. T. Smoot; M. Elbedawi; M. Daremipouran; A. Zhao; B. Momen; F. M. Giardiello



Isotope Ratio-Based Profiling of Microbial Folates  

E-print Network

, Princeton, New Jersey, USA Folate metabolism, which is responsible for one-carbon transfer reactionsIsotope Ratio-Based Profiling of Microbial Folates Wenyun Lu, Yun Kyung Kwon, and Joshua D folate standards. An isotope-ratio-based approach has been applied to study the effects of trimethoprim

Rabinowitz, Joshua D.


Folates in fermented vegetables—a pilot study  

Microsoft Academic Search

The present work aimed to evaluate whether lactic acid fermentation can increase folate concentrations in vegetables making these foods superior to similar foods produced by the more common preservation techniques. The concentrations of folates present in raw vegetables, usually root vegetables, were followed during pre-treatment and fermentation with the purpose to improve the folate retention. Commercial starter cultures aimed for

M Jägerstad; J Jastrebova; U Svensson



Folate supplementation and methotrexate treatment in rheumatoid arthritis: a review  

Microsoft Academic Search

Objectives. The folate antagonist methotrexate (MTX) has become established as the most commonly used disease-modifying anti-rheumatic drug (DMARD) in the treatment of rheumatoid arthritis (RA) but is commonly discontinued due to adverse effects. Adverse effects are thought to be mediated via folate antagonism. In this paper we summarize the current data on the use of folates as a supplement to

S. L. Whittle; R. A. Hughes



Production of folates by yeasts in Tanzanian fermented togwa.  


We have investigated the impact of different yeasts and fermentation time on folate content and composition in a fermented maize-based porridge, called togwa, consumed in rural areas in Tanzania. The yeasts studied, originally isolated from indigenous togwa, belong to Issatchenkia orientalis, Pichia anomala, Saccharomyces cerevisiae, Klyveromyces marxianus and Candida glabrata. The main folate forms found, detected and quantified by HPLC during the fermentations were 5-methyl-tetrahydrofolate (5-CH(3)-H(4)folate) and tetrahydrofolate (H(4)folate). The content of H(4)folate, per unit togwa, remained fairly stable at a low level throughout the experiment for all strains, whereas the 5-CH(3)-H(4)folate concentration was highly dependent on yeast strain as well as on fermentation time. The highest folate concentration was found after 46 h of fermentation with C. glabrata (TY26) (6.91+/-0.14 microg 100 mL(-1)), corresponding to a 23-fold increase compared with unfermented togwa. The cell concentration per se could not predict the togwa folate level, as shown by the much higher specific folate content (g folate CFU(-1)) in the S. cerevisiae strain (TY08) compared with the other species tested. This study provides useful data when trying to maximize folate content in togwa as well as in other yeast-fermented products. PMID:18547328

Hjortmo, Sofia B; Hellström, Andreas M; Andlid, Thomas A



Impact of folate therapy on combined immunodeficiency secondary to hereditary folate malabsorption.  


Hereditary folate malabsorption (HFM) is a rare autosomal recessive disorder. Severe folate deficiency in HFM can result in immunodeficiency. We describe a female infant with HFM who acquired severe Pneumocystis pneumonia. The objective of the present study was to elucidate her immunological phenotype and to examine the time course of immune recovery following parenteral folate therapy. The patient demonstrated a combined immunodeficiency with an impaired T cell proliferation response, pan-hypogammaglobulinemia, and an imbalanced pro-inflammatory cytokine profile. She had normal white blood cell count, normal lymphocyte subsets, and normal complement levels. Two novel mutations were identified within the SLC46A1 gene to produce a compound heterozygote. We confirmed full recovery of her immunological and neurophysiological status with parenteral folate replacement. The time course of recovery of her immunological profile varied widely, however. HFM should be recognized as a unique form of immunodeficiency. PMID:24691418

Kishimoto, Kenji; Kobayashi, Ryoji; Sano, Hirozumi; Suzuki, Daisuke; Maruoka, Hayato; Yasuda, Kazue; Chida, Natsuko; Yamada, Masafumi; Kobayashi, Kunihiko



Mechanisms of folate losses during processing: diffusion vs. heat degradation.  


Though folates are sensitive to heat treatments, leaching appears to be a major mechanism involved in folate losses in vegetables during processing. The aim of our study was to study folate diffusivity and degradation from spinach and green beans, in order to determine the proportion of each mechanism involved in folate losses. Folate diffusivity constant, calculated according to Fick's second law (Crank, 1975), was 7.4×10(-12) m(2)/s for spinach and 5.8×10(-10) m(2)/s for green beans, which is the same order of magnitude as for sugars and acids for each vegetable considered. Folate thermal degradation kinetics was not monotonous in spinach and green beans especially at 45 °C and did not follow a first order reaction. The proportion of vitamers changed markedly after thermal treatment, with a better retention of formyl derivatives. For spinach, folate losses were mainly due to diffusion while for green beans thermal degradation seemed to be preponderant. PMID:24679802

Delchier, Nicolas; Ringling, Christiane; Maingonnat, Jean-François; Rychlik, Michael; Renard, Catherine M G C



Structures of human folate receptors reveal biological trafficking states and diversity in folate and antifolate recognition  

PubMed Central

Antifolates, folate analogs that inhibit vitamin B9 (folic acid)-using cellular enzymes, have been used over several decades for the treatment of cancer and inflammatory diseases. Cellular uptake of the antifolates in clinical use occurs primarily via widely expressed facilitative membrane transporters. More recently, human folate receptors (FRs), high affinity receptors that transport folate via endocytosis, have been proposed as targets for the specific delivery of new classes of antifolates or folate conjugates to tumors or sites of inflammation. The development of specific, FR-targeted antifolates would be accelerated if additional biophysical data, particularly structural models of the receptors, were available. Here we describe six distinct crystallographic models that provide insight into biological trafficking of FRs and distinct binding modes of folate and antifolates to these receptors. From comparison of the structures, we delineate discrete structural conformations representative of key stages in the endocytic trafficking of FRs and propose models for pH-dependent conformational changes. Additionally, we describe the molecular details of human FR in complex with three clinically prevalent antifolates, pemetrexed (also Alimta), aminopterin, and methotrexate. On the whole, our data form the basis for rapid design and implementation of unique, FR-targeted, folate-based drugs for the treatment of cancer and inflammatory diseases. PMID:23934049

Wibowo, Ardian S.; Singh, Mirage; Reeder, Kristen M.; Carter, Joshua J.; Kovach, Alexander R.; Meng, Wuyi; Ratnam, Manohar; Zhang, Faming; Dann, Charles E.



Iron and Folate-Deficiency Anaemias.  

ERIC Educational Resources Information Center

Nutritional anemia is believed to be the most widespread nutritional disorder in the world. While it generally affects developing countries, developed countries are also affected to an extent sufficient to justify the implementation of preventive measures at a national level. This report focuses on iron and folate deficiencies, which are by far…

Hercberg, Serge



UK Policy on Folate Fortification of Foods  

ERIC Educational Resources Information Center

The UK Food Standards Agency has decided not to recommend fortification of foods with folate, the family of vitamins associated with the prevention of neural tube defects in babies. This is a change in attitude from previous recommendations made by a series of committees and reports in the UK. Notably, it differs from US policy on the matter. The…

Malcolm, Alan



Beyaz®: an oral contraceptive fortified with folate.  


Beyaz(®) (Bayer HealthCare Pharmaceuticals, Berlin, Germany) consists of 28 film-coated tablets: 24 tablets each containing 3 mg drospirenone plus 20 µg ethinylestradiol (EE) and 451 µg levomefolate calcium followed by four tablets, each containing 451 µg levomefolate calcium. It has the same indications of the parent compound 20 µg EE/3 mg drospirenone in a 24/4-day regimen (i.e., contraception, moderate acne, premenstrual dysforic disorder). In addition, the 24-day regimen with 20 µg EE/3 mg drospirenone/levomefolate calcium assure significant increases in red blood cell and plasma folate levels reaching values indicated to be protective in reducing the risk of neural tube defects. A progressive decrease in folate levels has been observed in women taking a 30 µg EE pill fortified with the same dose of levomefolate calcium upon discontinuation. At 4 and 8 weeks following cessation of the oral contraceptive, red blood cell folate levels >906 nmol/l were measured in 85 and 60% of women respectively. Because of this, the folate-containing pill may aid in reducing the risk of neural tube defects in a pregnancy conceived during use or shortly after the discontinuation of the product. PMID:22171769

Fruzzetti, Franca



Folate Augmentation of Treatment – Evaluation for Depression (FolATED): protocol of a randomised controlled trial  

PubMed Central

Background Clinical depression is common, debilitating and treatable; one in four people experience it during their lives. The majority of sufferers are treated in primary care and only half respond well to active treatment. Evidence suggests that folate may be a useful adjunct to antidepressant treatment: 1) patients with depression often have a functional folate deficiency; 2) the severity of such deficiency, indicated by elevated homocysteine, correlates with depression severity, 3) low folate is associated with poor antidepressant response, and 4) folate is required for the synthesis of neurotransmitters implicated in the pathogenesis and treatment of depression. Methods/Design The primary objective of this trial is to estimate the effect of folate augmentation in new or continuing treatment of depressive disorder in primary and secondary care. Secondary objectives are to evaluate the cost-effectiveness of folate augmentation of antidepressant treatment, investigate how the response to antidepressant treatment depends on genetic polymorphisms relevant to folate metabolism and antidepressant response, and explore whether baseline folate status can predict response to antidepressant treatment. Seven hundred and thirty patients will be recruited from North East Wales, North West Wales and Swansea. Patients with moderate to severe depression will be referred to the trial by their GP or Psychiatrist. If patients consent they will be assessed for eligibility and baseline measures will be undertaken. Blood samples will be taken to exclude patients with folate and B12 deficiency. Some of the blood taken will be used to measure homocysteine levels and for genetic analysis (with additional consent). Eligible participants will be randomised to receive 5 mg of folic acid or placebo. Patients with B12 deficiency or folate deficiency will be given appropriate treatment and will be monitored in the 'comprehensive cohort study'. Assessments will be at screening, randomisation and 3 subsequent follow-ups. Discussion If folic acid is shown to improve the efficacy of antidepressants, then it will provide a safe, simple and cheap way of improving the treatment of depression in primary and secondary care. Trial registration Current controlled trials ISRCTN37558856 PMID:18005429

Roberts, Seren Haf; Bedson, Emma; Hughes, Dyfrig; Lloyd, Keith; Moat, Stuart; Pirmohamed, Munir; Slegg, Gary; Tranter, Richard; Whitaker, Rhiannon; Wilkinson, Clare; Russell, Ian



Folate and B12 in prostate cancer.  


Mechanisms postulated to link folate and B12 metabolism with cancer, including genome-wide hypomethylation, gene-specific promoter hypermethylation, and DNA uracil misincorporation, have been observed in prostate tumor cells. However, epidemiological studies of prostate cancer risk, based on dietary intakes and blood levels of folate and vitamin B12 and on folate-pathway gene variants, have generated contradictory findings. In a meta-analysis, circulating concentrations of B12 (seven studies, OR = 1.10; 95% CI 1.01, 1.19; P = 0.002) and (in cohort studies) folate (five studies, OR = 1.18; 95% CI 1.00, 1.40; P = 0.02) were positively associated with an increased risk of prostate cancer. Homocysteine was not associated with risk of prostate cancer (four studies, OR = 0.91; 95% CI 0.69, 1.19; P = 0.5). In a meta-analysis of folate-pathway polymorphisms, MTR 2756A > G (eight studies, OR = 1.06; 95% CI 1.00, 1.12; P = 0.06) and SHMT1 1420C > T (two studies, OR = 1.11; 95% CI 1.00, 1.22; P = 0.05) were positively associated with prostate cancer risk. There were no effects due to any other polymorphisms, including MTHFR 677C > T (12 studies, OR = 1.04; 95% CI 0.97, 1.12; P = 0.3). The positive association of circulating B12 with an increased risk of prostate cancer could be explained by reverse causality. However, given current controversies over mandatory B12 fortification, further research to eliminate a causal role of B12 in prostate cancer initiation and/or progression is required. Meta-analysis does not entirely rule out a positive association of circulating folate with increased prostate cancer risk. As with B12, even a weak positive association would be a significant public health issue, given the high prevalence of prostate cancer and concerns about the potential harms versus benefits of mandatory folic acid fortification. PMID:23724740

Collin, Simon M



Novel insights on interactions between folate and lipid metabolism.  


Folate is an essential B vitamin required for the maintenance of AdoMet-dependent methylation. The liver is responsible for many methylation reactions that are used for post-translational modification of proteins, methylation of DNA, and the synthesis of hormones, creatine, carnitine, and phosphatidylcholine. Conditions where methylation capacity is compromised, including folate deficiency, are associated with impaired phosphatidylcholine synthesis resulting in non-alcoholic fatty liver disease and steatohepatitis. In addition, folate intake and folate status have been associated with changes in the expression of genes involved in lipid metabolism, obesity, and metabolic syndrome. In this review, we provide insight on the relationship between folate and lipid metabolism, and an outlook for the future of lipid-related folate research. PMID:24353111

da Silva, Robin P; Kelly, Karen B; Al Rajabi, Ala; Jacobs, René L



Interactions between folates and carbamazepine or valproate in the rat.  


Carbamazepine and valproate each afforded protection against seizures induced by electroshock or by inhalation of hexafluorodiethyl ether (HFDE). After injections of either anticonvulsant for 10 days, plasma folate concentration decreased, but brain folate concentration did not change. Folinic acid administration had no effect on the concentration of either anticonvulsant in plasma or brain. These findings are in contrast with the demonstrated effects of other anticonvulsants on folate biochemistry. PMID:6810206

Smith, D B; Carl, G F



Reduced folate carrier polymorphisms and neural tube defect risk  

Microsoft Academic Search

The reduced folate carrier (RFCI) is essential for folate transport into cells. Low folate is an important cause of neural tube defects (NTDs), and a single-nucleotide polymorphism (H27R) (80G?A) in the RFCI gene has been reported to be a NTD risk factor. We investigated H27R and a 61bp tandem repeat polymorphism as potential risk factors for NTDs, using a large

Valerie B. O’Leary; Faith Pangilinan; Christopher Cox; Anne Parle-McDermott; Mary Conley; Anne M. Molloy; Peadar N. Kirke; James L. Mills; Lawrence C. Brody; John M. Scott



Examining the folate status of Canadians: An analysis of the Canadian Health Measures Survey to assess and guide folate policies.  


Canada fortifies certain products with folic acid and has periconceptional supplementation guidelines [Formula: see text] policies designed to improve folate status and reduce the incidence of poor birth outcomes. Though optimal folate concentrations have been linked to health benefits, concerns have been raised regarding potential associations with adverse health outcomes. Direct biochemical assessment of the folate status of Canadians based on a nationally representative sample has not been done in more than 40 years. The overall purpose of this research was to investigate the folate status of the Canadian population. All analyses used the nationally representative 2007-2009 Canadian Health Measures Survey (CHMS). Red blood cell (RBC) folate was measured by Immulite 2000 immunoassay. Key findings indicate that folate deficiency (<305 nmol/L) was virtually nonexistent in the Canadian population (6-79 years old). Still, one-fifth of women of childbearing age (WCBA; 15-45 years old) had suboptimal concentrations for the prevention of neural tube defects (<906 nmol/L). Folic acid supplement intake was a primary determinant of WCBA, achieving a RBC folate concentration of ?906 nmol/L. A distinct shift towards elevated RBC folate concentrations emerged. Three hypothetical cut-offs (1450 nmol/L, 1800 nmol/L and 2150 nmol/L) were examined to create a dialogue since a universal definition of high RBC folate concentration does not exist. Females, participants aged 60-79 years, and those who were overweight or obese had the greatest prevalence of having high RBC folate at each cut-off. We conducted the first national-level comparison of RBC folate concentrations between the United States and Canada. Two different folate assay methods [Formula: see text] microbiologic assay (NHANES) and Immulite 2000 immunoassay (CHMS) [Formula: see text] necessitated the application of a conversion equation. Median Canadian RBC folate concentrations (adjusted to microbiologic assay) were lower than those of Americans but unadjusted Canadian median RBC folate values were higher. Canadian WCBA were less likely than American WCBA to have RBC folate ?906 nmol/L, though Canadian WCBA with unadjusted RBC folate values were more likely to achieve this cut-off. These results indicate a need for strategies targeting WCBA to improve compliance with folic acid supplement recommendations. The strength and necessity of supplements for the general population should be re-assessed. Further, harmonization of folate measurement procedures in future surveillance efforts would support comparisons and inform policy directions. PMID:24552387

Colapinto, Cynthia K



Folate: A Key to Optimal Pregnancy Outcome  

Microsoft Academic Search

Folate is a water-soluble vitamin required for cell division and normal growth. Studies have definitively shown that when\\u000a the synthetic form of the vitamin, folic acid, is taken during the periconceptional period, there is a significant reduction\\u000a in risk for neural tube defects (NTDs) and findings have been translated into public health policy to increase intake through\\u000a supplementation and fortification.

Beth Thomas Falls; Lynn B. Bailey


Quantitation of Red Blood Cell Folates by Stable Isotope Dilution Gas Chromatography-Mass Spectrometry Utilizing a Folate Internal Standard  

Microsoft Academic Search

We report a new gas chromatography-mass spectrometry (GC-MS) method of measurement of red blood cell folates utilizing a stable isotope-labeled bacterial synthesized folate internal standard. The GC-MS method exploits the fact that the common feature of all folate molecules is a p-aminobenzoic acid moiety sandwiched between a pteridine ring and a polyglutamate chain of varying length. In this method, red

C. R. Santhoshkumar; J. C. Deutsch; K. L. Hassell; N. M. Kolhouse; J. F. Kolhouse



Utility of measuring serum or red blood cell folate in the era of folate fortification of flour.  


Folic acid is an essential nutrient involved in one-carbon metabolism. Insufficient folate can result in megaloblastic anemia and an increased risk of neural tube defects. In response to the latter, some governments have mandated the fortification of flour with folate. This had resulted in a documented rise in the serum and red blood cell folate levels in the population. This has impacted the potential utility of folate measurements to detect folate deficiency in the clinical context. Folate measurements, whether done in serum or red blood cells, are subject to analytical variation, especially the latter, which also affects the utility of such measurements. Examining the literature reveals that in clinical situations, generally <1% of the subjects will have folate deficiency regardless of potentially pre-disposing factors (e.g. anemia, anti-folate agents, inflammatory bowel disease). Data from our center for both pediatric and adult populations is presented that supports this observation. Consequently, there exists very few indications for folate determinations (unexplained macrocytosis, inborn errors of metabolism) and it may be more efficient to simply treat suspected cases. PMID:24486651

Gilfix, Brian M



Nuclear Localization of de Novo Thymidylate Biosynthesis Pathway Is Required to Prevent Uracil Accumulation in DNA*  

PubMed Central

Uracil accumulates in DNA as a result of impaired folate-dependent de novo thymidylate biosynthesis, a pathway composed of the enzymes serine hydroxymethyltransferase (SHMT), thymidylate synthase (TYMS), and dihydrofolate reductase. In G1, this pathway is present in the cytoplasm and at S phase undergoes small ubiquitin-like modifier-dependent translocation to the nucleus. It is not known whether this pathway functions in the cytoplasm, nucleus, or both in vivo. SHMT1 generates 5,10-methylenetetrahydrofolate for de novo thymidylate biosynthesis, a limiting step in the pathway, but also tightly binds 5-methyltetrahydrofolate in the cytoplasm, a required cofactor for homocysteine remethylation. Overexpression of SHMT1 in cell cultures inhibits folate-dependent homocysteine remethylation and enhances thymidylate biosynthesis. In this study, the impact of increased Shmt1 expression on folate-mediated one-carbon metabolism was determined in mice that overexpress the Shmt1 cDNA (Shmt1tg+ mice). Compared with wild type mice, Shmt1tg+ mice exhibited elevated SHMT1 and TYMS protein levels in tissues and evidence for impaired homocysteine remethylation but surprisingly exhibited depressed levels of nuclear SHMT1 and TYMS, lower rates of nuclear de novo thymidylate biosynthesis, and a nearly 10-fold increase in uracil content in hepatic nuclear DNA when fed a folate- and choline-deficient diet. These results demonstrate that SHMT1 and TYMS localization to the nucleus is essential to prevent uracil accumulation in nuclear DNA and indicate that SHMT1-mediated nuclear de novo thymidylate synthesis is critical for maintaining DNA integrity. PMID:22057276

MacFarlane, Amanda J.; Anderson, Donald D.; Flodby, Per; Perry, Cheryll A.; Allen, Robert H.; Stabler, Sally P.; Stover, Patrick J.



Human folate metabolism using 14C-accelerator mass spectrometry  

SciTech Connect

Folate is a water soluble vitamin required for optimal health, growth and development. It occurs naturally in various states of oxidation of the pteridine ring and with varying lengths to its glutamate chain. Folates function as one-carbon donors through methyl transferase catalyzed reactions. Low-folate diets, especially by those with suboptimal methyltransferase activity, are associated with increased risk of neural tube birth defects in children, hyperhomocysteinemic heart disease, and cancer in adults. Rapidly dividing (neoplastic) cells have a high folate need for DNA synthesis. Chemical analogs of folate (antifolates) that interfere with folate metabolism are used as therapeutic agents in cancer treatment. Although much is known about folate chemistry, metabolism of this vitamin in vivo in humans is not well understood. Since folate levels in blood and tissues are very low and methods to measure them are inadequate, the few previous studies that have examined folate metabolism used large doses of radiolabeled folic acid in patients with Hodgkin?s disease and cancer (Butterworth et al. 1969, Krumdieck et al. 1978). A subsequent protocol using deuterated folic acid was also insufficiently sensitive to trace a physiologic folate dose (Stites et al. 1997). Accelerator mass spectrometry (AMS) is an emerging bioanalytical tool that overcomes the limitations of traditional mass spectrometry and of decay counting of long lived radioisotopes (Vogel et al. 1995). AMS can detect attomolar concentrations of 14 C in milligram-sized samples enabling in vivo radiotracer studies in healthy humans. We used AMS to study the metabolism of a physiologic 80 nmol oral dose of 14 C-folic acid (1/6 US RDA) by measuring the 14 C-folate levels in serial plasma, urine and feces samples taken over a 150-day period after dosing a healthy adult volunteer.

Arjomand, A; Bucholz, B A; Clifford, A J; Duecker, S R; Johnson, H; Schneider, P D; Zulim, R A



Bioavailability of food folates and evaluation of food matrix effects with a rat bioassay.  


Folate bioavailability of beef liver, lima beans, peas, spinach, mushrooms, collards, orange juice and wheat germ was estimated with a protocol of folate depletion-repletion using growth and liver, serum and erythrocyte folate of weanling male rats. Diets with 125, 250 and 375 micrograms folic acid/kg were standards. Individual foods were incorporated into a folate-free amino acid-based diet alone (250 micrograms folate/kg diet from food) or mixed with folic acid (125 micrograms folate from food + 125 micrograms folic acid) to evaluate folate bioavailability and effects of food matrix. Beef liver and orange juice folates were as available as folic acid, whereas those of wheat germ were less bioavailable. Folates of peas and spinach were also less available than folic acid using liver and serum folate concentrations and total liver folate as response criteria, but they were not lower when based on growth and erythrocyte folate concentrations. Lima bean, mushroom and collard folates were as available as folic acid using four of five response criteria. Folate bioavailability of all foods generally exceeded 70%. All response criteria gave approximately equivalent results, indicating that growth and tissue folate levels are appropriate criteria. No food matrix effects were observed for any food except lima beans. Foods rich in polyglutamyl folates were less bioavailable than those of foods rich in short-chain folates. PMID:2007897

Clifford, A J; Heid, M K; Peerson, J M; Bills, N D



Interplay between Sucrose and Folate Modulates Auxin Signaling in Arabidopsis1[W][OA  

PubMed Central

As sessile organisms growing in an ever-changing environment, plants must integrate multiple regulatory inputs to promote the appropriate developmental responses. One such nutritional signal is cellular sugar levels, which rise and fall throughout the day and affect a variety of developmental processes. To uncover signaling pathways that modulate sugar perception, compounds from the Library of Active Compounds in Arabidopsis were screened for the ability to perturb developmental responses to sucrose (Suc) in Arabidopsis (Arabidopsis thaliana) seedlings. This screen found that sulfonamides, which inhibit folate biosynthesis in plants, restrict hypocotyl elongation in a sugar-dependent fashion. Transcriptome analysis identified a small set of transcripts that respond to the interaction between sulfonamide and Suc, including a number of transcripts encoding Auxin/Indole-3-Acetic Acids, negative regulators of auxin signal transduction. Chemical inhibition of auxin transport or genetic disruption of auxin signaling relieved this interaction, suggesting that responses to these two nutritional stimuli are mediated by auxin. Reporter systems used to track auxin signaling and distribution showed enhanced activity in the vascular region of the hypocotyl in response to cotreatment of Suc and sulfonamide, yet no change in auxin abundance was observed. Taken together, these findings suggest that the interplay between Suc and folates acts to fine-tune auxin sensitivity and influences auxin distribution during seedling development. PMID:23690535

Stokes, Michael E.; Chattopadhyay, Abhishek; Wilkins, Olivia; Nambara, Eiji; Campbell, Malcolm M.




EPA Science Inventory

Folate deficiency increases background levels of DNA damage and can enhance the mutagenicity of chemical agents. Duplicate experiments were performed to investigate the effect of dietary folate deficiency on arsenic induction of micronuclei (MN) in peripheral blood cells. Male C5...


Clinical utility of folate-containing oral contraceptives  

PubMed Central

Folate is a generic term for a water-soluble B-complex vitamin which plays an important role in protein synthesis and metabolism and other processes related to cell multiplication and tissue growth. Pregnant and lactating women are at increased risk of folic acid deficiency because generally their dietary folate is insufficient to meet their physiological requirements and the metabolic demands of the growing fetus. The evidence pertaining to the reduction of the risk of neural tube defects (NTDs) due to folate is so compelling that supplementation with 400 ?g of folic acid to all women trying to conceive until 12 weeks of pregnancy has been recommended by every relevant authority. A recent Cochrane review has also found protective effects of folate supplementation in occurrence and reoccurrence of NTDs. Despite food fortification and targeted public health campaigns promoting folic acid supplementation, 4,300,000 new cases occur each year worldwide resulting in an estimated 41,000 deaths and 2.3 million disability-adjusted life years (DALYS). This article will review the burden and risk factors of NTDS, and the role of folate in preventing NTDs. It will also describe different modes of supplementing folate and the newer evidence of the effectiveness of adding folate in oral contraceptives for raising serum and red blood cell folate levels. PMID:22570577

Lassi, Zohra S; Bhutta, Zulfiqar A



Body mass index and serum folate in childbearing age women  

Microsoft Academic Search

Background: Higher pre-pregnancy body mass index (BMI) is associated with increased risk of neural tube defects (NTDs) and possibly other negative birth outcomes in the offspring. The mechanism for this association remains unknown. Lower maternal folate level has been implicated in the etiology of NTDs in general. The association of BMI?with folate level, however, has not been investigated. Methods: The

Ramin Mojtabai



Strategies for potentiation of ethionamide and folate antagonists against Mycobacterium tuberculosis.  


Antifolates inhibit de novo folate biosynthesis, whereas ethionamide targets the mycolate synthetic pathway in Mycobacterium tuberculosis. These antibiotics are effective against M. tuberculosis but their use has been hampered by concerns over toxicity and low therapeutic indexes. With the increasing spread of drug-resistant forms, interest in using old drugs for tuberculosis treatment has been renewed. Specific inhibitors targeting resistance mechanisms could sensitize M. tuberculosis to these available, clinically approved drugs. This review discusses recently developed strategies to boost the antituberculous activity of ethionamide and antifolates. These approaches might help broaden the currently limited chemotherapeutic options of not only drug-resistant but also drug-susceptible tuberculosis, which still remains one of the most common infectious diseases in the developing world. PMID:23106273

Wolff, Kerstin A; Nguyen, Liem



Strategies for potentiation of ethionamide and folate antagonists against Mycobacterium tuberculosis  

PubMed Central

Antifolates inhibit de novo folate biosynthesis, whereas ethionamide targets the mycolate synthetic pathway in Mycobacterium tuberculosis. These antibiotics are effective against M. tuberculosis but their use has been hampered by concerns over toxicity and low therapeutic indexes. With the increasing spread of drug-resistant forms, interest in using old drugs for tuberculosis treatment has been renewed. Specific inhibitors targeting resistance mechanisms could sensitize M. tuberculosis to these available, clinically approved drugs. This review discusses recently developed strategies to boost the antituberculous activity of ethionamide and antifolates. These approaches might help broaden the currently limited chemotherapeutic options of not only drug-resistant but also drug-susceptible tuberculosis, which still remains one of the most common infectious diseases in the developing world. PMID:23106273

Wolff, Kerstin A; Nguyen, Liem



Disruption of the folate pathway in zebrafish causes developmental defects  

PubMed Central

Background Folic acid supplementation reduces the risk of neural tube defects and congenital heart defects. The biological mechanisms through which folate prevents birth defects are not well understood. We explore the use of zebrafish as a model system to investigate the role of folate metabolism during development. Results We first identified zebrafish orthologs of 12 human folate metabolic genes. RT-PCR and in situ analysis indicated maternal transcripts supply the embryo with mRNA so that the embryo has an intact folate pathway. To perturb folate metabolism we exposed zebrafish embryos to methotrexate (MTX), a potent inhibitor of dihydrofolate reductase (Dhfr) an essential enzyme in the folate metabolic pathway. Embryos exposed to high doses of MTX exhibited developmental arrest prior to early segmentation. Lower doses of MTX resulted in embryos with a shortened anterior-posterior axis and cardiac defects: linear heart tubes or incomplete cardiac looping. Inhibition of dhfr mRNA with antisense morpholino oligonucleotides resulted in embryonic lethality. One function of the folate pathway is to provide essential one-carbon units for dTMP synthesis, a rate-limiting step of DNA synthesis. After 24?hours of exposure to high levels of MTX, mutant embryos continue to incorporate the thymidine analog BrdU. However, additional experiments indicate that these embryos have fewer mitotic cells, as assayed with phospho-histone H3 antibodies, and that treated embryos have perturbed cell cycles. Conclusions Our studies demonstrate that human and zebrafish utilize similar one-carbon pathways. Our data indicate that folate metabolism is essential for early zebrafish development. Zebrafish studies of the folate pathway and its deficiencies could provide insight into the underlying etiology of human birth defects and the natural role of folate in development. PMID:22480165



Intestinal absorption of different types of folate in healthy subjects with an ileostomy  

Microsoft Academic Search

Our knowledge on the absorption of folate is incomplete. The deconjugation process as a poss- ible limiting factor in the absorption of folates was investigated. The study also attempted to validate the use of the area under the serum response curve (AUC) from food compared with folic acid as a proxy variable for food folate bioavailability. Folate absorption was deter-

Erik J. M. Konings; Freddy J. Troost; Jacqueline J. M. Castenmiller; Brandt van den Piet A; Wim H. M. Saris



Influence of processing on total, monoglutamate and polyglutamate folate contents of leeks, cauliflower, and green beans  

Microsoft Academic Search

Bioavailability of dietary folate might be impaired by the polyglutamate chain to which ~70?f dietary folates are bound. This chain must be removed enzymatically in the intestine before folate is absorbed as a monoglutamate. To increase formation of monoglutamate folate in vegetables, the vegetables were subjected to various processing treatments. Treatments included freezing (-18 C, 16 h) and thawing (4

Alida Melse-Boonstra; Petra Verhoef; Erik J. M. Konings; Marijke van Dusseldorp; Ariette Matser; Peter C. H. Hollman; Saskia Meyboom; Frans J. Kok; Clive E. West



Epithelial cell folate depletion occurs in neoplastic but not adjacent normal colon mucosa  

Microsoft Academic Search

BACKGROUND & AIMS: Restricted folate supply is associated with the development of carcinoma, and folate supplements have a protective effect in colorectal carcinoma. This effect may be mediated through correction of local folate deficiency. The aim of this study was to define the folate content of neoplastic colonic epithelial cells and its relation to that of adjacent normal tissue and

J Meenan; E O'Hallinan; J Scott; DG Weir



A-CED How Much Folate?  

NSDL National Science Digital Library

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Sara's doctor tells her she needs between 400 and 800 milligrams of folate per day, with part coming from her diet and part coming from a multi-vitamin...


Folate targeted polymeric 'green' nanotherapy for cancer  

NASA Astrophysics Data System (ADS)

The concept of 'green' chemotherapy by employing targeted nanoparticle mediated delivery to enhance the efficacy of phytomedicines is reported. Poly (lactide-co-glycolide) (PLGA) nanoparticles encapsulating a well known nutraceutical namely, grape seed extract (GSE)—'NanoGSE'—was prepared by a nanoprecipitation technique. The drug-loaded nanoparticles of size ~ 100 nm exhibited high colloidal stability at physiological pH. Molecular receptor targeting of this nanophytomedicine against folate receptor over-expressing cancers was demonstrated in vitro by conjugation with a potential cancer targeting ligand, folic acid (FA). Fluorescence microscopy and flow cytometry data showed highly specific cellular uptake of FA conjugated NanoGSE on folate receptor positive cancer cells. Studies were also conducted to investigate the efficiency of targeted (FA conjugated) versus non-targeted (non-FA conjugated) nanoformulations in causing cancer cell death. The IC50 values were lowered by a factor of ~ 3 for FA-NanoGSE compared to the free drug, indicating substantially enhanced bioavailability to the tumor cells, sparing the normal ones. Receptor targeting of FA-NanoGSE resulted in a significant increase in apoptotic index, which was also quantified by flow cytometry and fluorescence microscopy. This in vitro study provides a basis for the use of nanoparticle mediated delivery of anticancer nutraceuticals to enhance bioavailability and effectively target cancer by a 'green' approach.

Narayanan, Sreeja; Binulal, N. S.; Mony, Ullas; Manzoor, Koyakutty; Nair, Shantikumar; Menon, Deepthy



[Metafolin--alternative for folate deficiency supplementation in pregnant women].  


Proper folate supplementation is required in order to ensure proper folate concentration in the organism, and consequently to prevent the development of numerous complications in general population and pregnant women. Metafolin (stable calcium salt of L-5-methyltetrahydrofolate acid, L-5-MTHF) is the most active form of reduced folate circulating in plasma, which directly enters the metabolic process of folate. After administration metafolin shows optimum absorption, comparable or higher bioavailability as well as physiological activity when compared to folic acid. Metafolin supplementation is effective in decreasing plasma homocysteine, as well as increasing folate in plasma and erythrocytes, in pregnant and breastfeeding women or those who wish to conceive. In addition, metafolin administration omits the multistage process of reduction before entering the folate cell cycle, as well as a possible deficiency of activity of enzymes participating in the reduction of folate process in the intestine epithelium (DHFR and MTHFR enzymes). So far no potential adverse and toxic effects of metafolin management have been reported. The published findings require confirmation in larger groups of patients and an additional analysis of the presence of particular genotypes of 677C > T polymorphism of the MTHFR gene. Analysis of the recent literature reposts suggests that metafolin could be an effective and safe alternative to folic acid supplementation and could effectively prevent complications in pregnancy and series birth defects in fetuses and newborns. PMID:24032278

Seremak-Mrozikiewicz, Agnieszka



Structural basis for molecular recognition of folic acid by folate receptors.  


Folate receptors (FR?, FR? and FR?) are cysteine-rich cell-surface glycoproteins that bind folate with high affinity to mediate cellular uptake of folate. Although expressed at very low levels in most tissues, folate receptors, especially FR?, are expressed at high levels in numerous cancers to meet the folate demand of rapidly dividing cells under low folate conditions. The folate dependency of many tumours has been therapeutically and diagnostically exploited by administration of anti-FR? antibodies, high-affinity antifolates, folate-based imaging agents and folate-conjugated drugs and toxins. To understand how folate binds its receptors, we determined the crystal structure of human FR? in complex with folic acid at 2.8?Å resolution. FR? has a globular structure stabilized by eight disulphide bonds and contains a deep open folate-binding pocket comprised of residues that are conserved in all receptor subtypes. The folate pteroate moiety is buried inside the receptor, whereas its glutamate moiety is solvent-exposed and sticks out of the pocket entrance, allowing it to be conjugated to drugs without adversely affecting FR? binding. The extensive interactions between the receptor and ligand readily explain the high folate-binding affinity of folate receptors and provide a template for designing more specific drugs targeting the folate receptor system. PMID:23851396

Chen, Chen; Ke, Jiyuan; Zhou, X Edward; Yi, Wei; Brunzelle, Joseph S; Li, Jun; Yong, Eu-Leong; Xu, H Eric; Melcher, Karsten



Utilizing the folate receptor for active targeting of cancer nanotherapeutics  

PubMed Central

The development of specialized nanoparticles for use in the detection and treatment of cancer is increasing. Methods are being proposed and tested that could target treatments more directly to cancer cells, which could lead to higher efficacy and reduced toxicity, possibly even eliminating the adverse effects of damage to the immune system and the loss of quick replicating cells. In this mini-review we focus on recent studies that employ folate nanoconjugates to target the folate receptor. Folate receptors are highly overexpressed on the surface of many tumor types. This expression can be exploited to target imaging molecules and therapeutic compounds directly to cancerous tissues. PMID:23240070

Zwicke, Grant L.; Mansoori, G. Ali; Jeffery, Constance J.



Expression of folate receptors in nasopharyngeal and laryngeal carcinoma and folate receptor-mediated endocytosis by molecular targeted nanomedicine.  


Immunohistochemistry and an immunofluorescence technique was used to detect folate receptor expression in tissue samples and cell lines of head and neck squamous carcinoma, including 20 tissue samples of nasopharyngeal carcinoma, 16 tissue samples of laryngeal carcinoma, and HNE-1, HNE-2, CNE-1, CNE-2, SUNE-1, 5-8F, and Hep-2 cell lines. Iron staining, electron microscopy, and magnetic resonance imaging were used to observe endocytosis of folate-conjugated cisplatin-loaded magnetic nanoparticles (CDDP-FA-ASA-MNP) in cultured cells and transplanted tumors. As shown by immunohistochemistry, 83.3% (30/36) of the head and neck squamous carcinomas expressed the folate receptor versus none in the control group (0/24). Only the HNE-1 and Hep-2 cell lines expressed the folate receptor, and the other five cell lines did not. Endocytosis of CDDP-FA-ASA-MNP was seen in HNE-1 and Hep-2 cells by iron staining and electron microscopy. A similar result was seen in transplanted tumors in nude mice. Magnetic resonance imaging showed low signal intensity of HNE-1 cells and HNE-1 transplanted tumors on T2-weighted images after uptake of CDDP-FA-ASA-MNP, and this was not seen in CNE-2 transplanted tumors. In conclusion, head and neck squamous carcinoma cell strongly expressed the folate receptor, while normal tissue did not. The folate receptor can mediate endocytosis of folate-conjugated anticancer nanomedicines, and lays the foundation for molecular targeted treatment of cancer. PMID:23874095

Xie, M; Zhang, H; Xu, Y; Liu, T; Chen, S; Wang, J; Zhang, T



Intestinal folate binding protein (FBP) and folate absorption in the suckling rat  

SciTech Connect

The folate in milk is bound to high affinity FBPs but it is unknown whether this binding affects intestinal transport of milk folate in the suckling rat. The authors examined the FBP activity of segments of the GI tract in fed and fasting states. Under fed conditions, the FBP activity in the mucosa of the stomach and proximal small intestine were similar (0.28 and 0.32 pMole folic acid binding/mg protein, N.S.). Both demonstrated less activity than the mucosa of the distal small intestine (1.31 pMole/mg protein, P < .001). A 6 hr fast produced no change in the FBP activity in the stomach or proximal small intestine but resulted in a 42% decrease in the distal small intestine (p < .01). Intestinal transport of unbound and FB-bound H/sup 3/pteryolmonoglutamate (H/sup 3/PGA) was examined in suckling rats by the intestinal loop model. Unbound H/sup 3/PGA demonstrated greater lumenal disappearance in the proximal segment of the small intestine compared to the distal segment (79% vs. 56%, P < .001) whereas the bound H/sup 3/PGA demonstrated greater lumenal disappearance in the distal segment (36% vs. 21%, p < .005). That porton of FBP activity in the distal small intestine that disappears with fasting may represent FBP absorbed from the lumen of the intestine. The FBP-bound folate in milk appears to be absorbed in the suckling rat by a mechanism that favors the distal small intestine and is different from the mechanism responsible for absorption of the unbound folate.

Mason, J.B.; Selhub, J.



Cellulose Biosynthesis in Enterobacteriaceae  

Microsoft Academic Search

Distinct bacterial species belonging to the family of Enterobacteriaceae harbor a characteristic cellulose biosynthesis operon (bcs). A regulatory network for cellulose biosynthesis has been identified in Salmonella typhimurium. Transcription of the bcs operon is constitutive, while cellulose biosynthesis is activated on the post-transcriptional level by AdrA, a GGDEF domain containing protein. AdrA is under the tight positive control of the

Ute Römling


Oral contraceptives: effect of folate and vitamin B12 metabolism.  

PubMed Central

Women who use oral contraceptives have impaired folate metabolism as shown by slightly but significantly lower levels of folate in the serum and the erythrocytes and an increased urinary excretion of formiminoglutamic acid. The vitamin B12 level in their serum is also significantly lower than that of control groups. However, there is no evidence of tissue depletion of vitamin B12 associated with the use of oral contraceptives. The causes and clinical significance of the impairment of folate and vitamin B12 metabolism in these women is discussed in this review of the literature. Clinicians are advised to ensure that women who shop taking "the pill" because they wish to conceive have adequate folate stores before becoming pregnant. PMID:7037144

Shojania, A. M.



[The significance of folate metabolism in complications of pregnant women].  


Proper metabolism of folates has a crucial role for body homeostasis. Folate metabolism regulates changing of amino acids (homocysteine and methionine), purine and pyrimidine synthesis and DNA methylation. These whole biochemical processes have significant influence on hematopoietic, cardiovascular and nervous system functions. The disturbances of folate cycle could result in chronic hypertension, coronary artery disease, higher risk of heart infarction, could promote cancers development, and psychic and neurodegenerative diseases. No less important is the connection with complications appearing in pregnant woman (recurrent miscarriages, preeclampsia, fetus hypotrophy intrauterine death, preterm placenta ablation, preterm delivery) and fetus defects (Down syndrome, spina bifida, encephalomeningocele, myelomeningocele). The complex process of folate metabolism requires adequate activity of many enzymes and presence of co-enzymes. A key enzyme in folate metabolism is methylenetetrahydrofolate reductase (MTHFR - methylenetetrahydrofolate reductase), and 677C>T polymorphism of MTHFR gene is connected with lower enzymatic activity In several researches it was indicated that 677C>T MTHFR polymorphism is an independent factor influencing homocysteine concentration in serum, and also folate concentration in serum and red blood cells. Nevertheless, it was also observed the correlation of 677C>T MTHFR polymorphism with Down syndrome, and neural tube defects appearance in fetus. In European populations frequency of mutated 677TT genotype ranges from a few to several percent. Women carriers of 677TT or 677CT MTHFR genotypes are exposed on folate metabolism disturbances and on the consequences of incorrect folate process during pregnancy Nowadays in this group of women folic acid supplementation is widely recommended. In the light of modern knowledge the attention was also focused on the importance of metafolin administration that omitted pathways of folic acid transformation after administration, and in pregnant women certainly is valuable complement of supplementation in this respect. PMID:23819405

Seremak-Mrozikiewicz, Agnieszka



Folate and alcohol consumption and the risk of lung cancer  

SciTech Connect

Because both folate deficiency and alcohol intake have been hypothesized to be lung cancer risk factors, the authors examined the effect of folate and alcohol consumption on risk of lung cancer in a case-control study conducted 1980-1984. Usual dietary intake of 450 histologically confirmed lung cancer cases and 902 controls, all Western New York residents, was ascertained using a modified food frequency questionnaire. Folate intake was not associated with lung cancer risk. After adjusting for age, cigarette smoking, education, and carotene intake, the odds ratio (OR) for the highest category of folate intake was 1.59 in males and 1.34 in females. There was some indication of a protective effect of folate only among women who never smoked. There was a suggestion of a positive association of alcohol intake with lung cancer risk in males, independent of age, education, cigarette smoking, and carotene. Consumers of more than 9 beers per month had an OR of 1.51 compared to non-drinkers. In both sexes, there was an indication of an interaction between beer ingestion and cigarette smoking. While folate intake did not appear to affect risk of lung cancer, the association of alcohol intake with risk independent of cigarette smoking deserves further inquiry.

Bandera, E.V.; Graham, S.; Freudenheim, J.L.; Marshall, J.R.; Haughey, B.P.; Swanson, M.; Brasure, J.; Wilkinson, G. (State Univ. of New York, Buffalo (United States))



The glycophospholipid-linked folate receptor internalizes folate without entering the clathrin-coated pit endocytic pathway  

PubMed Central

The folate receptor, also known as the membrane folate-binding protein, is maximally expressed on the surface of folate-depleted tissue culture cells and mediates the high affinity accumulation of 5- methyltetrahydrofolic acid in the cytoplasm of these cells. Recent evidence suggests that this receptor recycles during folate internalization and that it is anchored in the membrane by a glycosyl- phosphatidylinositol linkage. Using quantitative immunocytochemistry, we now show that (a) this receptor is highly clustered on the cell surface; (b) these clusters are preferentially associated with uncoated membrane invaginations rather than clathrin-coated pits; and (c) the receptor is not present in endosomes or lysosomes. This receptor appears to physically move in and out of the cell using a novel uncoated pit pathway that does not merge with the clathrin-coated pit endocytic machinery. PMID:1968465



Folate and cobalamin modify associations between S-adenosylmethionine and methylated arsenic metabolites in arsenic-exposed Bangladeshi adults.  


Chronic exposure to inorganic arsenic (InAs) through drinking water is a major problem worldwide. InAs undergoes hepatic methylation to form mono- and dimethyl arsenical species (MMA and DMA, respectively), facilitating arsenic elimination. Both reactions are catalyzed by arsenic (+3 oxidation state) methyltransferase (AS3MT) using S-adenosylmethionine (SAM) as the methyl donor, yielding the methylated product and S-adenosylhomocysteine (SAH), a potent product-inhibitor of AS3MT. SAM biosynthesis depends on folate- and cobalamin-dependent one-carbon metabolism. With the use of samples from 353 participants in the Folate and Oxidative Stress Study, our objective was to test the hypotheses that blood SAM and SAH concentrations are associated with arsenic methylation and that these associations differ by folate and cobalamin nutritional status. Blood SAM and SAH were measured by HPLC. Arsenic metabolites in blood and urine were measured by HPLC coupled to dynamic reaction cell inductively coupled plasma MS. In linear regression analyses, SAH was not associated with any of the arsenic metabolites. However, log(SAM) was negatively associated with log(% urinary InAs) (?: -0.11; 95% CI: -0.19, -0.02; P = 0.01), and folate and cobalamin nutritional status significantly modified associations between SAM and percentage of blood MMA (%bMMA) and percentage of blood DMA (%bDMA) (P = 0.02 and P = 0.01, respectively). In folate- and cobalamin-deficient individuals, log(SAM) was positively associated with %bMMA (?: 6.96; 95% CI: 1.86, 12.05; P < 0.01) and negatively associated with %bDMA (?: -6.19; 95% CI: -12.71, 0.32; P = 0.06). These findings suggest that when exposure to InAs is high, and methyl groups are limiting, SAM is used primarily for MMA synthesis rather than for DMA synthesis, contributing additional evidence that nutritional status may explain some of the interindividual differences in arsenic metabolism and, consequently, susceptibility to arsenic toxicity. PMID:24598884

Howe, Caitlin G; Niedzwiecki, Megan M; Hall, Megan N; Liu, Xinhua; Ilievski, Vesna; Slavkovich, Vesna; Alam, Shafiul; Siddique, Abu B; Graziano, Joseph H; Gamble, Mary V



Methylenetetrahydrofolate reductase (MTHFR) c677t gene variant modulates the homocysteine folate correlation in a mild folate-deficient population  

Microsoft Academic Search

Background: A large body of evidence links plasma concentrations of homocysteine and cardiovascular disease. Several genetic and environmental variables may modulate such relationship. We investigated the influence of methylenetetrahydrofolate reductase (MTHFR) gene variants C677T, A1298C, and T1317C on homocysteine, folate, and cobalamin concentrations in a sample of individuals from a mild folate deficiency population to better clarify the complex interactions

Alexandre C. Pereira; Isolmar Tadeu Schettert; Antônio Alberto F. Morandini Filho; Elvira Maria Guerra-Shinohara; José E. Krieger



Biomarkers of folate status in NHANES: a roundtable summary123456  

PubMed Central

A roundtable to discuss the measurement of folate status biomarkers in NHANES took place in July 2010. NHANES has measured serum folate since 1974 and red blood cell (RBC) folate since 1978 with the use of several different measurement procedures. Data on serum 5-methyltetrahydrofolate (5MTHF) and folic acid (FA) concentrations in persons aged ?60 y are available in NHANES 1999–2002. The roundtable reviewed data that showed that folate concentrations from the Bio-Rad Quantaphase II procedure (Bio-Rad Laboratories, Hercules, CA; used in NHANES 1991–1994 and NHANES 1999–2006) were, on average, 29% lower for serum and 45% lower for RBC than were those from the microbiological assay (MA), which was used in NHANES 2007–2010. Roundtable experts agreed that these differences required a data adjustment for time-trend analyses. The roundtable reviewed the possible use of an isotope-dilution liquid chromatography–tandem mass spectrometry (LC-MS/MS) measurement procedure for future NHANES and agreed that the close agreement between the MA and LC-MS/MS results for serum folate supported conversion to the LC-MS/MS procedure. However, for RBC folate, the MA gave 25% higher concentrations than did the LC-MS/MS procedure. The roundtable agreed that the use of the LC-MS/MS procedure to measure RBC folate is premature at this time. The roundtable reviewed the reference materials available or under development at the National Institute of Standards and Technology and recognized the challenges related to, and the scientific need for, these materials. They noted the need for a commutability study for the available reference materials for serum 5MTHF and FA. PMID:21593502

Pfeiffer, Christine M; Phinney, Karen W; Fazili, Zia; Lacher, David A; Bailey, Regan L; Blackmore, Sheena; Bock, Jay L; Brody, Lawrence C; Carmel, Ralph; Curtin, L Randy; Durazo-Arvizu, Ramon A; Eckfeldt, John H; Green, Ralph; Gregory, Jesse F; Hoofnagle, Andrew N; Jacobsen, Donald W; Jacques, Paul F; Molloy, Anne M; Massaro, Joseph; Mills, James L; Nexo, Ebba; Rader, Jeanne I; Selhub, Jacob; Sempos, Christopher; Shane, Barry; Stabler, Sally; Stover, Patrick; Tamura, Tsunenobu; Tedstone, Alison; Thorpe, Susan J; Johnson, Clifford L; Picciano, Mary Frances



Mechanism of folate transport across the human colonic basolateral membrane.  


Previous studies from our laboratory have demonstrated the existence of a folate transporter in the human colonic apical membranes. The current studies were undertaken to examine the possible presence and function of a folate carrier in the human colonic basolateral membrane vesicles (BLMV). BLMV were purified from mucosal scrapings of colons of organ donors by a Percoll-density gradient centrifugation technique, and uptake studies were performed using a rapid filtration technique. Our results on [(3)H]Pte-Glu uptake are summarized as follows: 1) uptake was sensitive to osmolarity of the incubation medium; 2) Na(+) removal from the incubation medium did not affect folate uptake into BLMV; 3) uptake was significantly increased with decreasing incubation buffer pH from 8 to 4; 4) uptake demonstrated saturation kinetics with an apparent Michaelis constant of 9.6 +/- 0.48 microM and a maximal velocity of 8.10 +/- 0.36 pmol x mg protein(-1) x 10 s(-1); 5) uptake was markedly inhibited by the structural analog methotrexate (inhibitory constant = 8.28 +/- 1.0 microM); 6) uptake into BLMV demonstrated a trans-stimulation phenomenon; 7) anion exchange inhibitors DIDS and SITS significantly inhibited folate uptake; and 8) uptake was potential-insensitive, as voltage clamping of vesicles or making them inside positive with K(+)/valinomycin failed to influence folate uptake. Western blot analysis using purified human colonic basolateral membrane preparations and specific polyclonal antibodies against the human reduced folate carrier (hRFC) has shown expression of the hRFC protein at this membrane domain. These data demonstrate the existence of a pH-dependent, DIDS-sensitive, electroneutral, carrier-mediated mechanism for folate transport across the human colonic basolateral membranes. PMID:11408255

Dudeja, P K; Kode, A; Alnounou, M; Tyagi, S; Torania, S; Subramanian, V S; Said, H M



Biomarkers of folate status in NHANES: a roundtable summary.  


A roundtable to discuss the measurement of folate status biomarkers in NHANES took place in July 2010. NHANES has measured serum folate since 1974 and red blood cell (RBC) folate since 1978 with the use of several different measurement procedures. Data on serum 5-methyltetrahydrofolate (5MTHF) and folic acid (FA) concentrations in persons aged ?60 y are available in NHANES 1999-2002. The roundtable reviewed data that showed that folate concentrations from the Bio-Rad Quantaphase II procedure (Bio-Rad Laboratories, Hercules, CA; used in NHANES 1991-1994 and NHANES 1999-2006) were, on average, 29% lower for serum and 45% lower for RBC than were those from the microbiological assay (MA), which was used in NHANES 2007-2010. Roundtable experts agreed that these differences required a data adjustment for time-trend analyses. The roundtable reviewed the possible use of an isotope-dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS) measurement procedure for future NHANES and agreed that the close agreement between the MA and LC-MS/MS results for serum folate supported conversion to the LC-MS/MS procedure. However, for RBC folate, the MA gave 25% higher concentrations than did the LC-MS/MS procedure. The roundtable agreed that the use of the LC-MS/MS procedure to measure RBC folate is premature at this time. The roundtable reviewed the reference materials available or under development at the National Institute of Standards and Technology and recognized the challenges related to, and the scientific need for, these materials. They noted the need for a commutability study for the available reference materials for serum 5MTHF and FA. PMID:21593502

Yetley, Elizabeth A; Pfeiffer, Christine M; Phinney, Karen W; Fazili, Zia; Lacher, David A; Bailey, Regan L; Blackmore, Sheena; Bock, Jay L; Brody, Lawrence C; Carmel, Ralph; Curtin, L Randy; Durazo-Arvizu, Ramón A; Eckfeldt, John H; Green, Ralph; Gregory, Jesse F; Hoofnagle, Andrew N; Jacobsen, Donald W; Jacques, Paul F; Molloy, Anne M; Massaro, Joseph; Mills, James L; Nexo, Ebba; Rader, Jeanne I; Selhub, Jacob; Sempos, Christopher; Shane, Barry; Stabler, Sally; Stover, Patrick; Tamura, Tsunenobu; Tedstone, Alison; Thorpe, Susan J; Coates, Paul M; Johnson, Clifford L; Picciano, Mary Frances




EPA Science Inventory

Dietary folate deficiency enhances arsenic-induced micronucleus formation in mice. Folate deficiency increases background levels ofDNA damage and can enhance the mutagenicity of chemical agents. Duplicate experiments were performed to investigate the effect of dietary...


RESEARCH ARTICLE Open Access The causal effect of red blood cell folate on  

E-print Network

Background: Investigation of the biological mechanism by which folate acts to affect fetal development can-14]. An understand- ing of the biological mechanism by which folate acts to affect fetal development can inform

Kaski, Samuel


Controlled release of folic acid through liquid-crystalline folate nanoparticles.  


The present study explores folate nanoparticles as nano-carriers for controlled drug delivery. Cross-linked nanoparticles of liquid crystalline folates are composed of ordered stacks. This paper shows that the folate nanoparticles can be made with less than 5% loss in folate ions. In addition, this study shows that folate nanoparticles can disintegrate in a controlled fashion resulting in controlled release of the folate ions. Release can be controlled by the size of nanoparticles, the extent of cross-linking and the choice of cross-linking cation. The effect of different factors like agitation, pH, and temperature on folate release was also studied. Studies were also carried out to show the effect of release medium and role of ions in the release medium on disruption of folate assembly. PMID:25280715

Misra, Rahul; Katyal, Henna; Mohanty, Sanat



The monomeric state of the proton-coupled folate transporter represents the functional unit in the plasma membrane.  


Folic acid is an essential vitamin required for de novo biosynthesis of nucleotides and amino acids. The proton-coupled folate transporter (PCFT; SLC46A1) has been identified as the major contributor for intestinal folate uptake. It is also involved in folate transport across the blood-brain barrier and into solid tumors. PCFT belongs to the major facilitator superfamily. Major facilitator superfamily members can exist in either monomeric or homo-oligomeric form. Here, we utilized blue native polyacrylamide gel electrophoresis (BN/PAGE) and crosslinking with bi-functional chemicals to investigate the quaternary structure of human PCFT after heterologous expression in Xenopus laevis oocytes and CHO cells. PCFT was expressed in the plasma membrane in both expression systems. The functionality of the utilized PCFT construct was confirmed in oocytes by folic acid induced currents at acidic pH. For both the oocyte and CHO expression system [(3)H]folic acid uptake studies indicated that PCFT was functional. To analyze the oligomeric state of PCFT in the plasma membrane, plasma membranes were isolated by polymerization with colloidal silica and polyacrylic acid and subsequent centrifugation. The digitonin-solubilized non-denatured PCFT migrated during BN/PAGE as a monomer, as judged by comparison with a membrane protein (5-HT(3A) receptor) of known pentameric assembly that was used to create a molecular sizing ladder. The chemical crosslinkers glutaraldehyde and dimethyl adipimidate were not able to covalently link potential higher order PCFT structures to form oligomers that were stable following SDS treatment. Together, our results demonstrate that plasma-membrane PCFT functions as a monomeric protein. PMID:23601781

Duddempudi, Phaneendra K; Nakashe, Prachi; Blanton, Michael P; Jansen, Michaela



Measurement of endosome pH following folate receptor-mediated endocytosis  

Microsoft Academic Search

Free folic acid is believed to enter some cells by folate receptor-mediated endocytosis at membrane invaginations termed caveolae. Folate conjugated macromolecules also enter cells by folate receptor-mediated endocytosis, but their site of entry has never been conclusively identified. In this paper, we show that internalization of folate-macromolecule conjugates by receptor-bearing KB cells can be blocked by agents that specifically inhibit

Robert J. Lee; Susan Wang; Philip S. Low



Folate-mediated tumor cell targeting of liposome-entrapped doxorubicin in vitro  

Microsoft Academic Search

Receptors for the vitamin folic acid are frequently overexpressed on epithelial cancer cells. To examine whether this overexpression might be exploited to specifically deliver liposome-encapsulated drug molecules in vitro, folate-targeted liposomes were prepared by incorporating 0.1 mol% of a folate-polyethyleneglycol-distearoylphosphatidylethanolamine (folate-PEG-DSPE) construct into the lipid bilayer, and were loaded with doxorubicin (DOX), an anti-cancer drug. Uptake of folate-PEG-liposomal DOX by

Robert J Lee; Philip S Low



Folate-metabolizing gene variants and pregnancy outcome of IVF.  


There is growing evidence that folate status and variation in folate-metabolizing genes are involved in female reproductive functions. This study evaluated the influence of maternal blood folate, vitamin B(12), homocysteine and 10 folate pathway gene variants on IVF outcome. Also, the prevalence of these polymorphisms was compared in 439 female IVF patients and 225 fertile controls. MTHFR 677 CT heterozygotes had a higher proportion of good-quality embryos and an increased chance of pregnancy. MTHFR 1793 GA heterozygosity was associated with a lower percentage of previously failed IVF treatments. Heterozygosity for FOLR1 1816 C/delC and 1841 G/A was associated with a raised risk of pregnancy loss. The CTH 1208 GT genotype was associated with an increased chance of pregnancy and a smaller number of previously failed IVF cycles and the genotype frequency was lower in IVF patients with three or more previously failed IVF treatments compared with fertile controls. SLC19A1 80 GA heterozygotes had a decreased number of previously failed IVF treatments and were more prevalent among fertile controls. In conclusion, polymorphisms in folate-metabolizing genes may affect ovarian stimulation and pregnancy outcome of IVF, and heterozygous individuals, rather than the wild-type homozygotes, appeared to have more favourable outcomes. PMID:21507721

Laanpere, M; Altmäe, S; Kaart, T; Stavreus-Evers, A; Nilsson, T K; Salumets, A



Synthesis and activity of a folate targeted monodisperse PEG camptothecin conjugate.  


A folate targeted camptothecin small molecule drug conjugate (SMDC) was synthesized using a monodisperse PEG spacer linked to folate via a releasable disulfide carbonate linker. Cell cytotoxicity in human KB cells exhibited an IC50 of 6nM. Importantly, activity of the prodrug was blocked by excess folate, demonstrating receptor-mediated celluar uptake of the PEG conjugate. PMID:24064501

Henne, Walter A; Kularatne, Sumith A; Hakenjos, John; Carron, Joshua D; Henne, Kristene L



Intracellular Trafficking and Membrane Targeting Mechanisms of the Human Reduced Folate Carrier in Mammalian Epithelial  

E-print Network

bacterially synthesized folate in the large intestine (3, 4). Thereafter, folate is distributed into different­6). The RFC is also involved in intestinal absorption of folate from the small and large intes- tine (5 by intestinal absorption. Absorption occurs from both dietary sources in the small intestine and from

Marchant, Jonathan


Expression of Folate Receptor a in the Mammalian Retinol Pigmented Epithelium and Retina  

Microsoft Academic Search

PURPOSE. Folic acid is essential for DNA, RNA, and protein synthesis, and deficiencies in folate can lead to nutritional amblyopia and optic neuropathy. The transport of folate from the choroidal blood supply to the retina is only now beginning to be understood. The reduced-folate transporter was reported recently to be present in cultured human retinal pigment epithelial (RPE) cells and

Sylvia B. Smith; Ramesh Kekuda; Xiaolin Gu; Christy Chancy; Simon J. Conway; Vadivel Ganapathy


Folate and Thiamine Transporters mediated by Facilitative Carriers (SLC19A1-3 and SLC46A1) and Folate Receptors  

PubMed Central

The reduced folate carrier (RFC,SLC19A1), thiamine transporter-1 (ThTr1,SLC19A2) and thiamine transporter-2 (ThTr2,SLC19A3) evolved from the same family of solute carriers. SLC19A1 transports folates but not thiamine. SLC19A2 and SLC19A3 transport thiamine but not folates. SLC19A1 and SLC19A2 deliver their substrates to systemic tissues; SLC19A3 mediates intestinal thiamine absorption. The proton-coupled folate transporter (PCFT,SLC46A1) is the mechanism by which folates are absorbed across the apical-brush-border membrane of the proximal small intestine. Two folate receptors (FOLR1 and FOLR2) mediate folate transport across epithelia by an endocytic process. Folate transporters are routes of delivery of drugs for the treatment of cancer and inflammatory diseases. There are autosomal recessive disorders associated with mutations in genes encoded for SLC46A1 (hereditary folate malabsorption), FOLR1 (cerebral folate deficiency), SLC19A2 (thiamine-responsive megaloblastic anemia), and SLC19A3 (biotin-responsive basal ganglia disease). PMID:23506878

Zhao, Rongbao; Goldman, I. David



Moderate folate depletion modulates the expression of selected genes involved in cell cycle, intracellular signaling and folate uptake in human colonic epithelial cell lines.  


Folate deficiency may affect gene expression by disrupting DNA methylation patterns or by inducing base substitution, DNA breaks, gene deletions and gene amplification. Changes in expression may explain the inverse relationship observed between folate status and risk of colorectal cancer. Three cell lines derived from the normal human colon, HCEC, NCM356 and NCM460, were grown for 32-34 days in media containing 25, 50, 75 or 150 nM folic acid, and the expression of genes involved in cell-cycle checkpoints, intracellular signaling, folate uptake and cell adhesion and migration was determined. Expression of Folate Receptor 1 was increased with decreasing media folate in all cell lines, as was p53, p21, p16 and beta-catenin. With decreasing folate, the expression of both E-cadherin and SMAD-4 was decreased in NCM356. APC was elevated in NCM356 but unchanged in the other lines. No changes in global methylation were detected. A significant increase in p53 exon 7-8 strand breaks was observed with decreasing folate in NCM460 cells. The changes observed are consistent with DNA damage-induced activation of cell-cycle checkpoints and cellular adaptation to folate depletion. Folate-depletion-induced changes in the Wnt/APC pathway as well as in genes involved in cell adhesion, migration and invasion may underlie observed relationships between folate status and cancer risk. PMID:17681772

Crott, Jimmy W; Liu, Zhenhua; Keyes, Mary K; Choi, Sang-Woon; Jang, Hyeran; Moyer, Mary P; Mason, Joel B



Moderate folate depletion modulates the expression of selected genes involved in cell cycle, intracellular signaling and folate uptake in human colonic epithelial cell lines  

PubMed Central

Folate deficiency may affect gene expression by disrupting DNA methylation patterns or by inducing base substitution, DNA breaks, gene deletions and gene amplification. Changes in expression may explain the inverse relationship observed between folate status and risk of colorectal cancer. Three cell lines derived from the normal human colon, HCEC, NCM356 and NCM460, were grown for 32–34 days in media containing 25, 50, 75 or 150 nM folic acid, and the expression of genes involved in cell-cycle checkpoints, intracellular signaling, folate uptake and cell adhesion and migration was determined. Expression of Folate Receptor 1 was increased with decreasing media folate in all cell lines, as was p53, p21, p16 and ?-catenin. With decreasing folate, the expression of both E-cadherin and SMAD-4 was decreased in NCM356. APC was elevated in NCM356 but unchanged in the other lines. No changes in global methylation were detected. A significant increase in p53 exon 7–8 strand breaks was observed with decreasing folate in NCM460 cells. The changes observed are consistent with DNA damage-induced activation of cell-cycle checkpoints and cellular adaptation to folate depletion. Folate-depletion-induced changes in the Wnt/APC pathway as well as in genes involved in cell adhesion, migration and invasion may underlie observed relationships between folate status and cancer risk. PMID:17681772

Crott, Jimmy W.; Liu, Zhenhua; Keyes, Mary K.; Choi, Sang-Woon; Jang, Hyeran; Moyer, Mary P.; Mason, Joel B.



Periconceptional Folate Deficiency and Implications in Neural Tube Defects  

PubMed Central

Nutritional deficiencies are preventable etiological and epigenetic factors causing congenital abnormalities, first cause of infant mortality. Folate deficiency has a well-established teratogenic effect, leading to an increasing risk of neural tube defects. This paper highlights the most recent medical literature about folate deficiency, be it maternal or paternal. It then focuses on associated deficiencies as nutritional deficiencies are multiple and interrelated. Observational and interventional studies have all been consistent with a 50–70% protective effect of adequate women consumption of folates on neural tube defects. Since strategies to modify women's dietary habits and vitamin use have achieved little progress, scientific as well as political effort is mandatory in order to implement global preventive public health strategies aimed at improving the alimentation of women in reproductive age, especially folic acid supplementation. Even with the recent breakthrough of fetal surgery for myelomeningocele, the emphasis should still be on prevention as the best practice rather than treatment of neural tube defects. PMID:22900183

Safi, J.; Joyeux, L.; Chalouhi, G. E.



Clinical recognition and aspects of the cerebral folate deficiency syndromes.  


We characterized cerebral folate deficiency (CFD) as any neuro-psychiatric condition associated with low spinal fluid (CSF) N5-methyltetrahydrofolate (MTHF) but normal folate status outside the central nervous system (CNS). The commonest cause underlying CFD syndromes is the presence of serum autoantibodies of the blocking type directed against folate receptor-? (FR?) attached to the plasma-side of choroid plexus epithelial cells. Blocking FR antibodies inhibit MTHF transport across the choroid plexus. Serum titers of FR antibodies may fluctuate significantly over time. Less frequent causes of CFD are FOLR-1 mutations, mitochondrial disorders and inborn errors affecting folate metabolism. Maternal FR antibodies have been associated with neural tube defects while the presence of FR antibodies in either one or both parents increases the risk of an offspring with infantile autism. Recognizable CFD syndromes attributed to FR-antibodies in childhood are infantile-onset CFD presenting 4-6 months after birth, infantile autism with neurological deficits, and a spastic ataxic syndrome from the age of 1 year, while progressive dystonic or schizophrenic syndromes develop during adolescence. FR autoantibodies are frequently found in autism spectrum disorders, in an Aicardi-Goutières variant and in Rett syndrome. The heterogeneous phenotype of CFD syndromes might be determined by different ages of onset and periods when FR autoantibodies are generated with consequent CNS folate deficiency. Folate deficiency during various critical stages of fetal and infantile development affects structural and functional refinement of the brain. Awareness of CFD syndromes should lead to early detection, diagnosis and improved prognosis of these potentially treatable group of autoimmune and genetically determined conditions. PMID:23314536

Ramaekers, Vincent; Sequeira, Jeffrey M; Quadros, Edward V



Human liver folylpolyglutamate synthetase: biochemical characterization and interactions with folates and folate antagonists.  


Folylpolyglutamate synthetase (FPGS) was isolated from human liver cytosol by 0-30% (w/v) ammonium sulfate fractionation and characterized biochemically. Using aminopterin (AMT), L-[3H]glutamate and MgATP as cosubstrates, maximal gamma-L-glutamylation activity was observed in the presence of the activators KCl and NaHCO3. ATP and 2-mercaptoethanol were each required for enzyme activity and stability. In the absence of ATP, human liver FPGS rapidly inactivated at 37 degrees C (t1/2 approximately 8 min), whereas FPGS isolated from rabbit liver was significantly more stable (t1/2 = 68 min). Both folates and antifolates were effectively polyglutamylated by the isolated human liver enzyme. Km parameters determined for AMT (Km = 4.3 microM) were similar to those determined for several reduced folates (tetrahydrofolic acid, dihydrofolic acid, and folinic acid; Km = 3-7 microM), while significantly higher Km values were observed for methotrexate (MTX) and 5-methyltetrahydrofolic acid (Km = 50-60 microM) and for folic acid (Km = 100 microM). All of the substrates examined exhibited Vmax values ranging from 30 to 90% of the AMT value (Vmax = 935 pmol product/mg/h). The order of reactivity for these substrates differed from that determined in parallel studies for FPGS isolated from rat and rabbit liver. In the case of AMT and several reduced folates, inhibition of human liver FPGS was observed at substrate concentrations at or above 50-250 microM. FPGS isolated from six individual human livers exhibited highly similar biochemical and kinetic properties, suggesting the presence of the same or at least highly similar enzyme species in each individual, with a five-fold interindividual range in specific activities observed. Comparison of MTX with its higher polyglutamates (MTX-Glu2 to MTX-Glu6) as FPGS substrates indicated a significant decrease in Vmax values with increasing glutamate chain length which was partially compensated for by a corresponding decrease in Km. Consistent with these observations, the isolated enzyme was unable to synthesize polyglutamates higher than MTX-Glu3 when MTX was supplied as substrate, raising the question as to how MTX polyglutamates containing up to five or six gamma-L-glutamate residues are formed in vivo. PMID:3619447

Clarke, L; Waxman, D J




EPA Science Inventory

Arsenic, a human carcinogen found in drinking water supplies throughout the world, is clastogenic in human and rodent cells. An estimated ten percent of Americans are deficient in folate, a methyl donor necessary for normal nucleotide metabolism, DNA synthesis, and DNA methylatio...


Behavioral and neurochemical changes in folate-deficient mice  

Microsoft Academic Search

Weanling mice were fed an amino acid-based diet supplemented with 0 or 11.3 ?mol folic acid\\/kg diet for ? 38 days to study behavior and neurochemistry in folate deficiency. After ? 5 wk, mice fed the unsupplemented diet weighed ? 70% as much those fed the supplemented diet. After 2 wk, mice fed the unsupplemented diet consistently discarded (spilled) more

Sidney M. Gospe; Dorothy W. Gietzen; Philip J. Summers; Jennine M. Lunetta; Joshua W. Miller; Jacob Selhub; William G. Ellis; Andrew J. Clifford



Novel serum-tolerant lipoplexes target the folate receptor efficiently.  


Gene transfer using non-viral vectors is a promising approach for the safe delivery of nucleic acid therapeutics. In this study, we investigate a lipid-based system for targeted gene delivery to malignant cells overexpressing the folate receptor (FR). Cationic liposomes were formulated with and without the targeting ligand folate conjugated to distearoylphosphatidyl ethanolamine polyethylene glycol 2000 (DSPE-PEG2000), the novel cytofectin 3?[N(N(1),N(1)-dimethlaminopropylsuccinamidoethane)-carbamoyl]cholesterol (SGO4), which contains a 13atom, 15Å spacer element, and the helper lipid, dioleoylphosphatidylethanolamine (DOPE). Physicochemical parameters of the liposomes and lipoplexes were obtained by zeta sizing, zeta potential measurement and cryo-TEM. DNA-binding and protection capabilities of liposomes were confirmed by gel retardation assays, EtBr intercalation and nuclease protection assays. The complexes were assessed in an in vitro system for their effect on cell viability using the MTT assay, and gene transfection activity using the luciferase assay in three cell lines; HEK293 (FR-negative), HeLa (FR(+)-positive), KB (FR(++)-positive). Low cytotoxicities were observed in all cell lines, while transgene activity promoted by folate-tagged lipoplexes in FR-positive lines was tenfold greater than that by untargeted constructs and cell entry by folate complexes was demonstrably by FR mediation. These liposome formulations have the design capacity for in vivo application and may therefore be promising candidates for further development. PMID:24769039

Gorle, Sridevi; Ariatti, Mario; Singh, Moganavelli



Research goals for folate and related B vitamin in Europe  

Microsoft Academic Search

In the past decade, the understanding of folate bioavailability, metabolism and related health issues has increased, but several problems remain, including the difficulty of delivering the available knowledge to the populations at risk. Owing to the low compliance of taking folic acid supplements, for example, among women of child-bearing age who could lower the risk of having a baby with

P. M. Finglas; K de Meer; A. Molloy; P. Verhoef; K. Pietrzik; H. J. Powers; D van der Straeten; M. Jagerstad; G. Varela-Moreiras; T van Vliet; R. Havenaar; J. Buttriss; A J A Wright



Folate metabolism and the risk of Down syndrome.  


Folate is an important vitamin that contributes to cell division and growth and is therefore of particular importance during infancy and pregnancy. Folate deficiency has been associated with slowed growth, anaemia, weight loss, digestive disorders and some behavioural issues. Adequate folate intake around the time of conception and early pregnancy can reduce the risk of certain problems including neural tube defects. It has been suggested that certain versions (polymorphisms) of some genes can increase the risk of conceiving a baby with Down syndrome. If this is the case, then people with Down syndrome may be more likely to carry these forms of these genes and to experience associated problems in folate metabolism. Studies to date have found conflicting results, suggesting that these gene variants may be part of a more complex picture. In this issue, a further study reports no association between the presence of a common polymorphism of one of these genes and the risk of having a child with Down syndrome among mothers of Northern Indian origin. This article reviews these challenging findings and looks at where investigations can now go to resolve these issues. PMID:19026278

Patterson, David



Leukoencephalopathies associated with disorders of cobalamin and folate metabolism.  


Disorders of cobalamin and folate intracellular metabolism that result in defective remethylation of homocysteine to methionine are associated with leukodystrophy, whereas disorders of cobalamin transport generally are not. Cobalamin derivatives are needed for only two reactions in man; remethylation of homocysteine to methionine, with methylcobalamin as a cofactor for methionine synthase, and the conversion of methylmalonyl-coenzyme A to succinyl coenzyme A by methylmalonyl-CoA mutase, with adenosylcobalamin as a cofactor. Mutations at various metabolic steps affect the synthesis of adenosylcobalamin (CblA, CblB, and CblD2), methylcobalamin (CblE, CblG, and CblD1), or both of these (CblF, CblD, and CblC). The most common disorder of folate metabolism, 5,10-methylenetetrahydrofolate deficiency, also affects remethylation and presents with leukodystrophy. Pathways of cobalamin and folate metabolism intersect at one site, methionine synthase. Patients with the remethylating disorders present acutely or chronically with significant neurologic, hematologic, vascular, and other symptoms. Circulating levels of cobalamin and folate are usually normal in these disorders, and initial diagnosis is aided by measurement of homocysteine and methylmalonic acid in blood or urine, together with hematologic tests. Current diagnosis is often by newborn screening. These disorders all show autosomal recessive inheritance, and all are treatable, although with variable outcome. PMID:22422209

Wilcken, Bridget



[Direct biosynthesis of ethylene].  


Ethylene is the most widely used petrochemical feedstock globally. The development of bio-ethylene is essential due to limited fossil fuels and rising oil prices. Bio-ethylene is produced primarily by the dehydration of ethanol, but can alternatively be directly produced from ethylene biosynthesis pathways in plants, algae, or microorganisms by using cheap and renewable substrates. This review addressed the biosynthesis of ethylene in plants and microorganisms, the characterization of key enzymes, genetic engineering strategies for ethylene biosynthesis in microorganisms, and evaluated its perspective and successful cases toward the industrial application. The direct production of bio-ethylene from a biological process in situ is promising to supplement and even replace the petrochemical ethylene production. PMID:24432658

Sun, Zhilan; Chen, Yifeng



Aflatoxin biosynthesis: current frontiers.  


Aflatoxins are among the principal mycotoxins that contaminate economically important food and feed crops. Aflatoxin B1 is the most potent naturally occurring carcinogen known and is also an immunosuppressant. Occurrence of aflatoxins in crops has vast economic and human health impacts worldwide. Thus, the study of aflatoxin biosynthesis has become a focal point in attempts to reduce human exposure to aflatoxins. This review highlights recent advances in the field of aflatoxin biosynthesis and explores the functional connection between aflatoxin biosynthesis, endomembrane trafficking, and response to oxidative stress. Dissection of the regulatory mechanisms involves a complete comprehension of the aflatoxin biosynthetic process and the dynamic network of transcription factors that orchestrates coordinated expression of the target genes. Despite advancements in the field, development of a safe and effective multifaceted approach to solve the aflatoxin food contamination problem is still required. PMID:23244396

Roze, Ludmila V; Hong, Sung-Yong; Linz, John E



Xyloglucan and Its Biosynthesis  

PubMed Central

The hemicellulosic polysaccharide xyloglucan (XyG), found in the primary cell walls of most plant tissues, is important for structural organization of the cell wall and regulation of growth and development. Significant recent progress in structural characterization of XyGs from different plant species has shed light on the diversification of XyG during plant evolution. Also, identification of XyG biosynthetic enzymes and examination of their interactions suggests the involvement of a multiprotein complex in XyG biosynthesis. This mini-review presents an updated overview of the diversity of XyG structures in plant taxa and recent findings on XyG biosynthesis. PMID:22737157

Zabotina, Olga A.



Endocytosis of GPI-linked membrane folate receptor-alpha.  


GPI-linked membrane folate receptors (MFRs) have been implicated in the receptor-mediated uptake of reduced folate cofactors and folate-based chemotherapeutic drugs. We have studied the biosynthetic transport to and internalization of MFR isoform alpha in KB-cells. MFR-alpha was synthesized as a 32-kD protein and converted in a maturely glycosylated 36-38-kD protein 1 h after synthesis. 32-kD MFR-alpha was completely soluble in Triton X-100 at 0 degree C. In contrast, only 33% of the 36-38-kD species could be solubilized at these conditions whereas complete solubilization was obtained in Triton X-100 at 37 degrees C or in the presence of saponin at 0 degree C. Similar solubilization characteristics were found when MFR-alpha at the plasma membrane was labeled with a crosslinkable 125I-labeled photoaffinity-analog of folic acid as a ligand. Triton X-100-insoluble membrane domains containing MFR-alpha could be separated from soluble MFR-alpha on sucrose flotation gradients. Only Triton X-100 soluble MFR-alpha was internalized from the plasma membrane. The reduced-folate-carrier, an integral membrane protein capable of translocating (anti-)folates across membranes, was completely excluded from the Triton X-100-resistant membrane domains. Internalized MFR-alpha recycled slowly to the cell surface during which it remained soluble in Triton X-100 at 0 degree C. Using immunoelectron microscopy, we found MFR-alpha along the entire endocytic pathway: in clathrin-coated buds and vesicles, and in small and large endosomal vacuoles. In conclusion, our data indicate that a large fraction, if not all, of internalizing MFR-alpha bypasses caveolae. PMID:8567728

Rijnboutt, S; Jansen, G; Posthuma, G; Hynes, J B; Schornagel, J H; Strous, G J



An investigation of folate-related genetic factors in the determination of birthweight.  


Recent evidence suggests that maternal folate status in early gestation is a significant determinant of infant birthweight. Folate metabolism is known to be controlled by genetic factors, with a number of polymorphic variations in folate metabolising genes identified, several of which have well-documented functional effects. The current study investigated whether folate-related polymorphic variation, in association with low maternal folate status, influences birthweight. Red blood cell (RBC) folate analysis and genotyping of five polymorphisms in folate-related genes [Methylenetetrahydrofolate reductase (MTHFR) 677C>T; MTHFR 1298A>C; cystathionine-beta-synthase (CbetaS) 844ins68bp; serine hydroxymethyltransferase (SHMT) 1420C>T; reduced folate carrier-1 (RFC-1) 80G>A] were undertaken in mothers and infants from 998 pregnancies. These data were analysed in relation to infant birthweight, adjusted for gender and gestational age (z-score). Low maternal RBC folate status was associated with reduced infant birthweight. None of the genetic variants studied showed an independent association with infant birthweight. However, two genetic variants were shown to have a significant effect on birthweight when found in association with low maternal RBC folate status. When individuals with variant genotypes and mothers with folate in the lowest quintile were compared with wild-type individuals and mothers with folate in the highest quintile, the following differences in mean birthweight (z-score) were observed; maternal MTHFR 677C>T (-0.56 [95% CI -1.00, -0.12]P=0.01) and infant CbetaS 844ins68bp (-0.71 [95% CI -1.97, -0.07]P=0.03). The findings of this study suggest that folate-related genetic polymorphisms do not directly influence infant birthweight. However, when placed on a background of deficient maternal nutritional status, they may detrimentally affect fetal growth. PMID:16115288

Relton, Caroline L; Pearce, Mark S; Burn, John; Parker, Louise



Influence of Meal on Plasma Folate and Vitamin B12, by Three Methods - and on Vitamin B6, Homocysteine and Red Blood Cell Folate  

Microsoft Academic Search

Vitamins are brought by meals. Some of them are cofactors in homocysteine metabolism, and, if plasma homo- cysteine values are not known to have a circadian rhythm, little is known about meal influence on blood folate, and vitamins B12 and B6. The aim of this study is to analyze the effect of breakfast and lunch on plasma folate, vitamins B12

Mirande Candito; Bakhouche Houcher; François Roux; Genevieve Potier de Courcy; Anne Caramella; Frederick Berthier; Abdelhamid Aberkane



Development and Pre-clinical Evaluation of New 68Ga-NOTA-folate Conjugates for PET Imaging of Folate Receptor-positive Tumors.  


In an attempt to develop new folate radiotracers with favorable biochemical properties for detecting folate receptor-positive cancers, we synthesized (68)Ga-NOTA- and (68)Ga-NOTAM-folate conjugates using a straightforward and a one-step simple reaction. Radiochemical yields were greater than 95% (decay-corrected) with total synthesis time of less than 20 min. Radiochemical purities were always greater than 98% without high-performance liquid chromatography (HPLC) purification. These synthetic approaches hold considerable promise as a rapid and simple method for (68)Ga-folate conjugate preparation with high radiochemical yield in a short synthesis time. In vitro tests on the KB cell line showed that significant amounts of the radioconjugates were associated with cell fractions. Biodistribution studies in nude mice bearing human KB xenografts, demonstrated a significant tumor uptake and favorable biodistribution profile for (68)Ga-NOTA-folate over the (68)Ga-NOTAM-folate conjugate. The uptake in the tumors was blocked by excess injection of folic acid, suggesting a receptor-mediated process. These results demonstrate that the (68)Ga-NOTA-folate conjugate may be useful as a molecular probe for detection and staging of folate receptor-positive cancers, such as ovarian cancer and their metastasis, as well as monitoring tumor response to treatment. PMID:25368257

Aljammaz, Ibrahim; Al-Otaibi, Basim; Al-Hokbany, Nourah; Amer, Suad; Okarvi, Subhani



Regulation of Starch Biosynthesis  

Microsoft Academic Search

Transient or long-term storage of photosynthate in starch granules can be considered as the last step of eukaryotic photosynthesis. Storage of glucose into structures larger than the size of an individual bacterial cell is slowly uncovering as an exceedingly complex mechanism, which distinguishes the chloroplast from its ancestor prochloron or cyanobacterial-like cell. There is no question that starch biosynthesis has

Steven G. Ball


The biosynthesis of dicoumarol  

PubMed Central

Micro-organisms have been isolated that can utilize o-coumaric acid as a sole carbon source with the subsequent production of 4-hydroxycoumarin and dicoumarol. One of these organisms, Penicillium jenseni, has been used to examine the biosynthesis of dicoumarol. Certain thermophilic fungi have also been found that can convert o-coumaric acid into dicoumarol. PMID:6033758

Bellis, D. M.; Spring, M. S.; Stoker, J. R.



Evaluation of the novel folate receptor ligand [18F]fluoro-PEG-folate for macrophage targeting in a rat model of arthritis  

PubMed Central

Introduction Detection of (subclinical) synovitis is relevant for both early diagnosis and monitoring of therapy of rheumatoid arthritis (RA). Previously, the potential of imaging (sub)clinical arthritis was demonstrated by targeting the translocator protein in activated macrophages using (R)-[11C]PK11195 and positron emission tomography (PET). Images, however, also showed significant peri-articular background activity. The folate receptor (FR)-? is a potential alternative target for imaging activated macrophages. Therefore, the PET tracer [18F]fluoro-PEG-folate was synthesized and evaluated in both in vitro and ex vivo studies using a methylated BSA induced arthritis model. Methods [18F]fluoro-PEG-folate was synthesized in a two-step procedure. Relative binding affinities of non-radioactive fluoro-PEG-folate, folic acid and naturally circulating 5-methyltetrahydrofolate (5-Me-THF) to FR were determined using KB cells with high expression of FR. Both in vivo [18F]fluoro-PEG-folate PET and ex vivo tissue distribution studies were performed in arthritic and normal rats and results were compared with those of the established macrophage tracer (R)-[11C]PK11195. Results [18F]fluoro-PEG-folate was synthesized with a purity >97%, a yield of 300 to 1,700 MBq and a specific activity between 40 and 70 GBq/µmol. Relative in vitro binding affinity for FR of F-PEG-folate was 1.8-fold lower than that of folic acid, but 3-fold higher than that of 5-Me-THF. In the rat model, [18F]fluoro-PEG-folate uptake in arthritic knees was increased compared with both contralateral knees and knees of normal rats. Uptake in arthritic knees could be blocked by an excess of glucosamine-folate, consistent with [18F]fluoro-PEG-folate being specifically bound to FR. Arthritic knee-to-bone and arthritic knee-to-blood ratios of [18F]fluoro-PEG-folate were increased compared with those of (R)-[11C]PK11195. Reduction of 5-Me-THF levels in rat plasma to those mimicking human levels increased absolute [18F]fluoro-PEG-folate uptake in arthritic joints, but without improving target-to-background ratios. Conclusions The novel PET tracer [18F]fluoro-PEG-folate, designed to target FR on activated macrophages provided improved contrast in a rat model of arthritis compared with the accepted macrophage tracer (R)-[11C]PK11195. These results warrant further exploration of [18F]fluoro-PEG-folate as a putative PET tracer for imaging (sub)clinical arthritis in RA patients. PMID:23452511



A humanized mouse model for the reduced folate carrier.  


The ubiquitously expressed reduced folate carrier (RFC) or SLC19A1 is recognized to be an essential transport system for folates in mammalian cells and tissues. In addition to its generalized role as a folate transporter, RFC provides specialized tissue functions including absorption across intestinal/colonic epithelia, transport across the basolateral membrane of renal proximal tubules, transplacental transport of folates, and folate transport across the blood-brain barrier. The human RFC (hRFC) gene is regulated by five major upstream non-coding regions (designated A1/A2, A, B, C, and D), each transcribed from a unique promoter. Altogether, at least 14 distinct hRFC transcripts can be envisaged in which different 5' untranslated regions (UTRs) are fused to a common splice acceptor region (positions -1 to -49) within the first coding exon with a common 1776bp coding sequence. The 5' non-coding regions are characterized by alternate transcription start sites, multiple splice forms, and selective tissue distributions. Alternate 5' UTRs impact mRNA stabilities and translation efficiencies, and result in synthesis of modified hRFC proteins translated from upstream AUGs. In this report, we describe production and characterization of transgenic mice (TghRFC1) containing a functional hRFC gene and of humanized mice in which the mRFC gene is inactivated and an active hRFC gene has been introduced. The mice appear to be healthy and to breed well. Analysis of tissue specificity of expression in both the TghRFC1 and humanized hRFC mice by real-time RT-PCR demonstrates that the hRFC gene is expressed with a specificity closely resembling that seen in human tissues. For the humanized hRFC mice, levels of B and A1/A2 5' UTRs predominated in all mice/tissues, thus resembling results in normal human tissues. Lower levels of A and C 5' UTRs were also detected. The availability of humanized mouse models for hRFC will permit investigators to address critical unanswered questions pertinent to human health and disease. These include the ability to analyze the hRFC gene in vivo, to control dietary and other environmental conditions that may impact levels of gene expression, and to control the genetics of the mice in order to assess the effects of hRFC gene alterations on tissue folate uptake and distribution, none of which can be easily achieved in human populations. PMID:17983788

Patterson, David; Graham, Christine; Cherian, Christina; Matherly, Larry H



Quantification of folate in fruits and vegetables: A fluorescence-based homogeneous assay.  


A high-throughput, homogeneous, fluorescence polarization, and fluorescence intensity assay has been developed for the measurement of folate in fruits and vegetables. This assay is based on the competitive displacement of the fluorescent folate ligands Alexa Fluor (Alexa) 594-folate and Alexa 660-folate from bovine milk folate-binding protein by folates in fruit and vegetable extracts. These fluorescent ligands are employed because their excitation and emission maxima are in regions of the spectrum with minimal autofluorescence in many extracts. Folate-binding protein and Alexa-folate were typically used at concentrations of 0.5 microg/ml and 5nM, respectively, in 20-microl volumes in 384-well microplates. The assay is complete within 100 min. The folate estimate is unaffected by the heterogeneity of polyglutamyl residues that complicates the liquid chromatography-mass spectrometry (LC-MS)-based methods of quantification. In this assay, folic acid had an apparent affinity 2.5-fold greater than 5-methyltetrahydrofolate (5MTHF); therefore, it cannot be used to quantify folate when both natural and synthetic folate are present. 5MTHF-equivalent values were measured in broccoli (240 microg/100g), strawberry (113 microg/100g), white grape (32 microg/100g), orange (44 microg/100g), tomato (12 microg/100g), raspberry (31 microg/100g), banana (29 microg/g), and kiwifruit (36 microg/100g). These data are similar to published values. However, the assay will not detect 5-formyltetrahydrofolate which is a significant constituent of the total folate in lettuce, spinach, carrot, and peppers. PMID:20361923

Martin, Harry; Comeskey, Daniel; Simpson, Robert M; Laing, William A; McGhie, Tony K



Is folate involved in the pathogenesis of inflammatory bowel disease?  


The inflammatory bowel diseases, Crohn's and ulcerative colitis, are common and a significant cause of morbidity. They were rare before the 1930's but the incidence has been increasing in both developed and developing countries. We have recently reported that the incidence in Nova Scotia, the area with one of the highest reported burden globally, is decreasing since 1997. We postulate that this decrease may be due to the addition of folate to cereals. This was mandated in 1998 but the process of fortification began in 1997. There is circumstantial evidence from epidemiology studies that a diet deficient in folate may have contributed to the global rise in these diseases. This hypothesis, if proven to be correct, has important implications for the prevention and treatment of these diseases. PMID:24045091

Leddin, Desmond; Tamim, Hala; Levy, Adrian R



Neurological manifestations of folate transport defect: case report and review of the literature.  


Folate is essential for normal brain development. This report describes a 15-month-old boy who presented with generalized and focal seizures and a decline in mental status. Laboratory tests revealed low folate levels in blood (1.13 nmol/L) and cerebrospinal fluid, accompanied by pancytopenia. Bone marrow aspiration confirmed the presence of megaloblastic anemia. Treatment with high-dose intravenous folinic acid led to normalization of cerebrospinal folate levels. These findings apparently indicate a defect in folic acid transport to the central nervous system. A clinical picture of developmental arrest, seizures, somnolence, and megaloblastic anemia should alert physicians to the possibility of folate deficiency. PMID:17641272

Sofer, Yael; Harel, Liora; Sharkia, Mohamad; Amir, Jacob; Schoenfeld, Tommy; Straussberg, Rachel



Cytogenetic damage induced by folate deficiency in mice is enhanced by caffeine.  

PubMed Central

Folate deficiency in Swiss mice increased the incidence of micronuclei in peripheral blood erythrocytes, indicating increased chromosomal damage in nucleated erythrocyte precursors. Caffeine enhanced the incidence of micronuclei in blood and bone marrow by up to 5-fold in folate-deficient mice at doses that did not significantly alter the micronucleus frequency in the presence of adequate dietary folate. The lower dose of caffeine used in this study (75 mg/kg) approaches doses received by humans who consume large amounts of caffeinated beverages. Since folate deficiency and caffeine consumption are highly prevalent in the human population, the potential for a similar interaction in man should be evaluated. Images PMID:2263647

MacGregor, J T; Schlegel, R; Wehr, C M; Alperin, P; Ames, B N



Obesity affects short-term folate pharmacokinetics in women of childbearing age.  


Maternal folate status and body mass index (BMI) are independent risk factors for neural tube defects (NTD). Population-based studies have identified an inverse association between serum folate and BMI, after adjusting for intake. The objective of this intervention study was to compare the relationship between BMI and the short-term pharmacokinetic response to an oral dose of folic acid. Healthy obese (BMI ?30.0?kg?m(-2); n=16) and normal-weight (BMI 18.5-24.9?kg?m(-2); n=16) women of childbearing age (18-35 years) were administered a single oral dose of folic acid (400??g). Blood samples were collected over a 10-h period to evaluate the serum folate response. Fasting baseline serum folate was lower in the obese group (P=0.005); in contrast, red blood cell folate was higher (P=0.05). Area-under-the-curve for the absorption phase (0-3?h) and peak serum folate concentrations were lower in obese versus normal-weight women (P<0.005). Overall serum folate response (0-10?h) was lower in obese versus normal-weight women (repeated-measures ANOVA, P=0.001). Data suggest body distribution of folate is significantly affected by obesity, and, should pregnancy occur, may reduce the amount of folate available to the developing embryo. These findings provide additional support for a BMI-adjusted folic acid intake recommendation for NTD risk reduction. PMID:23567925

da Silva, V R; Hausman, D B; Kauwell, G P A; Sokolow, A; Tackett, R L; Rathbun, S L; Bailey, L B



A novel hydrolysis-resistant lipophilic folate derivative enables stable delivery of targeted liposomes in vivo  

PubMed Central

Instability of targeting ligand is a roadblock towards successful development of folate targeted liposomes. Folate ligands have been linked to polyethylene glycol (PEG) and cholesterol by an amide bond to form folate-CONH-PEG-CONH-Cholesterol (F-CONH-PEG-CONH-Chol), which is subject to hydrolysis. To increase the stability of folate ligands and promote the long circulation and targeting effects, we synthesized a chemically stable lipophilic folate derivative, folate-CONH-PEG-NH-Cholesterol (F-CONH-PEG-NH-Chol), where the amide bond was replaced by a C-N bond, to deliver liposomal doxorubicin (Dox). Its physical stability, cellular uptake, cellular toxicity, pharmacokinetics, distribution, anti-tumor efficacy, and cardiac toxicity were investigated. Our results indicate that F-CONH-PEG-NH-Chol conjugated liposomes are taken up selectively by folate receptor-positive HeLa and KB cells. Compared with F-CONH-PEG-CONH-Chol with two carbonate linkages, F-CONH-PEG-NH-Chol better retained its drug entrapment efficiency and folate receptor-targeting activity during prolonged circulation. F-CONH-PEG-NH-Chol thus represents a physically stable and effective ligand for delivering folate receptor-targeted liposomes, with prolonged circulation time and efficient tissue distribution, as well as higher efficacy and less cardiac toxicity. Collectively, these results suggest that this novel conjugate can serve as a promising derivative for the delivery of anti-tumor therapeutic agents.

Huang, Yifei; Yang, Tan; Zhang, Wendian; Lu, Yao; Ye, Peng; Yang, Guang; Li, Bin; Qi, Shibo; Liu, Yong; He, Xingxing; Lee, Robert J; Xu, Chuanrui; Xiang, Guangya



Modeling Folate, One-Carbon Metabolism & DNA Methylation

The goal of this proposal is to create a mathematical model of folate-mediated one-carbon metabolism (FOCM) and its relation to DNA methylation. This model will integrate knowledge of enzyme kinetics, genetics and epigenetics, and nutrition, and will enable us to investigate (1) mechanisms by which dietary factors influence DNA methylation, and (2) increase our understanding of these processes in cancer prevention.


Folate and iron metabolism in patients with tumors and inflammations  

Microsoft Academic Search

Reduced serum concentrations of nutrients like iron, zinc and folates and of albumin and cholesterol are found, as well as\\u000a emaciation, both in malnutrition and in cancer. In patients with leukemia, a depletion of intracellular potassium and hypo-potassemia\\u000a are found in addition. The use of hyperalimentation in cancer was originally based on the concept that too little food is\\u000a the

Peter Reizenstein



Folate receptor targeted alpha-therapy using terbium-149.  


Terbium-149 is among the most interesting therapeutic nuclides for medical applications. It decays by emission of short-range ?-particles (E? = 3.967 MeV) with a half-life of 4.12 h. The goal of this study was to investigate the anticancer efficacy of a 149Tb-labeled DOTA-folate conjugate (cm09) using folate receptor (FR)-positive cancer cells in vitro and in tumor-bearing mice. 149Tb was produced at the ISOLDE facility at CERN. Radiolabeling of cm09 with purified 149Tb resulted in a specific activity of ~1.2 MBq/nmol. In vitro assays performed with 149Tb-cm09 revealed a reduced KB cell viability in a FR-specific and activity concentration-dependent manner. Tumor-bearing mice were injected with saline only (group A) or with 149Tb-cm09 (group B: 2.2 MBq; group C: 3.0 MBq). A significant tumor growth delay was found in treated animals resulting in an increased average survival time of mice which received 149Tb-cm09 (B: 30.5 d; C: 43 d) compared to untreated controls (A: 21 d). Analysis of blood parameters revealed no signs of acute toxicity to the kidneys or liver in treated mice over the time of investigation. These results demonstrated the potential of folate-based ?-radionuclide therapy in tumor-bearing mice. PMID:24633429

Müller, Cristina; Reber, Josefine; Haller, Stephanie; Dorrer, Holger; Köster, Ulli; Johnston, Karl; Zhernosekov, Konstantin; Türler, Andreas; Schibli, Roger



Folate Receptor Targeted Alpha-Therapy Using Terbium-149  

PubMed Central

Terbium-149 is among the most interesting therapeutic nuclides for medical applications. It decays by emission of short-range ?-particles (E? = 3.967 MeV) with a half-life of 4.12 h. The goal of this study was to investigate the anticancer efficacy of a 149Tb-labeled DOTA-folate conjugate (cm09) using folate receptor (FR)-positive cancer cells in vitro and in tumor-bearing mice. 149Tb was produced at the ISOLDE facility at CERN. Radiolabeling of cm09 with purified 149Tb resulted in a specific activity of ~1.2 MBq/nmol. In vitro assays performed with 149Tb-cm09 revealed a reduced KB cell viability in a FR-specific and activity concentration-dependent manner. Tumor-bearing mice were injected with saline only (group A) or with 149Tb-cm09 (group B: 2.2 MBq; group C: 3.0 MBq). A significant tumor growth delay was found in treated animals resulting in an increased average survival time of mice which received 149Tb-cm09 (B: 30.5 d; C: 43 d) compared to untreated controls (A: 21 d). Analysis of blood parameters revealed no signs of acute toxicity to the kidneys or liver in treated mice over the time of investigation. These results demonstrated the potential of folate-based ?-radionuclide therapy in tumor-bearing mice. PMID:24633429

Muller, Cristina; Reber, Josefine; Haller, Stephanie; Dorrer, Holger; Koster, Ulli; Johnston, Karl; Zhernosekov, Konstantin; Turler, Andreas; Schibli, Roger



Nutriepigenetic regulation by folate-homocysteine-methionine axis: a review.  


Although normally folic acid is given during pregnancy, presumably to prevent neural tube defects, the mechanisms of this protection are unknown. More importantly it is unclear whether folic acid has other function during development. It is known that folic acid re-methylates homocysteine (Hcy) to methionine by methylene tetrahydrofolate reductase-dependent pathways. Folic acid also generates high-energy phosphates, behaves as an antioxidant and improves nitric oxide (NO) production by endothelial NO synthase. Interestingly, during epigenetic modification, methylation of DNA/RNA generate homocysteine unequivocally. The enhanced overexpression of methyl transferase lead to increased yield of Hcy. The accumulation of Hcy causes vascular dysfunction, reduces perfusion in the muscles thereby causing musculopathy. Another interesting fact is that children with severe hyperhomocysteinaemia (HHcy) have skeletal deformities, and do not live past teenage. HHcy is also associated with the progeria syndrome. Epilepsy is primarily caused by inhibition of gamma-amino-butyric-acid (GABA) receptor, an inhibitory neurotransmitter in the neuronal synapse. Folate deficiency leads to HHcy which then competes with GABA for binding on the GABA receptors. With so many genetic and clinical manifestations associated with folate deficiency, we propose that folate deficiency induces epigenetic alterations in the genes and thereby results in disease. PMID:24213682

Bhargava, Seema; Tyagi, S C



Mutation at the folate receptor 4 locus modulates gene expression profiles in the mouse uterus in response to preconceptual folate supplementation  

PubMed Central

Periconceptional supplementation of folic acid to the diet of women is considered a great success for a public health intervention. Higher folate status, either by supplementation, or via the mandatory fortification of grain products in the United States, has lead to significant reduction in the incidence of neural tube defects. Besides birth defects, folate deficiency has been linked to a variety of morbidities, most notably to increased risk for cancer. However, recent evidence suggests that excess folate may be detrimental - for birth defect incidence or in the progression of cancer. How folate mediates beneficial or detrimental effects is not well understood. It is also unknown what molecular responses are elicited in women taking folate supplements, and thus experience a bolus of folate on top of the status achieved by fortification. To characterize the response to a preconceptional regimen of supplementation with folinic acid, we performed gene expression profiling experiments on uterus tissue of pregnant mice with either wildtype alleles or targeted disruption at the folate receptor 4 locus. We observed that, depending on the genetic background, folinic acid supplementation affects expression of genes that contribute to lipid metabolism, protein synthesis, mitochondrial function, cell cycle, and cell activation. The extent of the response is strongly modulated by the genetic background. Finally, we provide evidence that folinic acid supplementation in the mutant paradigm affects histone methylation status, a potential mechanisms of gene regulation in this model. PMID:23651732

Salbaum, J. michael; Kruger, Claudia; Kappen, Claudia



Chemical synthesis of deuterated folate monoglutamate and in vivo assessment of urinary excretion of deuterated folates in man  

SciTech Connect

The synthesis and in vivo application of stable-isotopically labeled folic acid was investigated to devise methods suitable for studies of folate metabolism in human subjects. Glutamate-labeled tetradeutero-pteroylglutamic acid (d4-folic acid) was prepared by mixed anhydride coupling of N10-trifluoroacetylpteroic acid and dimethyl L-(3,3,4,4-2H4)glutamic acid, saponification in sodium deuteroxide, and chromatographic purification. Retention of the isotopic label was verified by proton NMR and mass spectrometry of the para-aminobenzoylglutamic acid product of C9-N10 bond cleavage. A method was devised for determination of of isotopic enrichment of urinary d4-folates derived from orally administered d4-folic acid using affinity chromatographic purification, chemical cleavage of the C9-N10 bond, HPLC isolation of the p-(2H4)aminobenzoylglutamate product, followed by negative-ion chemical-ionization gas chromatography/mass spectrometry. Data concerning the urinary excretion of d4-folates derived from an oral dose of d4-folic acid in an adult human are presented.

Gregory, J.F. III; Toth, J.P.



A novel deletion mutation in the proton-coupled folate transporter (PCFT; SLC46A1) in a Nicaraguan child with hereditary folate malabsorption  

PubMed Central

Hereditary Folate Malabsorption (OMIM 229050) is a rare autosomal recessive disorder caused by loss-of-function mutations in the proton-coupled folate transporter gene (PCFT/SLC46A1) resulting in impaired folate transport across the intestine and into the central nervous system. We report a novel, homozygous, deletion mutation in a child of Nicaraguan descent in exon 2 (c.558-588del, ss778190447) at amino acid position I188S resulting in a frame shift with a premature stop. PMID:23816405

Diop-Bove, N; Jain, M.; Scaglia, F.; Goldman, I.D.



Estimation of serum and erythrocyte folate concentrations in the New Zealand adult population within a background of voluntary folic acid fortification.  


National data on the blood folate status of New Zealand adults is lacking. The objective of this study was to describe the blood folate status and examine the predictors of blood folate status in a national sample of adults from New Zealand, a country with voluntary folic acid fortification. The 2008/09 New Zealand Adult Nutrition Survey was a nationwide multistage systematic random cross-sectional survey. Serum and erythrocyte folate concentrations were measured by microbiologic assay. The survey included 4721 participants aged ?15 y, 3359 of whom provided a nonfasting blood sample. Biochemical folate status was measured in 3277 participants. The median serum and erythrocyte folate concentrations were 23 and 809 nmol/L, respectively. The prevalence of biochemical folate deficiency, defined as plasma folate <6.8 nmol/L or erythrocyte folate <305 nmol/L, was 2%. Having breakfast daily compared with never eating breakfast was associated with 53% higher serum and 25% higher erythrocyte folate concentrations; consumers of fortified yeast extract spread had 17% higher serum and 14% higher erythrocyte folate concentrations than nonconsumers; daily users of folate-containing supplements compared with nonusers had 48% higher serum and 28% higher erythrocyte folate concentrations. The prevalence of biochemical folate deficiency in New Zealand adults is low. Participants who ate breakfast more frequently, consumed folate-fortified yeast, or used a daily folate supplement had higher blood folate concentrations. PMID:24174623

Bradbury, Kathryn E; Williams, Sheila M; Mann, Jim I; Brown, Rachel C; Parnell, Winsome; Skeaff, C Murray



Folate intake and the MTHFR C677T genotype influence choline status in young Mexican American women  

Microsoft Academic Search

Numerous studies have reported a relationship between folate status, the methylenetetrahydrofolate reductase (MTHFR) 677C?T variant and disease risk. Although folate and choline metabolism are inter-related, only limited data are available on the relationship between choline and folate status in humans. This study sought to examine the influences of folate intake and the MTHFR 677C?T variant on choline status. Mexican-American women

Christian M. Abratte; Wei Wang; Rui Li; David J. Moriarty; Marie A. Caudill




EPA Science Inventory

Folate deficiency increases background levels of DNA damage and can enhance the genotoxicity of chemical agents. Arsenic, a known human carcinogen present in drinking water supplies around the world, induces chromosomal and DNA damage. The effect of dietary folate deficiency on...


Intracellular trafficking/membrane targeting of human reduced folate carrier expressed in Xenopus oocytes  

E-print Network

Intracellular trafficking/membrane targeting of human reduced folate carrier expressed in Xenopus Parker, and Hamid M. Said. Intracellular trafficking/ membrane targeting of human reduced folate carrier trafficking of the protein. Confocal imaging of human RFC (hRFC) fused to the enhanced green fluorescent

Marchant, Jonathan


Nutrient Intake Values for Folate during Pregnancy and Lactation Vary Widely around the World  

PubMed Central

Folate is a B-vitamin with particular importance during reproduction due to its role in the synthesis and maintenance of DNA. Folate is well known for its role in preventing neural tube defects (NTDs) during the periconceptional period. There is also an increased need for folate throughout pregnancy to support optimal growth and development of the fetus and blood volume expansion and tissue growth of the mother. During lactation, women are at risk of folate deficiency due to increased demands to accommodate milk folate levels. Nutrient Intake Values (NIVs) for folate have been calculated to take into account additional needs during pregnancy and lactation. However, these values vary widely between countries. For example, the folate requirement that is set to meet the needs of almost all healthy women during pregnancy varies from 300 µg/day in the United Kingdom to 750 µg/day in Mexico. Currently, there is no accepted standardized terminology or framework for establishing NIVs. This article reviews country-specific NIVs for folate during pregnancy and lactation and the basis for setting these reference values. PMID:24084052

Stamm, Rosemary A.; Houghton, Lisa A.



Self-illuminating nanoprobe for in vivo imaging of cancers over-expressing the folate receptor  

NASA Astrophysics Data System (ADS)

New in vivo imaging reagents with increased sensitivity and penetration depth are needed to advance our understanding of metastases and accelerate the development of therapeutics. The folate receptor (FR) is a promising imaging target that is up-regulated in many human carcinomas, including cancers of the ovary, breast, pancreas, endometrium, lungs, kidneys, colon, brain, and myeloid cells. Zymera has developed a self-illuminating Bioluminescence Resonance Energy Transfer Quantum Dot (BRET-Qdot) nanoprobe conjugated with folate (BQ-Folate) for in vivo imaging of cancers overexpressing FR. BQ-Folate is a novel nanoprobe formed by co-conjugating Renilla reniformis luciferase enzyme and folate to near-infrared (NIR) emitting quantum dots. The luciferase substrate, coelenterazine, activates the BQ-Folate nanoprobe generating luminescence emission in the near-infrared (NIR) region (655 nm) for increased sensitivity and penetration depth. Because BQ-Folate requires no external light source for light emission, it has significant advantages for challenging in vivo preclinical optical imaging applications, such as the detection of early stage metastases. Zymera and OncoMed Pharmaceuticals have demonstrated that in vivo imaging with the BQ-Folate nanoprobe detected the primary tumor and early stage metastases in an orthotopic NOD/SCID mouse model of human pancreatic cancer.

Miller, Steven C.; Beviglia, Lucia; Yeung, Pete; Bhattacharyya, Sukanta; Sobek, Daniel



Dietary folate deficiency blocks prostate cancer progression in the TRAMP model.  


Dietary folate is essential in all tissues to maintain several metabolite pools and cellular proliferation. Prostate cells, due to specific metabolic characteristics, have increased folate demand to support proliferation and prevent genetic and epigenetic damage. Although several studies have found that dietary folate interventions can affect colon cancer biology in rodent models, its impact on prostate is unknown. The purpose of this study was to determine whether dietary folate manipulation, possibly being of primary importance for prostate epithelial cell metabolism, could significantly affect prostate cancer progression. Strikingly, mild dietary folate depletion arrested prostate cancer progression in 25 of 26 transgenic adenoma of the mouse prostate (TRAMP) mice, in which tumorigenesis is prostate-specific and characteristically aggressive. The significant effect on prostate cancer growth was characterized by size, grade, proliferation, and apoptosis analyses. Folate supplementation had a mild, nonsignificant, beneficial effect on grade. In addition, characterization of folate pools (correlated with serum), metabolite pools (polyamines and nucleotides), genetic and epigenetic damage, and expression of key biosynthetic enzymes in prostate tissue revealed interesting correlations with tumor progression. These findings indicate that prostate cancer is highly sensitive to folate manipulation and suggest that antifolates, paired with current therapeutic strategies, might significantly improve treatment of prostate cancer, the most commonly diagnosed cancer in American men. PMID:21836022

Bistulfi, Gaia; Foster, Barbara A; Karasik, Ellen; Gillard, Bryan; Miecznikowski, Jeff; Dhiman, Vineet K; Smiraglia, Dominic J



Folate, vitamin B12 and postmenopausal breast cancer in a prospective study of French women.  

E-print Network

Folate, vitamin B12 and postmenopausal breast cancer in a prospective study of French women. Martin and examine whether the relation is affected by alcohol and intake of vitamin B2 and B12. Methods intake. The decreasing trend was most marked in women with higher folate and vitamin B12 intake. However

Paris-Sud XI, Université de


Genome-wide Association Study of Vitamin B6, Vitamin B12, Folate,  

E-print Network

REPORT Genome-wide Association Study of Vitamin B6, Vitamin B12, Folate, and Homocysteine Blood Schlessinger,12 Manuela Uda,6 and Luigi Ferrucci2 The B vitamins are components of one-carbon metabolism (OCM circulating vitamin B6, vitamin B12, folate and homocysteine, a genome-wide association analysis was conducted

Abecasis, Goncalo


Long-term stability of folate in dried blood spots stored in several conditions  

PubMed Central

We examined stability of folate in 50 subjects’ dried cord blood spots stored for 9 months at ?80 °C, 4 °C, ambient and humid conditions. Mean folate declined progressively, but most subjects were +/? 3 ranks of their ?80 °C position. Meaningful information about relative concentrations was retained across conditions. PMID:23623515

Zimmerman, Rheanne K.; Slater, Megan E.; Langer, Erica K.; Ross, Julie A.; Spector, Logan G.



Folate receptor targeted Type 1 photosensitizer bioconjugates for tumor visualization and phototherapy  

NASA Astrophysics Data System (ADS)

Folate receptors are over expressed in many types of cancers, including, ovarian, breast, and cervical. In our continuing efforts toward the development of targeted Type 1 phototherapeutic agents, an azide-based Type 1 photosensitizer and a pyrzine-based fluorophore that absorb and emits in the visible region, and a dual diagnostic-therapeutic probe consisting of the fluorophore and the photosensitizer were prepared and independently conjugated to two folate receptor specific vectors: ?-carboxyl-modified folic acid and anti-human FOLR1 (folate receptor-1) antibody In vitro receptor binding study showed that all the conjugates had high (ca 1-7 nM) affinity to the folate receptor. Confocal microscopy images indicated that the pyrazine conjugates were selectively taken up by the folate receptor expressing ovarian cancer KB cells.

Rajagopalan, Raghavan; Poreddy, Amruta R.; Karwa, Amolkumar; Asmelash, Bethel; Putnam, Nicole E.; Chinen, Lori; Nichols, Maureen; Shieh, J. Jeng; Dorshow, Richard B.



Folate Receptor Alpha Expression in Lung Cancer: Diagnostic and Prognostic Significance  

PubMed Central

With the advent of targeted therapies directed towards folate receptor alpha, with several such agents in late stage clinical development, the sensitive and robust detection of folate receptor alpha in tissues is of importance relative to patient selection and perhaps prognosis and prediction of response. The goal of the present study was to evaluate the expression of folate receptor alpha in non-small cell lung cancer specimens to determine its frequency of expression and its potential for prognosis. The distribution of folate receptor alpha expression in normal tissues as well as its expression and relationship to non-small cell lung cancer subtypes was assessed by immunohistochemistry using tissue microarrays and fine needle aspirates and an optimized manual staining method using the recently developed monoclonal antibody 26B3. The association between folate receptor alpha expression and clinical outcome was also evaluated on a tissue microarray created from formalin fixed paraffin embedded specimens from patients with surgically resected lung adenocarcinoma. Folate receptor alpha expression was shown to have a high discriminatory capacity for lung adenocarcinomas versus squamous cell carcinomas. While 74% of adenocarcinomas were positive for folate receptor alpha expression, our results found that only 13% of squamous cell carcinomas were FRA positive (p<0.0001). In patients with adenocarcinoma that underwent surgical resection, increased folate receptor alpha expression was associated with improved overall survival (Hazard Ratio 0.39, 95% CI 0.18-0.85). These data demonstrate the diagnostic relevance of folate receptor alpha expression in non-small cell lung cancer as determined by immunohistochemistry and suggest that determination of folate receptor alpha expression provides prognostic information in patients with lung adenocarcinoma. PMID:22547449

O'Shannessy, Daniel J.; Yu, Gordon; Smale, Robert; Fu, Yao-Shi; Singhal, Sunil; Thiel, Robert P.; Somers, Elizabeth B.; Vachani, Anil



The effect of ethanol on the urinary excretion and differential metabolism of folate compounds  

SciTech Connect

In rats chronically fed ethanol and folate-containing diets for 12 weeks, urinary folate excretion was increased. However, no significant tissue depletion was noted unless rats were fed folate deficient diets. In rats fed folate-deficient diets urinary folate excretion was dramatically decreased at two weeks, when tissue folate stores were replete. After 16 weeks of diet treatment, the urinary excretion of an intraperitoneal dose of {sup 3}H-PteGlu was not altered in folate-deficient rats. Although acute ethanol administration (oral or intravenous) increased endogenous folate excretion that of {sup 3}H-PteGlu was not significantly altered, nor was the fractional excretion of {sup 3}H-label. To clarify this effect, the metabolism of {sup 3}H-PteGlu was studied. HPLC analysis of urine showed extensive metabolism of {sup 3}H-PteGlu to other folate substrates. Oral ethanol-treatment increased the fractional excretion of endogenous 5-CH{sub 3}-H{sub 4}PteGlu with no increase in urinary excretion or fractional excretion of other {sup 3}H-labeled derivatives. After infusion of tritium labeled 5-CH{sub 3}-H{sub 4}PteGlu, ethanol treatment increased the fractional excretion of endogenous and {sup 3}H-5-CH{sub 3}-H{sub 4}PteGlu, but not that of other folates. There was rapid uptake of {sup 3}H-label by the kidney with only 10% of the urinary {sup 3}H-label as {sup 3}H-5-CH{sub 3}-H{sub 4}PteGlu.

Eisenga, B.H.



Low colonocyte folate is associated with uracil misincorporation and global DNA hypomethylation in human colorectum.  


Low folate status is a risk factor for colon carcinogenesis; mechanisms proposed to account for this relationship include uracil misincorporation into DNA and global DNA hypomethylation. We investigated whether such biomarkers are related to folate status in isolated colonocytes from colonoscopy patients. In cases with adenomatous polyps (n = 40) or hyperplastic polyps (n = 16), colonocytes were isolated from biopsies from the polyp, from a site adjacent to the polyp, and from normal mucosa 10-15 cm distal to the polyp. In polyp-free controls (n = 53), biopsies were taken from ascending, transverse, and descending areas of colon. Within adenoma cases, there was a trend (P-trend < 0.001) of decreasing colonocyte folate (pg/10? cells, mean ± CI) from the site distal to the polyp (16.9 ± 2.4), to the site adjacent to the polyp (14.7 ± 2.3), to the polyp (12.8 ± 2.0). Correspondingly, there were increases in uracil misincorporation (P-trend < 0.001) and global DNA hypomethylation (P-trend = 0.012) across the 3 sites. Colonocyte folate concentrations were significantly correlated with RBC folate concentrations, but only in individuals with generally lower (?484 ?g/L) RBC folate status (r = 0.54; P = 0.006; n = 24), and were also significantly lower in normal mucosa of cases with adenomatous polyps than in controls matched for colonic segment. In conclusion, localized folate deficiency in specific areas of colon might create carcinogenic fields and affect the development of colorectal polyps through uracil misincorporation and DNA hypomethylation; alternatively, the polyp itself might deplete folate in the surrounding tissue. Folate supplementation trials aimed at colon cancer prevention should target individuals with suboptimal folate status. PMID:23190761

McGlynn, Angela P; Wasson, Gillian R; O'Reilly, Sharleen L; McNulty, Helene; Downes, C Stephen; Chang, Chin-Kuo; Hoey, Leane; Molloy, Anne M; Ward, Mary; Strain, J J; McKerr, George; Weir, Donald G; Scott, John M



Metabolism of the Folate Precursor p-Aminobenzoate in Plants  

PubMed Central

Plants produce p-aminobenzoate (pABA) in chloroplasts and use it for folate synthesis in mitochondria. In plant tissues, however, pABA is known to occur predominantly as its glucose ester (pABA-Glc), and the role of this metabolite in folate synthesis has not been defined. In this study, the UDP-glucose:pABA acyl-glucosyltransferase (pAGT) activity in Arabidopsis extracts was found to reside principally (95%) in one isoform with an apparent Km for pABA of 0.12 mm. Screening of recombinant Arabidopsis UDP-glycosyltransferases identified only three that recognized pABA. One of these (UGT75B1) exhibited a far higher kcat/Km value than the others and a far lower apparent Km for pABA (0.12 mm), suggesting its identity with the principal enzyme in vivo. Supporting this possibility, ablation of UGT75B1 reduced extractable pAGT activity by 95%, in vivo [14C]pABA glucosylation by 77%, and the endogenous pABA-Glc/pABA ratio by 9-fold. The Keq for the pABA esterification reaction was found to be 3 × 10-3. Taken with literature data on the cytosolic location of pAGT activity and on cytosolic UDP-glucose/UDP ratios, this Keq value allowed estimation that only 4% of cytosolic pABA is esterified. That pABA-Glc predominates in planta therefore implies that it is sequestered away from the cytosol and, consistent with this possibility, vacuoles isolated from [14C]pABA-fed pea leaves were estimated to contain?88% of the [14C]pABA-Glc formed. In total, these data and the fact that isolated mitochondria did not take up [3H]pABA-Glc, suggest that the glucose ester represents a storage form of pABA that does not contribute directly to folate synthesis. PMID:18385129

Eudes, Aymerick; Bozzo, Gale G.; Waller, Jeffrey C.; Naponelli, Valeria; Lim, Eng-Kiat; Bowles, Dianna J.; Gregory, Jesse F.; Hanson, Andrew D.



Folate-binding Protein Is a Marker for Ovarian Cancer  

Microsoft Academic Search

ABSTRACT We describe the isolation of a complementary,DNA (cDNA) sequence encoding,the ovarian cancer-associated,antigen recognized by monoclonal antibody,MOvl8 and its identification as a high-affinity folate-binding protein (FBP). Functional cDNA clones were isolated using niKN A from the ovarian carcinoma,cell line SKOV3 and,colon carcinoma,cell line HT29, by transient expression in WOP cells and selection of expressing cells by adhesion,to antibody-coated magnetic,beads. The

Ian G. Campbell; Tania A. Jones; William D. Foulkes; John Trowsdale



Comparison of (6 S)-5-methyltetrahydrofolic acid v. folic acid as the reference folate in longer-term human dietary intervention studies assessing the relative bioavailability of natural food folates: comparative changes in folate status following a 16-week placebo-controlled study in healthy adults.  


Folic acid (pteroylmonoglutamic acid) has historically been used as the reference folate in human intervention studies assessing the relative bioavailability of dietary folate. Recent studies using labelled folates indicated different plasma response kinetics to folic acid than to natural (food) folates, thus obviously precluding its use in single-dose experiments. Since differences in tissue distribution and site of biotransformation were hypothesised, the question is whether folic acid remains suitable as a reference folate for longer-term intervention studies, where the relative bioavailability of natural (food) folate is assessed based on changes in folate status. Healthy adults aged 18-65 years (n 163) completed a 16-week placebo-controlled intervention study in which the relative bioavailability of increased folate intake (453 nmol/d) from folate-rich foods was assessed by comparing changes in plasma and erythrocyte folate concentration with changes induced by an equal reference dose of supplemental (6S)-5-methyltetrahydrofolic acid or folic acid. The relative increase in plasma folate concentration in the food group was 31 % when compared with that induced by folic acid, but 39 % when compared with (6S)-5-methyltetrahydrofolic acid. The relative increase in erythrocyte folate concentration in the food group when compared with that induced by folic acid was 43 %, and 40 % when compared with (6S)-5-methyltetrahydrofolic acid. When recent published observations were additionally taken into account it was concluded that, in principle, folic acid should not be used as the reference folate when attempting to estimate relative natural (food) folate bioavailability in longer-term human intervention studies. Using (6S)-5-methyltetrahydrofolic acid as the reference folate would avoid future results' validity being questioned. PMID:19852872

Wright, Anthony J A; King, Maria J; Wolfe, Caroline A; Powers, Hilary J; Finglas, Paul M



Water soluble folate-chitosan nanogels crosslinked by genipin.  


Folate-chitosan conjugates were prepared by a concurrent functionalization and crosslinking reaction with the natural crosslinker genipin. Genipin molecule was employed simultaneously as crosslinker agent and spacer molecule in order to allow the functionalization with folic acid for active tumor targeting. The reaction was carried out in reverse microemulsion which provided colloidal size and monodisperse particle size distribution. The water solubility of the obtained folate-genipin-chitosan nanogels was studied as function of the pH of the medium and all nanoparticles were totally dispersible at physiological pH. The enzymatic degradability of the nanogels in a lysozyme solution was evaluated at acidic and physiological pH. QELS analyses of the swelling behavior of the nanogels with the pH did not show a clear pH-sensitivity. However, the study on the loading and release capacity of 5-fluorouracil revealed an interesting pH-responsive behavior of the nanogels that makes them promising as nanodevices for targeted anticancer drug delivery. PMID:24299756

Pujana, Maite Arteche; Pérez-Álvarez, Leyre; Iturbe, L Carlos Cesteros; Katime, Issa



Folate and vitamin B-12 biomarkers in NHANES: history of their measurement and use12345  

PubMed Central

NHANES measured folate and vitamin B-12 status biomarkers, starting with serum folate from NHANES I (1974–1975) through 2010. Subsequent NHANES measured additional biomarkers [eg, red blood cell folate, serum vitamin B-12, total homocysteine (tHcy), methylmalonic acid, serum folic acid, and 5-methyltetrahydrofolic acid]. Examples of the uses of these data are wide ranging and include public policy applications, the derivation of reference intervals, and research. Periodically, the National Center for Health Statistics and its federal partners convene expert panels to review the use of the folate- and vitamin B-12–related biomarkers in NHANES. These panels have evaluated the need for results to be comparable across time and with published data and the use of crossover studies and adjustment equations to ensure comparability. With the recent availability of reference methods and materials for serum folate and tHcy, NHANES has started to use traceability approaches to enhance the accuracy and comparability of its results. A major user concern over the years has been the use of cutoffs to estimate the prevalence of inadequate folate and vitamin B-12 status. Because these cutoffs depend on the measurement procedure, several expert panels suggested approaches for dealing with cutoff challenges. This review summarizes the history and use of folate- and vitamin B-12–related biomarkers beginning with NHANES I (1974–1975) through 2010. PMID:21593508

Johnson, Clifford L



How folate metabolism affects colorectal cancer development and treatment; a story of heterogeneity and pleiotropy.  


Folate was identified as an essential micronutrient early in the twentieth century and anti-folate chemotherapy such as 5-fluorouracil (5-FU) has been central to the medical management of solid tumours including colorectal cancer for more than five decades. In the intervening years, evidence has been gathered which shows that folate deficiency leads to many human diseases throughout the life-course. However, we still do not know all of the mechanisms behind functional folate deficiency, or indeed its rescue through supplementation with natural and particularly synthetic folates. There is growing evidence that one adverse effect of folic acid fortification programmes is an increased risk of colorectal cancer within populations. The complexity of folate-dependent, one-carbon metabolism and the heterogeneity that exists between individuals with respect to the enzymes involved in the anabolic pathways, and the catabolism of 5-FU, are explored in this review. The enzyme products of some genes such as MTHFR exert multiple and perhaps unrelated effects on many phenotypes, including cancer development. We describe this pleiotropy and the common genetic variants that affect folate metabolism; and discuss some of the studies that have investigated their potential as predictive biomarkers. PMID:24614284

Jennings, Barbara Anne; Willis, Gavin



Folate regulation of axonal regeneration in the rodent central nervous system through DNA methylation  

PubMed Central

The folate pathway plays a crucial role in the regeneration and repair of the adult CNS after injury. Here, we have shown in rodents that such repair occurs at least in part through DNA methylation. In animals with combined spinal cord and sciatic nerve injury, folate-mediated CNS axon regeneration was found to depend on injury-related induction of the high-affinity folate receptor 1 (Folr1). The activity of folate was dependent on its activation by the enzyme dihydrofolate reductase (Dhfr) and a functional methylation cycle. The effect of folate on the regeneration of afferent spinal neurons was biphasic and dose dependent and correlated closely over its dose range with global and gene-specific DNA methylation and with expression of both the folate receptor Folr1 and the de novo DNA methyltransferases. These data implicate an epigenetic mechanism in CNS repair. Folic acid and possibly other nontoxic dietary methyl donors may therefore be useful in clinical interventions to promote brain and spinal cord healing. If indeed the benefit of folate is mediated by epigenetic mechanisms that promote endogenous axonal regeneration, this provides possible avenues for new pharmacologic approaches to treating CNS injuries. PMID:20424322

Iskandar, Bermans J.; Rizk, Elias; Meier, Brenton; Hariharan, Nithya; Bottiglieri, Teodoro; Finnell, Richard H.; Jarrard, David F.; Banerjee, Ruma V.; Skene, J.H. Pate; Nelson, Aaron; Patel, Nirav; Gherasim, Carmen; Simon, Kathleen; Cook, Thomas D.; Hogan, Kirk J.



Folate-Equipped Nanolipoplexes Mediated Efficient Gene Transfer into Human Epithelial Cells  

PubMed Central

Since recombinant viral vectors have been associated with serious side effects, such as immunogenicity and oncogenicity, synthetic delivery systems represent a realistic alternative for achieving efficacy in gene therapy. A major challenge for non-viral nanocarriers is the optimization of transgene expression in the targeted cells. This goal can be achieved by fine-tuning the chemical carriers and the adding specific motifs to promote cellular penetration. Our study focuses on the development of novel folate-based complexes that contain varying quantities of folate motifs. After controlling for their physical properties, neutral folate-modified lipid formulations were compared in vitro to lipoplexes leading to comparable expression levels. In addition, no cytotoxicity was detected, unlike what was observed in the cationic controls. Mechanistically, the delivery of the transgene appeared to be, in part, due to endocytosis mediated by folate receptor targeting. This mechanism was further validated by the observation that adding free folate into the medium decreased luciferase expression by 50%. In vivo transfection with the folate-modified MM18 lipid, containing the highest amount of FA-PEG570-diether co-lipid (w:w; 90:10), at a neutral charge ratio, gave luciferase transgene expression. These studies indicate that modification of lipids with folate residues could enhance non-toxic, cell-specific gene delivery. PMID:23344053

Mornet, Emmanuel; Carmoy, Nathalie; Lainé, Céline; Lemiègre, Loïc; Le Gall, Tony; Laurent, Isabelle; Marianowski, Remi; Férec, Claude; Lehn, Pierre; Benvegnu, Thierry; Montier, Tristan



Serum folate levels after UVA exposure: a two-group parallel randomised controlled trial  

PubMed Central

Background Photodegradation of certain vitamins such as riboflavins, carotinoids, tocopherol, and folate has been well-documented. Previous observations suggest that ultraviolet (UV) radiation may cause folate deficiency. This is of great importance since folate deficiency is also known to be linked with the development of neural tube defects. To investigate the influence of UVA radiation on serum folate levels in vivo, we conducted a two-group randomised controlled trial on healthy subjects. Material and methods Twenty-four healthy volunteers with skin type II were enrolled into the study. Eight volunteers of the study population were randomly assigned to the control group. UVA irradiation was administered with an air-conditioned sunbed. Blood samples were taken from all volunteers at baseline (T1), 30 min after the first UVA exposure (T2), and at the end of the study 24 h after the sixth UV exposure (T3). The volunteers had two UVA exposures weekly within three weeks (cumulative UVA dose: 96 J/cm2). Volunteers of the control group had no UVA exposures. Serum folate was analysed with an automated immunoassay system. Results At all times of blood collection the differences between serum folate levels were insignificant (P > 0.05), except of the non-exposed controls at T2 (P < 0.05). We did not observed significant differences of folate levels between UVA exposed and non-exposed volunteers (P > 0.05). Conclusions Our data suggest that both single and serial UVA exposures do not significantly influence serum folate levels of healthy subjects. Therefore, neural tube defects claimed to occur after periconceptual UVA exposure are probably not due to UVA induced folate deficiency. PMID:11737876

Gambichler, Thilo; Bader, Armin; Sauermann, Kirsten; Altmeyer, Peter; Hoffmann, Klaus



Folate and vitamin B12 status of women in Newfoundland at their first prenatal visit  

PubMed Central

BACKGROUND: Newfoundland has one of the highest rates of neural tube defects in North America. Given the association between low maternal folic acid levels and neural tube defects, a cross-sectional study was conducted to obtain base-line data on the folate and vitamin B12 status of a sample of women in Newfoundland who were pregnant. METHODS: Blood samples were collected between August 1996 and July 1997 from 1424 pregnant women in Newfoundland during the first prenatal visit (at approximately 16 weeks' gestation); this represented approximately 25% of the women in Newfoundland who were pregnant during this period. The samples were analysed for serum folate, vitamin B12, red blood cell folate and homocysteine. RESULTS: Median values for serum folate, red blood cell folate and serum vitamin B12 were 25 nmol/L, 650 nmol/L and 180 pmol/L, respectively. On the basis of the interpretive criteria used for red blood cell folate status, 157 (11.0%) of the 1424 women were deficient (< 340 nmol/L) and a further 180 (12.6%) were classified as indeterminate (340-420 nmol/L). Serum homocysteine levels, measured in subsets of the red blood cell folate status groups, supported the inadequate folate status. Serum vitamin B12 levels of 621 (43.6%) women were classified as deficient or marginal; however, the validity of the interpretive criteria for pregnant women is questionable. INTERPRETATION: A large proportion of pregnant women surveyed in Newfoundland in 1997 had low red blood cell folate levels. PMID:10862228

House, J D; March, S B; Ratnam, S; Ives, E; Brosnan, J T; Friel, J K



Health promotion in a primary health care setting. Neural tube defects and folate.  


Primary care practitioners are ideally situated to carry out health promotion activities. Neural tube defects are of a fairly low incidence, but the consequences are tragic. They range from life long physical and often intellectual disabilities, to death at birth. Increased folate intake, either through eating folate rich foods or through supplementation, has been shown to reduce the incidence of neural tube defects in newborns by up to 75%. Encouraging all women of child-bearing age to increase their folate intake could thus prevent a significant number of neural tube defects occurring in the Australian population. PMID:17987155

French, S D



Synthesis and activity of folate conjugated didemnin B for potential treatment of inflammatory diseases.  


A folate receptor targeted didemnin B conjugate was synthesized using a hydrophilic peptide spacer linked to folate via a releasable disulfide carbonate linker. Cell cytotoxicity and TNF-? inhibition in RAW264.7 macrophage-like cells exhibited IC(50)s of 13 and 5 nM, respectively. Folate didemnin B was found to be ?50-100 fold more potent than didemnin B itself. More importantly, activity of the prodrug was blocked by excess folic acid, demonstrating receptor-mediated cellular uptake of the conjugate. PMID:22100311

Henne, Walter A; Kularatne, Sumith A; Ayala-López, Wilfredo; Doorneweerd, Derek D; Stinnette, Torian W; Lu, Yingjuan; Low, Philip S



Psychotic disorder and extrapyramidal symptoms associated with vitamin B12 and folate deficiency.  


Vitamin B12 and folate deficiency causing neuropsychiatric and thrombotic manifestations, such as peripheral neuropathy, subacute combined degeneration of cord, dementia, ataxia, optic atrophy, catatonia, psychosis, mood disturbances, myocardial infarction and portal vein thrombosis are well known. This present report highlights an unusual presentation of vitamin B12 deficiency-psychotic disorder, extrapyramidal symptoms in a 12-year-old boy. His symptoms responded to parenteral vitamin B12 therapy. So with this report we emphasized that serum vitamin B12 and folate levels should be measured, especially in those patients who present with other known neuropsychiatric features of vitamin B12 and folate deficiency. PMID:19095695

Dogan, Murat; Ozdemir, Osman; Sal, Ertan A; Dogan, S Zehra; Ozdemir, Pinar; Cesur, Yasar; Caksen, Hüseyin



Imaging sites of infection using a 99mTc-labeled folate conjugate targeted to folate receptor positive macrophages.  


EC20, a folate-targeted (99m)Tc based radioimaging agent with a high folate receptor (FR) binding affinity, has been used for both the diagnosis and the staging of FR positive malignancies (currently in phase III trials) and also for the localization of inflamed lesions characterized by the accumulation of FR+ macrophages. Because recent evidence has suggested that FR+ macrophages might accumulate at sites of infectious disease, this study evaluated whether EC20 might prove similarly useful for imaging bacterial infection foci. Using gamma scintigraphic imaging, it was demonstrated that EC20 accumulated at sites of Staphylococcus aureus infection with a significant difference (P < 0.0001, n = 12) in enrichment noted between infected and noninfected limbs. Confirmation that the elevated uptake of EC20 in infected limbs was FR-mediated was supported by suppression of EC20 accumulation in the presence of a 200-fold excess of free folic acid (P < 0.0001, n = 12). This study establishes for the first time the use of EC20 to image and localize sites of infectious disease. PMID:22468849

Henne, Walter A; Rothenbuhler, Ryan; Ayala-Lopez, Wilfredo; Xia, Wei; Varghese, Bindu; Low, Philip S




EPA Science Inventory

The similarity of stress ethylene biosynthesis in whole plants to endogenous ethylene biosynthesis was investigated using two inhibitors of ethylene biosynthesis, amino-ethoxyvinylglycine (AVG) and cobalt chloride (Co2+); and the intermediates, methionine, S-adenosylmethionine (S...


Identification of novel mutations in the proton-coupled folate transporter (PCFT-SLC46A1) associated with hereditary folate malabsorption  

PubMed Central

Hereditary folate malabsorption (HFM) is an autosomal recessive disorder, recently shown to be due to loss-of-function mutations of the proton-coupled folate transporter (PCFT-SLC46A1), resulting in systemic and central nervous system folate deficiency. Data is emerging on the spectrum of PCFT mutations associated with this disorder. In this report, novel mutations are described in three subjects with HFM: A335D/N68Kfs (c.1004C>A/ c.204-205delCC), a compound heterozygous mutation, and two homozygous PCFT mutations, G338R (c.1012G>C) and E9Gfs (c.17-18insC). Functional assessment of A335D and G338R PCFT mutants transfected into folate transporter-deficient HeLa R1-11 cells indicated a complete loss of transport activity. There were neurological deficiencies in two of the families reported; in particular, late-onset seizures. The importance of early diagnosis and treatment to achieve physiological cerebrospinal fluid folate levels is emphasized. PMID:21333572

Shin, Daniel Sanghoon; Mahadeo, Kris; Min, Sang Hee; Diop-Bove, Ndeye; Clayton, Peter; Zhao, Rongbao; Goldman, I. David



The spectrum of mutations in the PCFT gene, coding for an intestinal folate transporter, that are the basis for hereditary folate malabsorption  

PubMed Central

Hereditary folate malabsorption (HFM) is a rare autosomal recessive disorder caused by impaired intestinal folate absorption and impaired folate transport into the central nervous system. Recent studies in 1 family revealed that the molecular basis for this disorder is a loss-of-function mutation in the PCFT gene encoding a proton-coupled folate transporter. The current study broadens the understanding of the spectrum of alterations in the PCFT gene associated with HFM in 5 additional patients. There was no racial, ethnic, or sex pattern. A total of 4 different homozygous mutations were detected in 4 patients; 2 heterozygous mutations were identified in the fifth patient. Mutations involved 4 of the 5 exons, all at highly conserved amino acid residues. A total of 4 of the mutated transporters resulted in a complete loss of transport function, primarily due to decreased protein stability and/or defects in membrane trafficking, while 2 of the mutated carriers manifested residual function. Folate transport at low pH was markedly impaired in transformed lymphocytes from 2 patients. These findings further substantiate the role that mutations in PCFT play in the pathogenesis of HFM and will make possible rapid diagnosis and treatment of this disorder in infants, and prenatal diagnosis in families that carry a mutated gene. PMID:17446347

Zhao, Rongbao; Min, Sang Hee; Qiu, Andong; Sakaris, Antoinette; Goldberg, Gary L.; Sandoval, Claudio; Malatack, J. Jeffrey; Rosenblatt, David S.



Isolation, sequencing, and the genomic organization of the reduced folate carrier gene in the murine system  

E-print Network

ethnic groups having higher or lower prevalence rates. Several investigators have shown a marked decrease in the occurrence and recurrence rates of NTDs with the administration of periconceptional supplemental folic acid. Intracellular folates...

Greer, Kimberly Ann



Mechanistic insights into folate supplementation from Crooked tail and other NTD-prone mutant mice  

PubMed Central

Despite two decades of research since R. Smithells and colleagues began exploring its benefits, the mechanisms through which folic acid supplementation supports neural tube closure and early embryonic development are still unclear. The greatest progress toward a molecular genetic understanding of folate effects on neural tube defect (NTD) pathogenesis has come from animal models. The numbers of NTD-associated mouse mutants accumulated and studied over the past decade have illuminated the complexity of both genetic factors contributing to NTDs and also NTD-gene interactions with folate metabolism. This article discusses insights gained from mouse models into how folate supplementation impacts neurulation. A case is made for renewed efforts to systematically screen the folate responsiveness of the scores of NTD-associated mouse mutations now identified. Designed after Crooked tail, supplementation studies of additional mouse mutants could build the molecular network maps that will ultimately enable tailoring of therapeutic regimens to individual families. PMID:19067399

Gray, Jason D.; Ross, M. Elizabeth



Low paternal dietary folate alters the mouse sperm epigenome and is associated with negative pregnancy outcomes  

PubMed Central

Epidemiological studies suggest that a father’s diet can influence offspring health. A proposed mechanism for paternal transmission of environmental information is via the sperm epigenome. The epigenome includes heritable information such as DNA methylation. We hypothesize that the dietary supply of methyl donors will alter epigenetic reprogramming in sperm. Here we feed male mice either a folate-deficient or folate-sufficient diet throughout life. Paternal folate deficiency is associated with increased birth defects in the offspring, which include craniofacial and musculoskeletal malformations. Genome-wide DNA methylation analysis and the subsequent functional analysis identify differential methylation in sperm of genes implicated in development, chronic diseases such as cancer, diabetes, autism and schizophrenia. While >300 genes are differentially expressed in offspring placenta, only two correspond to genes with differential methylation in sperm. This model suggests epigenetic transmission may involve sperm histone H3 methylation or DNA methylation and that adequate paternal dietary folate is essential for offspring health. PMID:24326934

Lambrot, R.; Xu, C.; Saint-Phar, S.; Chountalos, G.; Cohen, T.; Paquet, M.; Suderman, M.; Hallett, M.; Kimmins, S.



21 CFR 101.79 - Health claims: Folate and neural tube defects.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Health claims: Folate and neural tube defects...AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD...FOOD LABELING Specific Requirements for Health Claims § 101.79 Health...



Stereoselectivity in Polyphenol Biosynthesis  

NASA Technical Reports Server (NTRS)

Stereoselectivity plays an important role in the late stages of phenyl-propanoid metabolism, affording lignins, lignans, and neolignans. Stereoselectivity is manifested during monolignol (glucoside) synthesis, e.g., where the geometry (E or Z) of the pendant double bond affects the specificity of UDPG:coniferyl alcohol glucosyltransferases in different species. Such findings are viewed to have important ramifications in monolignol transport and storage processes, with roles for both E- and Z-monolignols and their glucosides in lignin/lignan biosynthesis being envisaged. Stereoselectivity is also of great importance in enantiose-lective enzymatic processes affording optically active lignans. Thus, cell-free extracts from Forsythia species were demonstrated to synthesize the enantiomerically pure lignans, (-)-secoisolariciresinol, and (-)-pinoresinol, when NAD(P)H, H2O2 and E-coniferyl alcohol were added. Progress toward elucidating the enzymatic steps involved in such highly stereoselective processes is discussed. Also described are preliminary studies aimed at developing methodologies to determine the subcellular location of late-stage phenylpropanoid metabolites (e.g., coniferyl alcohol) and key enzymes thereof, in intact tissue or cells. This knowledge is essential if questions regarding lignin and lignan tissue specificity and regulation of these processes are to be deciphered.

Lewis, Norman G.; Davin, Laurence B.



Biosynthesis of Dolichyl Phosphate  

PubMed Central

This is the first report not only on the presence of polyprenyl phosphates and their site of synthesis in algae, but also on the formation of their sugar derivatives in this system. A glucose acceptor lipid was isolated from the nonphotosynthetic alga Prototheca zopfii. The lipid was acidic and resistant to mild acid and alkaline treatments. The glucosylated lipid was labile to mild acid hydrolysis and resistant to phenol treatment and catalytic hydrogenation, as dolichyl phosphate glucose is. These results are consistent with the properties of an ?-saturated polyprenyl phosphate. The polyprenylic nature of the lipid was confirmed by biosynthesis from radioactive mevalonate. The [14C]lipid had the same chromatographic properties as dolichyl phosphate in DEAE-cellulose and Sephadex LH-20. Strong alkaline treatment and enzymic hydrolysis liberated free alcohols with chain lengths ranging from C90 to C105, C95 and C100 being the most abundant molecular forms. The glucose acceptor activity of the biosynthesized polyprenyl phosphate was confirmed. The ability of different subcellular fractions to synthesize dolichyl phosphate was studied. Mitochondria and the Golgi apparatus were the sites of dolichyl phosphate synthesis from mevalonate. PMID:16660269

Hopp, H. Esteban; Daleo, Gustavo R.; Romero, Pedro A.; Lezica, Rafael Pont



Folate analogues as substrates of mammalian folylpolyglutamate synthetase.  


The antifolate drugs methotrexate (MTX) and aminopterin (AM) have been tested as substrates for folylpolyglutamate synthetase (FPGS) partially purified from beef liver. The Km for MTX is 100 microM, and that for AM is 25 microM. These values are considerably higher than those for either tetrahydrofolate or folinic acid. Based on their ratios of Vmax to Km, AM is a better substrate than is MTX for the beef liver FPGS. Both are poorer substrates than tetrahydrofolate. The 7-hydroxy metabolites of MTX and AM also are substrates for FPGS. The reactivity of 7-hydroxymethotrexate is similar to that of MTX, but 7-hydroxyaminopterin is a poorer substrate than AM. Folinic acid, often used as the rescue agent in high-dose MTX therapy, has a low Km with mammalian FPGS (7 microM). Its activity is comparable to that of the best substrate, tetrahydrofolate. Low concentrations of folinic acid prevent the formation of polyglutamates of MTX. This inhibition is competitive, presumably because folinic acid and MTX are competing substrates for FPGS. The activities of folate and antifolate substrates also have been determined with rat liver FPGS. With near-saturating concentrations of AM, MTX, or 7-hydroxymethotrexate, the reaction velocity exceeds that with an optimal concentration of tetrahydrofolate. However, the Km values of the folate analogues all are greater than those of the tetrahydrofolate coenzymes. In contrast to the formation of long-chain polyglutamates observed when tetrahydrofolate or folinic acid was the substrate, beef liver FPGS, under our reaction conditions, cannot catalyze the formation from MTX monoglutamate of polyglutamates longer than the triglutamate. MTX di- and triglutamates are poorer substrates than is MTX itself. Longer polyglutamates of MTX, while having no activity as substrates, must bind to the enzyme, because they are inhibitors. Our observations using MTX and AM with the enzymatic FPGS system help to rationalize the therapeutic use of antifolates. PMID:3873989

Schoo, M M; Pristupa, Z B; Vickers, P J; Scrimgeour, K G



Biology of the Major Facilitative Folate Transporters SLC19A1 and SLC46A1  

PubMed Central

This chapter focuses on the biology of the major facilitative membrane folate transporters, the reduced folate carrier (RFC), and the proton-coupled folate transporter (PCFT). Folates are essential vitamins, and folate deficiency contributes to a variety of heath disorders. RFC is ubiquitously expressed and is the major folate transporter in mammalian cells and tissues. PCFT mediates intestinal absorption of dietary folates. Clinically relevant antifolates such as methotrexate (MTX) are transported by RFC, and the loss of RFC transport is an important mechanism of MTX resistance. PCFT is abundantly expressed in human tumors and is active under pH conditions associated with the tumor microenvironment. Pemetrexed (PMX) is an excellent substrate for PCFT as well as for RFC. Novel tumor-targeted antifolates related to PMX with selective membrane transport by PCFT over RFC are being developed. The molecular picture of RFC and PCFT continues to evolve relating to membrane topology, N-glycosylation, energetics, and identification of structurally and functionally important domains and amino acids. The molecular bases for MTX resistance associated with loss of RFC function, and for the rare autosomal recessive condition, hereditary folate malabsorption (HFM), attributable to mutant PCFT, have been established. From structural homologies to the bacterial transporters GlpT and LacY, homology models were developed for RFC and PCFT, enabling new mechanistic insights and experimentally testable hypotheses. RFC and PCFT exist as homo-oligomers, and evidence suggests that homo-oligomerization of RFC and PCFT monomeric proteins may be important for intracellular trafficking and/or transport function. Better understanding of the structure and function of RFC and PCFT should facilitate the rational development of new therapeutic strategies for cancer as well as for HFM. PMID:24745983

Hou, Zhanjun; Matherly, Larry H.



Folate Intake by Women of Child-Bearing Age: The Impact of Fortification  

E-print Network

In 1994-95, 50 to 75 percent of men and 75 to 90 percent of women, depending on age, had usual intakes of folate below their folate requirement (Institute of Medicine, 1998). In 1998, folate fortification of enriched breads, breakfast cereals, pasta, rice, and flour became mandatory. This policy was established by the Food and Drug Administration to increase folate intake among women of child-bearing age and thereby to reduce the incidence of neural tube defects in newborns. One of the key recommendations of the Dietary Guidelines for Americans 2005 applies to women of child-bearing age who may become pregnant and those in the first trimester of pregnancy: “Consume adequate synthetic folic acid daily (from fortified foods or supplements) in addition to food forms of folate from a varied diet. ” Good sources of the food forms, or naturally occurring forms, of folate include darkgreen vegetables, such as broccoli, romaine lettuce, spinach, and other dark leafy greens; dried peas and beans, such as those used in baked beans and black-eyed peas; citrus fruits and juices; peanuts; and liver. The purposes of this research were to determine (1) the proportions of low- and higher income women of child-bearing age having folate intakes below their requirements and (2) if low-income women, compared with higher income women, get a greater proportion of their total folate intake from synthetic folic acid, which is used in fortified foods. We were interested in learning whether or not the fortification policy benefits low-income women more than it does higher income women.

United States



Hearing impairment risk and interaction of folate metabolism related gene polymorphisms in an aging study  

Microsoft Academic Search

Background  Recent investigations demonstrated many genetic contributions to the development of human age-related hearing impairment (ARHI),\\u000a however, reports of factors associated with a reduction in the ARHI risk are rare. Folate metabolism is essential for cellular\\u000a functioning. Despite the extensive investigations regarding the roles of folate metabolism related gene polymorphisms in the\\u000a pathophysiology of complex diseases, such as cancer, cardio-cerebrovascular disease,

Yasue Uchida; Saiko Sugiura; Fujiko Ando; Tsutomu Nakashima; Hiroshi Shimokata



Microsatellite instability in non-neoplastic mucosa of patients with ulcerative colitis: effect of folate supplementation  

Microsoft Academic Search

Objective:Microsatellite instability (MSI) detected in non-neoplastic mucosa of patients with ulcerative colitis has been ascribed to an excess of DNA damage associated with chronic inflammation. Folate deficiency, commonly found in patients with long-standing disease, could further contribute to this defect because folate is essential for DNA replication and repair. We evaluated MSI in the colonic mucosa of 26 patients with

Marilia L. Cravo; Cristina M. Albuquerque; L. Salazar de Sousa; Luísa M Glória; Paula Chaves; A. Dias Pereira; C. Nobre Leitao; Mario G. Quina; F. Costa Mira



Folate content in sea buckthorn berries and related products ( Hippophaë rhamnoides L. ssp. rhamnoides ): LCMS\\/MS determination of folate vitamer stability influenced by processing and storage assessed by stable isotope dilution assay  

Microsoft Academic Search

A stable isotope dilution assay was adopted for quantitation of folate vitamers in sea buckthorn berries, juice, and concentrate\\u000a using fourfold labeled folate isotopologues of the folate derivatives as the internal standards and reversed-phase liquid\\u000a chromatography–tandem mass spectrometry with electrospray ionization (LC-ESI-MS\\/MS). Processing effects and storage stability\\u000a were investigated during juice and concentrate production from sea buckthorn berries (Hippophaë rhamnoides).

Derek Gutzeit; Sabine Mönch; Gerold Jerz; Peter Winterhalter; Michael Rychlik



Revised D-A-CH intake recommendations for folate: how much is needed?  

PubMed Central

The D-A-CH reference value (D-A-CH arises from the initial letters of the common country identification for the countries Germany (D), Austria (A) and Switzerland (CH)) for folate equivalents had been set at 400??g/d for adults in the year 2000. By that time, the prevention of cardiovascular diseases through reduction of homocysteine was considered an important target of the reference value. Since that time a number of research papers revealed that in spite of an inverse association between folate-rich diet and chronic diseases, a preventive effect of folic acid intake on cardiovascular events was not supported by randomized controlled trials, and the reduction of plasma homocysteine levels to around 10–12??mol/l did not reduce the risk for thromboembolic and cardiovascular diseases in persons already affected by these diseases. These results together with the observation that folate intakes below 400??g/d result in a sufficient folate status justified a review of the current literature and—consequently—a reduction of the reference value to 300??g/d for adults. This reference value is expressed as dietary folate equivalents that take into account the difference in bioavailability between folic acid and all types of folates in food. The recommendation to take a daily supplement of 400??g of synthetic folic acid for women who intend to get pregnant and until the end of the first trimester of pregnancy is maintained. PMID:24690591

Krawinkel, M B; Strohm, D; Weissenborn, A; Watzl, B; Eichholzer, M; Barlocher, K; Elmadfa, I; Leschik-Bonnet, E; Heseker, H



Folate content in fresh-cut vegetable packed products by 96-well microtiter plate microbiological assay.  


Ready-to-eat foods have nowadays become a significant portion of the diet. Accordingly, nutritional composition of these food categories should be well-known, in particular its folate content. However, there is a broad lack of folate data in food composition tables and databases. A total of 21 fresh-cut vegetable and fruit packed products were analysed for total folate (TF) content using a validated method that relies on the folate-dependent growth of chloramphenicol-resistant Lactobacillus casei subspecies rhamnosus (NCIMB 10463). Mean TF content ranged from 10.0 to 140.9?g/100g for the different matrices on a fresh weight basis. Higher TF quantity, 140.9-70.1?g/100g, was found in spinach, rocket, watercress, chard and broccoli. Significant differences were observed between available data for fresh vegetables and fruits from food composition tables or databases and the analysed results for fresh-cut packed products. Supplied data support the potential of folate-rich fresh-cut ready-to-eat vegetables to increase folate intake significantly. PMID:25236228

Fajardo, Violeta; Alonso-Aperte, Elena; Varela-Moreiras, Gregorio



Folate and vitamin B12 levels in patients with oral lichen planus, stomatitis or glossitis.  


Forty-one patients with oral lesions and symptoms were enrolled in the study. Their ages ranged from 16 to 79 years with a mean age of 48.5 years. They were divided into two groups. Group I consisted of 25 patients with oral lichen planus and group II consisted of 16 patients with stomatitis or glossitis. Their complete blood counts, hemoglobin typing, serum and red cell folate, and serum vitamin B12 levels were studied. The results revealed low red cell folate levels in 11 out of 25 patients (44%) in group I and 9 out of 16 patients (56%) in group II. The serum vitamin B12 levels were within normal range in both groups. They were defined as having folate deficiency (n = 10), folate deficient erythropoiesis (n = 3) and folate depletion (n = 7). None of them had anemia nor macrocytes. Therefore, folate levels should be investigated in patients with oral lesions and symptoms especially those with risk factors of age, poor nutrition or systemic diseases. When suspected, daily folic acid supplements should be given. PMID:11944731

Thongprasom, K; Youngnak, P; Aneksuk, V



Folate Receptor-? in Activated Macrophages: Ligand Binding and Receptor Recycling Kinetics.  


Activated macrophages overexpress a receptor for the vitamin folic acid termed the folate receptor ? (FR-?). Because conjugation of folate to low molecular weight drugs, genes, liposomes, nanoparticles, and imaging agents has minor effects on FR binding, the vitamin can be exploited to target both therapeutic and imaging agents to activated macrophages without promoting their uptake by other healthy cells. In this paper, we characterize the binding, internalization, and recycling kinetics of FR-? on activated macrophages in inflamed tissues of rats with adjuvant-induced arthritis. Our results demonstrate that saturation of macrophage FR is achieved at injection doses of ?150-300 nmol/kg, with more rapidly perfused tissues saturating at lower doses than inflamed appendages. After binding, FR-? internalizes and recycles back to the cell surface every ?10-20 min, providing empty receptors for additional folate conjugate uptake. Because the half-life of low molecular weight folate conjugates in the vasculature is usually <1 h, these data suggest that targeting of folate conjugates to activated macrophages in vivo can be maximized by frequent dosing at conjugate concentrations that barely saturate FR (?150 nmol/kg), thereby minimizing nonspecific binding to receptor-negative tissues and maximizing the probability that unoccupied cell surface receptors will be exposed to folate-drug conjugate. PMID:25166491

Varghese, Bindu; Vlashi, Erina; Xia, Wei; Ayala Lopez, Wilfredo; Paulos, Chrystal M; Reddy, Joseph; Xu, Le-Cun; Low, Philip S



Does a high folate intake increase the risk of breast cancer?  


Although not uniformly consistent, epidemiologic studies generally suggest an inverse association between dietary intake and blood measurements of folate and breast cancer risk. However, the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening trial has recently reported for the first time a potential harmful effect of high folate intake on breast cancer risk. In this study, the risk of developing breast cancer was significantly increased by 20% in women reporting supplemental folic acid intake > or = 400 microg/d compared with those reporting no supplemental intake. Furthermore, although food folate intake was not significantly related to breast cancer risk, total folate intake, mainly from folic acid supplementation, significantly increased breast cancer risk by 32%. The data from the PLCO trial support prior observations made in epidemiologic, clinical, and animal studies suggesting that folate possesses dual modulatory effects on the development and progression of cancer depending on the timing and dose of folate intervention. Based on the lack of compelling supportive evidence, routine folic acid supplementation should not be recommended as a chemopreventive measure against breast cancer at present. PMID:17063929

Kim, Young-In



Folate intake and risk of bladder cancer: a meta-analysis of epidemiological studies.  


Epidemiological studies have reported conflicting results between folate intake and bladder cancer risk. We conducted a meta-analysis of epidemiological studies published between 1996 and June 2013 on the relationship between folate intake and bladder cancer. We quantified associations with bladder cancer using meta-analysis of risk estimates (REs) associated to the highest versus the lowest category of folate intake using random effect models. Seven cohort and six case-control studies were eligible for inclusion. A significantly decreased risk with bladder cancer was observed in overall folate intake group (RE?=?0.84; 95% CI, 0.72-0.96) and subgroup of case-control studies (RE?=?0.73; 95% CI, 0.57-0.89), but not in cohort studies (RE?=?0.96; 95% CI, 0.81-1.10) when comparing the highest with the lowest category of folate intake. No heterogeneity and publication bias were observed across studies. Although the current evidence, mainly based on data from case-control studies, supports an inverse association between folate intake and bladder cancer, additional large and well-designed cohort studies are needed before definitive conclusions can be drawn. PMID:24328495

He, Huadong; Shui, Bing



Folate and vitamin B12 status of adolescent girls in northern Nigeria.  

PubMed Central

The diets of populations in many developing countries are low in folate and vitamin B12 and a deficiency of either of these vitamins results in increased risk for cardiovascular disease and neural tube defects. The rates of neural tube defects in Nigeria are among the highest reported worldwide. Since many girls marry at an early age in northern Nigeria, we therefore determined the folate and vitamin B12 status of adolescent girls between 12 and 16 years of age in Maiduguri, Nigeria. The mean serum folate concentration for subjects was 15.3 +/- 5.2 nmol/L. Whereas only four subjects (2.4%) had serum folate concentrations lower than 6.8 nmol/L, a level indicative of negative folate balance, 9% of the subjects had serum vitamin B12 concentrations at or below 134 pmol/L, the lower limit of the reference range for their age group. Serum homocysteine was measured in 56 of the 162 subjects and the mean level was 15.9 +/- 5.0 mumol/L. The majority of subjects had serum homocysteine concentrations above the upper limit of the reference range for their age group. We conclude that the adolescent girls we studied were at greater risk for vitamin B12 deficiency than folate deficiency. This conclusion is consistent with the fact that their diet included few foods that contained vitamin B12. PMID:10946529

VanderJagt, D. J.; Spelman, K.; Ambe, J.; Datta, P.; Blackwell, W.; Crossey, M.; Glew, R. H.



Gefitinib loaded folate decorated bovine serum albumin conjugated carboxymethyl-beta-cyclodextrin nanoparticles enhance drug delivery and attenuate autophagy in folate receptor-positive cancer cells  

PubMed Central

Background Active targeting endocytosis mediated by the specific interaction between folic acid and its receptor has been a hotspot in biological therapy of many human cancers. Various studies have demonstrated that folate and its conjugates could facilitate the chemotherapeutic drug delivery into folate receptor (FR)-positive tumor cells in vitro and in vivo. In order to utilize FA-FR binding specificity to achieve targeted delivery of drugs into tumor cells, we prepared Gefitinib loaded folate decorated bovine serum albumin conjugated carboxymethyl-?-cyclodextrin nanoparticles for enhancing drug delivery in cancer cells. On this context, the aim of our study was to develop a novel nano-delivery system for promoting tumor-targeting drug delivery in folate receptor-positive Hela cells. Results We prepared folic acid (FA)-decorated bovine serum albumin (BSA) conjugated carboxymethyl-?-cyclodextrin (CM-?-CD) nanoparticles (FA-BSA-CM-?-CD NPs) capable of entrapping a hydrophobic Gefitinib. It was observed that nanoparticles are monodisperse and spherical nanospheres with an average diameter of 90.2 nm and negative surface charge of ?18.6 mV. FA-BSA-CM-?-CD NPs could greatly facilitate Gefitinib uptake and enhance the toxicity to folate receptor-positive Hela cells. Under the reaction between FA and FR, Gefitinib loaded FA-BSA-CM-?-CD NPs induced apoptosis of Hela cells through elevating the expression of caspase-3 and inhibited autophagy through decreasing the expressing of LC3. It also confirmed that clathrin-mediated endocytosis and macropinocytosis exerted great influence on the internalization of both NPs. Conclusions These results demonstrated that FA may be an effective targeting molecule and FA-BSA-CM-?-CD NPs provided a new strategy for the treatment of human cancer cells which over-expressed folate receptors. PMID:25358257



Comparative folate metabolism in humans and malaria parasites (part II): activities as yet untargeted or specific to Plasmodium  

PubMed Central

The folate pathway represents a powerful target for combating rapidly dividing systems such as cancer cells, bacteria and malaria parasites. Whereas folate metabolism in mammalian cells and bacteria has been studied extensively, it is understood less well in malaria parasites. In two articles, we attempt to reconstitute the malaria folate pathway based on available information from mammalian and microbial systems, in addition to Plasmodium-genome-sequencing projects. In part I, we focused on folate enzymes that are already used clinically as anticancer drug targets or that are under development in drug-discovery programs. In this article, we discuss mammalian folate enzymes that have not yet been exploited as potential drug targets, and enzymes that function in the de novo folate-synthesis pathway of the parasite – a particularly attractive area of attack because of its absence from the mammalian host. PMID:15936248

Nzila, Alexis; Ward, Steve A.; Marsh, Kevin; Sims, Paul F.G.; Hyde, John E.



Preparation and biodistribution of 188Re-labeled folate conjugated human serum albumin magnetic cisplatin nanoparticles (188Re-folate-CDDP/HSA MNPs) in vivo  

PubMed Central

Background The purpose of this study was to develop intraperitoneal hyperthermic therapy based on magnetic fluid hyperthermia, nanoparticle-wrapped cisplatin chemotherapy, and magnetic particles of albumin. In addition, to combine the multiple-killing effects of hyperthermal targeting therapy, chemotherapy, and radiotherapy, the albumin-nanoparticle surfaces were linked with radionuclide 188Re-labeled folic acid ligand (188Re-folate-CDDP/HSA). Methods Human serum albumin was labeled with 188Re using the pre-tin method. Reaction time and optimal conditions of labeling were investigated. The particles were intravenously injected into mice, which were sacrificed at different time points. Radioactivity per gram of tissue of percent injected dose (% ID/g) was measured in vital organs. The biodistribution of 188Re-folate-CDDP/HAS magnetic nanoparticles was assessed. Results Optimal conditions for 188Re-labeled folate-conjugated albumin combined with cisplatin magnetic nanoparticles were: 0.1 mL of sodium gluconate solution (0.3 mol/L), 0.1 mL of concentrated hydrochloric acid with dissolved stannous chloride (10 mg/mL), 0.04 mL of acetic acid buffer solution (pH 5, 0.2 mol/L), 30 mg of folate-conjugated albumin combined with cisplatin magnetic nanoparticles, and 188ReO4 eluent (0.1 mL). The rate of 188Re-folate-CDDP-HSA magnetic nanoparticle formation exceeded 90%, and radiochemical purity exceeded 95%. The overall labeling rate was 83% in calf serum at 37°C. The major uptake tissues were the liver, kidney, intestine, and tumor after the 188Re-folate-CDDP/HSA magnetic nanoparticles were injected into nude mice. Uptake of 188Re-folate-CDDP/HSA magnetic nanoparticles increased gradually after injection, peaked at 8 hours with a value of 8.83 ± 1.71, and slowly decreased over 24 hours in vivo. Conclusion These results indicate that 188Re-folate-CDDP/HSA magnetic nanoparticles can be used in radionuclide-targeted cancer therapy. Surface-modified albumin nanoparticles with folic acid ligand-labeled radionuclide (188Re) were successfully prepared, laying the foundation for a triple-killing effect of thermotherapy, chemotherapy, and radiation therapy. PMID:22163161

Tang, Qiu-Sha; Chen, Dao-Zhen; Xue, Wen-Qun; Xiang, Jing-Ying; Gong, Yong-Chi; Zhang, Li; Guo, Cai-Qin



Natural folates from biofortified tomato and synthetic 5-methyl-tetrahydrofolate display equivalent bioavailability in a murine model.  


Folate deficiency is a global health problem related to neural tube defects, cardiovascular disease, dementia, and cancer. Considering that folic acid (FA) supply through industrialized foods is the most successful intervention, limitations exist for its complete implementation worldwide. Biofortification of plant foods, on the other hand, could be implemented in poor areas as a complementary alternative. A biofortified tomato fruit that accumulates high levels of folates was previously developed. In this study, we evaluated short-term folate bioavailability in rats infused with this folate-biofortified fruit. Fruit from tomato segregants hyperaccumulated folates during an extended ripening period, ultimately containing 3.7-fold the recommended dietary allowance in a 100-g portion. Folate-depleted Wistar rats separated in three groups received a single dose of 1 nmol of folate/g body weight in the form of lyophilized biofortified tomato fruit, FA, or synthetic 5-CH3-THF. Folate bioavailability from the biofortified tomato was comparable to that of synthetic 5-CH3-THF, with areas under the curve (AUC(0-?)) of 2,080?±?420 and 2,700?±?220 pmol?·?h/mL, respectively (P?=?0.12). Whereas, FA was less bioavailable with an AUC(0-?) of 750?±?10 pmol?·?h/mL. Fruit-supplemented animals reached maximum levels of circulating folate in plasma at 2 h after administration with a subsequent steady decline, while animals treated with FA and synthetic 5-CH3-THF reached maximum levels at 1 h. Pharmacokinetic parameters revealed that biofortified tomato had slower intestinal absorption than synthetic folate forms. This is the first study that demonstrates the bioavailability of folates from a biofortified plant food, showing its potential to improve folate deficiency. PMID:24445671

Castorena-Torres, Fabiola; Ramos-Parra, Perla A; Hernández-Méndez, Rogelio V; Vargas-García, Andrés; García-Rivas, Gerardo; de la Garza, Rocío I Díaz



Intake and blood concentrations of folate and their association with health-related behaviors in Korean college students  

PubMed Central

The purpose of this study is to assess folate intake, and serum and red blood cell (RBC) folate concentrations, and investigate the association between folate status and health-related behaviors among Korean college students. A total of 169 students, aged between 18 and 27 years, participated in this study. Dietary intake data were collected by trained interviewers using a 24-hour recall method for three non-consecutive days in 2009. Information on health-related behaviors was obtained by a self-administered questionnaire. Serum and RBC folate concentrations were measured by microbiological assay. The average intakes of folate were 456 µgDFE and 347 µgDFE in male and female students, respectively. While the average serum folate concentration was significantly lower in male students (8.9 ng/mL) compared to female students (12.5 ng/mL), RBC concentrations were not significantly different between male (398.6 ng/mL) and female students (405.3 ng/mL). In male students, low serum folate concentrations were associated with total folate intake less than the Estimated Average Requirement, non-use of folic acid supplements, smoking, alcohol drinking at least once a week and low physical activity. In female students, low serum folate concentrations were associated with smoking and alcohol drinking at least two drinks at a time and BMI ? 25. Alcohol drinking and low physical activity were also associated with low RBC folate concentrations in both male and female students. In order to improve folate nutritional status of college students, the practice of desirable health-related behaviors, such as non-smoking, moderate alcohol drinking, regular physical activity, and maintenance of healthy BMI should be encouraged along with consumption of folate-rich foods and supplements. PMID:23766883

Jang, Han-Byul; Han, Young-Hee; Piyathilake, Chandrika J; Kim, Heon



Folate-targeted nanoparticle delivery of chemo- and radiotherapeutics for the treatment of ovarian cancer peritoneal metastasis.  


Peritoneal metastasis is a major cause of morbidity and mortality in ovarian cancer. While intraperitoneal chemotherapy and radiotherapy have shown favorable clinical results, both are limited by their non-targeted nature. We aimed to develop a biologically targeted nanoparticle therapeutic for the treatment of ovarian cancer peritoneal metastasis. Folate-targeted nanoparticles encapsulating chemotherapy and/or radiotherapy were engineered. Paclitaxel (Ptxl) was used as the chemotherapeutic and yittrium-90 ((90)Y) was employed as the therapeutic radioisotope. Folate was utilized as the targeting ligand as most ovarian cancers overexpress the folate receptor. Nanoparticle characterization studies showed monodispersed particles with controlled Ptxl release. Folate targeting ligand mediated the uptake of NPs into tumor cells. In vitro efficacy studies demonstrated folate-targeted NPs containing chemoradiotherapy was the most effective therapeutic compared to folate-targeted NPs containing a single therapeutic or any non-targeted NP therapeutics. In vivo efficacy studies using an ovarian peritoneal metastasis model showed that folate-targeted NP therapeutics were significantly more effective than non-targeted NP therapeutics. Among the folate-targeted therapeutics, the NP containing chemoradiotherapy appeared to be the most effective. Our results suggest that folate-targeted nanoparticles containing chemoradiotherapy have the potential as a treatment for ovarian peritoneal metastasis. PMID:21843904

Werner, Michael E; Karve, Shrirang; Sukumar, Rohit; Cummings, Natalie D; Copp, Jonathan A; Chen, Ronald C; Zhang, Tian; Wang, Andrew Z



Expression and alternative splicing of folate pathway genes in HapMap lymphoblastoid cell lines  

PubMed Central

Aim Folate is vital for cell growth and development through its important role in one-carbon metabolism - an essential process in the synthesis of amino acids and nucleic acids. Folate pathway genes have been considered as therapeutic targets of drugs for the treatment of cancer and other diseases. Racial and ethnic disparities of folate metabolism and outcome of antifolate therapies have been reported. In this study, we evaluate the genetic regulation for expression and alternative splicing of folate related genes in HapMap lymphoblastoid cell lines (LCLs) of individuals of European and African descent. Materials & methods Gene and exon level expression and alternative splicing of folate pathway genes were compared in LCLs derived from the Centre d'Etude du Polymorphisme Humain (CEPH) from Utah (CEU) and the Yoruba from Ibadan (YRI) using a permutation-based test. A genome-wide association study was performed to search for SNPs associated with folate pathway gene expressions and alternative splicing in the combined population samples. Results A total of 52 folate pathway genes were evaluated in the analysis of which 46 were expressed in the LCLs. There were 12 genes (26%) with differential gene-level expression and 23 genes (50%) with differential alternative splicing for exons or UTRs between the CEU and the YRI (permutation p ? 0.05). The expression level of FPGS and the splicing indices of eight genes (ATP13A2, ASCC3L1, IFIH1, SMARCA5, SMARCA2, SETX, DDX52 and RUVBL2) were found to be associated with SNP genotypes in the combined populations (p < 3.2 × 10-8, Bonferroni corrected p < 0.05). Conclusion Our study suggests that LCLs are an in vitro system suitable to evaluate the expression levels of folate pathway genes. The differential transcript-level expressions and the differentially alternative splicing events of exons or UTRs and associated SNP markers in 2 populations will enhance our understanding of the folate pathway and, thus, facilitate research in the areas of nutrition and folate metabolism. PMID:19374514

Duan, Shiwei; Huang, R Stephanie; Zhang, Wei; Mi, Shuangli; Bleibel, Wasim K; Kistner, Emily O; Cox, Nancy J; Dolan, M Eileen



Folate deficiency-induced oxidative stress contributes to neuropathy in young and aged zebrafish - Implication in neural tube defects and Alzheimer's diseases.  


Folate is a nutrient essential for the development, function and regeneration of nervous systems. Folate deficiency has been linked to many neurological disorders including neural tube defects in fetus and Alzheimer's diseases in the elderly. However, the etiology underlying these folate deficiency-associated diseases is not completely understood. In this study, zebrafish transgenic lines with timing and duration-controllable folate deficiency were developed by ectopically overexpressing a recombinant EGFP-?-glutamyl hydrolase (?GH). Impeded neural crest cell migration was observed in the transgenic embryos when folate deficiency was induced in early stages, leading to defective neural tube closure and hematopoiesis. Adding reduced folate or N-acetylcysteine reversed the phenotypic anomalies, supporting the causal link between the increased oxidative stress and the folate deficiency-induced abnormalities. When folate deficiency was induced in aged fish accumulation of beta-amyloid and phosphorylated Tau protein were found in the fish brain cryo-sections. Increased autophagy and accumulation of acidic autolysosome were apparent in folate deficient neuroblastoma cells, which were reversed by reduced folate or N-acetylcysteine supplementation. Decreased expression of cathepsin B, a lysosomal protease, was also observed in cells and tissue with folate deficiency. We concluded that folate deficiency-induced oxidative stress contributed to the folate deficiency-associated neuropathogenesis in both early and late stages of life. PMID:25131448

Kao, Tseng-Ting; Chu, Chia-Yi; Lee, Gang-Hui; Hsiao, Tsun-Hsien; Cheng, Nai-Wei; Chang, Nan-Shan; Chen, Bing-Hung; Fu, Tzu-Fun



Hypericin: chemical synthesis and biosynthesis.  


Hypericin is one of the most important phenanthoperylene quinones extracted mainly from plants of the genus Hypericum belonging to the sections Euhypericum and Campylosporus of Keller's classification. Widespread attention to the antiviral and anti-tumor properties of hypericin has spurred investigations of the chemical synthesis and biosynthesis of this unique compound. However, the synthetic strategies are challenging for organic and biological chemists. In this review, specific significant advances in total synthesis, semi-synthesis, and biosynthesis in the past decades are summarized. PMID:24636057

Huang, Lin-Fang; Wang, Zeng-Hui; Chen, Shi-Lin



Auxin biosynthesis and storage forms  

PubMed Central

The plant hormone auxin drives plant growth and morphogenesis. The levels and distribution of the active auxin indole-3-acetic acid (IAA) are tightly controlled through synthesis, inactivation, and transport. Many auxin precursors and modified auxin forms, used to regulate auxin homeostasis, have been identified; however, very little is known about the integration of multiple auxin biosynthesis and inactivation pathways. This review discusses the many ways auxin levels are regulated through biosynthesis, storage forms, and inactivation, and the potential roles modified auxins play in regulating the bioactive pool of auxin to affect plant growth and development. PMID:23580748

Strader, Lucia C.



Lower serum folate is associated with development and invasiveness of gastric cancer  

PubMed Central

AIM: To evaluate the associations of serum folate level with development, invasiveness and patient survival of gastric cancer. METHODS: In this nested case-control study, patients with newly diagnosed gastric cancer undergoing gastrectomy were enrolled, and patients receiving chemotherapy prior to surgery, with other concurrent malignancy, or of the aboriginal and alien populations were excluded. In total, 155 gastric cancer patients and 149 healthy controls were enrolled for determination of serum folate levels and their correlation with gastric cancer. Using the median value of serum folate computed among the overall population as the cutoff value, the associations between serum folate and gastric cancer in all cases and different age and gender subgroups were analyzed by multivariate logistic regression analysis. In the patient cohort of gastric cancer, receiver-operating characteristic analyses were performed to calculate the best cutoff values of serum folate, and the associations between serum folate levels and clinicopathological features were further analyzed by multivariate regression analysis. Survival analyses were conducted using the Cox proportional hazards model. RESULTS: The mean serum folate level was significantly lower in gastric cancer patients than that in controls (3.71 ± 0.30 ng/mL vs 8.00 ± 0.54 ng/mL, P < 0.01), and folate levels were consistently lower in gastric cancer patients regardless of age and gender (all P < 0.01). Using the median serum folate value as the cutoff value, low serum folate was significantly associated with gastric cancer risk in the whole population (OR = 19.77, 95%CI: 10.54-37.06, P < 0.001) and all strata (age < 60 years OR = 17.39, 95%CI: 7.28-41.54, age ? 60 years (OR = 21.67, 95%CI: 8.27-56.80), males (OR = 17.95, 95%CI: 7.93-40.62), and females (OR = 20.95, 95%CI: 7.66-57.31); all P < 0.001. In the patient cohort of gastric cancer, the respective cutoff values showed that low serum folate levels were significantly associated with serosal invasion (OR = 2.54, 95%CI: 1.23-5.23), lymphatic invasion (OR = 2.23, 95%CI: 1.17-4.26), and liver metastasis (OR = 6.67, 95%CI: 1.28-34.91) of gastric cancer (all P < 0.05). Serum folate level below 1.90 ng/mL was associated with poor patient survival (HR = 1.84, 95%CI: 1.04-3.27, P < 0.05) in univariate analysis. CONCLUSION: Lower serum folate levels were significantly associated with gastric cancer development and invasive phenotypes. The role of folate depletion in gastric cancer invasion warrants further study. PMID:25170216

Lee, Teng-Yu; Chiang, En-Pei; Shih, Yin-Ting; Lane, Hsien-Yuan; Lin, Jaw-Town; Wu, Chun-Ying



Are vitamin B12 and folate deficiency clinically important after roux-en-Y gastric bypass?  


Although iron, vitamin B12, and folate deficiency have been well documented after gastric bypass operations performed for morbid obesity, there is surprisingly little information on either the natural course or the treatment of these deficiencies in Roux-en-Y gastric bypass (RYGB) patients. During a 10-year period, a complete blood count and serum levels of iron, total iron-binding capacity, vitamin B12, and folate were obtained in 348 patients preoperatively and postoperatively at 6-month intervals for the first 2 years, then annually thereafter. The principal objectives of this study were to determine how readily patients who developed metabolic deficiencies after Roux-en-Y gastric bypass responded to postoperative supplements of the deficient micronutrient and to learn whether the risk of developing these deficiencies decreases over time. Hemoglobin and hematocrit levels were significantly decreased at all postoperative intervals in comparison to preoperative values. Moreover, at each successive interval through 5 years, hemoglobin and hematocrit were decreased significantly compared to the preceding interval. Folate levels were significantly increased compared to preoperative levels at all time intervals. Iron and vitamin B12 levels were lower than preoperative measurements and remained relatively stable postoperatively. Half of the low hemoglobin levels were not associated with iron deficiency. Taking multivitamin supplements resulted in a lower incidence of folate deficiency but did not prevent iron or vitamin B12 deficiency. Oral supplementation of iron and vitamin B12 corrected deficiencies in 43% and 81% of cases, respectively. Folate deficiency was almost always corrected with multivitamins alone. No patient had symptoms that could be attributed to either vitamin B12 or folate deficiency Conversely, many patients had symptoms of iron deficiency and anemia. Lack of symptoms of vitamin B12 and folate deficiency suggests that these deficiencies are not clinically important after RYGB. Conversely, iron deficiency and anemia are potentially serious problems after RYGB, particularly in younger women. Hence we recommend prophylactic oral iron supplements to premenopausal women who undergo RYGB. PMID:9843603

Brolin, R E; Gorman, J H; Gorman, R C; Petschenik, A J; Bradley, L J; Kenler, H A; Cody, R P



Folate Deficiency Is Associated With Oxidative Stress, Increased Blood Pressure, and Insulin Resistance in Spontaneously Hypertensive Rats  

PubMed Central

BACKGROUND The role of folate deficiency and associated hyperhomocysteinemia in the pathogenesis of metabolic syndrome is not fully established. In the current study, we analyzed the role of folate deficiency in pathogenesis of the metabolic syndrome in the spontaneously hypertensive rat (SHR). METHODS Metabolic and hemodynamic traits were assessed in SHR/Ola rats fed either folate-deficient or control diet for 4 weeks starting at the age of 3 months. RESULTS Compared to SHRs fed a folate-replete diet, SHRs fed a folate-deficient diet showed significantly reduced serum folate (104±5 vs. 11±1 nmol/L, P < 0.0005) and urinary folate excretion (4.3±0.6 vs. 1.2±0.1 nmol/16h, P < 0.0005) together with a near 3-fold increase in plasma total homocysteine concentration (4.5±0.1 vs 13.1±0.7 ?mol/L, P < 0.0005), ectopic fat accumulation in liver, and impaired glucose tolerance. Folate deficiency also increased systolic blood pressure by approximately 15mm Hg (P < 0.01). In addition, the low-folate diet was accompanied by significantly reduced activity of antioxidant enzymes and increased concentrations of lipoperoxidation products in liver, renal cortex, and heart. CONCLUSIONS These findings demonstrate that the SHR model is susceptible to the adverse metabolic and hemodynamic effects of low dietary intake of folate. The results are consistent with the hypothesis that folate deficiency can promote oxidative stress and multiple features of the metabolic syndrome that are associated with increased risk for diabetes and cardiovascular disease. PMID:23382337



Transcriptional control of flavonoid biosynthesis  

PubMed Central

Flavonoids are plant secondary polyphenolic metabolites and fulfil many vital biological functions, offering a valuable metabolic and genetic model for studying transcriptional control of gene expression. Arabidopsis thaliana mainly accumulates 3 types of flavonoids, including flavonols, anthocyanins, and proanthocyanidins (PAs). Flavonoid biosynthesis involves a multitude of well-characterized enzymatic and regulatory proteins. Three R2R3-MYB proteins (MYB11, MYB12, and MYB111) control flavonol biosynthesis via activating the early biosynthetic steps, whereas the production of anthocyanins and PAs requires the MYB-bHLH-WD40 (MBW) complex to activate the late biosynthetic genes. Additional regulators of flavonoid biosynthesis have recently come to light, which interact with R2R3-MYBs or bHLHs to organize or disrupt the formation of the MBW complex, leading to enhanced or compromised flavonoid production. This mini-review gives an overview of how these novel players modulate flavonoid metabolism and thus plant developmental processes and further proposes a fine-tuning mechanism to complete the complex regulatory network controlling flavonoid biosynthesis. PMID:24393776

Li, Shutian



Post-transcriptional regulation of the human reduced folate carrier as a novel adaptive mechanism in response to folate excess or deficiency  

PubMed Central

The RFC (reduced folate carrier) is the principal mechanism by which folates and clinically used antifolates are delivered to mammalian cells. hRFC (human RFC) is subject to complex transcriptional controls and exists as homo-oligomer. To explore the post-transcriptional regulation of hRFC by exogenous folates, hRFC-null HeLa cells were stably transfected with hRFC under control of a constitutive promoter. hRFC transcripts and the total membrane protein increased with increasing LCV [(6R,S)5-formyl tetrahydrofolate (leucovorin)] with a maximum at 20 nM LCV, attributable to reduced turnover of hRFC transcripts. hRFC homo-oligomerization was unaffected by increasing LCV. Cell surface hRFC paralleled [3H]methotrexate transport and increased from 0.5 to 2 nM LCV, and then decreased (~2-fold) with increasing LCV up to 20 nM. hRFC was localized to the cell surface at low LCV concentrations (0.5–1.5 nM). However, at higher LCV concentrations, significant intracellular hRFC was localized to the ER (endoplasmic reticulum), such that at 20 nM LCV, intracellular hRFC was predominated. Our results demonstrate a novel post-transcriptional regulation of hRFC involving: (i) increased hRFC transcripts and proteins, accompanying increased extracellular folates, attributable to differences in hRFC transcript stabilities; and (ii) increased retention of hRFC in the ER under conditions of folate excess, because of impaired intracellular trafficking and plasma membrane targeting. PMID:24949876

Hou, Zhanjun; Orr, Steve; Matherly, Larry H.



Folate receptor-? constitutes a marker for human proinflammatory monocytes.  


Activated macrophages are commonly involved in the pathogenesis of inflammatory and autoimmune diseases and have been frequently reported to overexpress FR-?. Although FR-targeted therapies aimed at eliminating activated macrophages have shown promise for treating inflammatory diseases, little work has been performed to evaluate whether other hematopoietic cells might also express FR-?. Analysis of peripheral blood cells with a mAb to human FR-? reveals that only monocytes express FR-?. Molecular characterization of these circulating monocytes further demonstrates that solely the classic/proinflammatory subset (CD14(high)CD16(-)) expresses the FR and that only CD14(high)CD16(-) FR-?(+) monocytes also display the ability to bind folate-linked molecules. Confirmation that this subset of monocytes indeed constitutes the proinflammatory subpopulation was obtained by demonstrating coexpression of FR-? with other proinflammatory markers, including CCR2 and HLA-DR. Synovial monocytes from the joints of patients with RA were also shown to express FR-?. As inhibition of the chemotaxis of proinflammatory monocytes into sites of inflammation has been explored frequently as a means of controlling autoimmune diseases, demonstration that FR-? is uniquely expressed on this proinflammatory subpopulation offers a new strategy to suppress migration of inflammatory monocytes into sites of inflammation. PMID:25015955

Shen, Jiayin; Hilgenbrink, Andrew R; Xia, Wei; Feng, Yang; Dimitrov, Dimiter S; Lockwood, Michael B; Amato, Robert J; Low, Philip S



Cell uptake enhancement of folate targeted polymer coated magnetic nanoparticles.  


Dual targeted drug delivery systems represent a potential platform for developing efficient vector to tumor sites. In this study we evaluated a folate- and magnetic-targeted nanocarriers based on 10 nm iron oxide nanodomais coated with the properly synthesized and characterized folic acid (FA)-functionalized amphiphilic copolymer PHEA-PLA-PEG-FA. FA was chemically conjugated to one end of diamino-polyethylene glycol of 2000 Da, in order to ensure its exposition on the polymer coated magnetic nanoparticles (MNPs-FA). The prepared nanoparticles have been exhaustively characterized by different methods, including DLS, SEM, FT-IR and magnetic measurements. Magnetic nanoparticles showed dimension of about 37 nm with a narrow size distribution and a characteristic superparamagnetic behaviour. The lack of cytotoxicity of MNPs-FA and MNPs was assessed both on MCF7 cells, used as a model tumor cell line, and on 16HBE, used as normal human cell model, by evaluating cell viability using MTS assay, while the preferential internalization of MNPs-FA into tumor cells rather that into normal cells was confirmed by the quantization of internalized iron oxide. Uptake studies were also performed in the presence of a permanent magnet in order to verify the synergistic effect of magnetic field in enhancing the internalization of magnetic nanoparticles. Finally, real-time confocal microscopy experiments were carried out to further confirmed that FA ligand enhances the MNPs-FA accumulation into cancer cell cytoplasm. PMID:23858959

Licciardi, Mariano; Scialabba, Cinzia; Cavallaro, Gennara; Sangregorio, Claudio; Fantechi, Elvira; Giammona, Gaetano



Intakes of Alcohol and Folate During Adolescence and Risk of Proliferative Benign Breast Disease  

PubMed Central

OBJECTIVES: To examine the combined effect of alcohol and folate intake during adolescence on the risk of proliferative benign breast disease (BBD). METHODS: We used data from 29?117 women in the Nurses’ Health Study II who completed both adolescent alcohol consumption questions in 1989 and an adolescent diet questionnaire in 1998. A total of 659 women with proliferative BBD diagnosed between 1991 and 2001 were confirmed by central pathology review. Cox proportional hazards models were used to estimate hazard ratios and 95% confidence intervals (CIs), adjusted for established risk factors of breast cancer. RESULTS: Adolescent alcohol consumption was dose-dependently associated with an increased risk of proliferative BBD (hazard ratio = 1.15 per 10 g/day consumption; 95% CI, 1.03–1.28). There was no significant association between adolescent folate intake and the risk of proliferative BBD. Stratified analyses showed that each 10-g/day alcohol intake during adolescence was associated with a 21% (95% CI, 1.01–1.45) increase in the risk of proliferative BBD among women with low folate intake during adolescence, which was not significantly different from the alcohol-associated risk among women with moderate and high folate intake during adolescence (P for interaction = 0.18). CONCLUSIONS: Adolescent alcohol consumption is associated with increased risk of proliferative BBD, which may not be reduced by increased folate intake during adolescence. PMID:22492774

Liu, Ying; Tamimi, Rulla M.; Berkey, Catherine S.; Willett, Walter C.; Collins, Laura C.; Schnitt, Stuart J.; Connolly, James L.



Genetic variants in the folate pathway and risk of childhood acute lymphoblastic leukemia  

PubMed Central

Objective Folate is involved in the one-carbon metabolism that plays an essential role in the synthesis, repair and methylation of DNA. We examined whether child’s germline genetic variation in the folate pathway is associated with childhood acute lymphoblastic leukemia (ALL), and whether periconception maternal folate and alcohol intake modify the risk. Methods Seventy-six single nucleotide polymorphisms (SNPs), including 66 haplotype-tagging SNPs in 10 genes (CBS, DHFR, FOLH1, MTHFD1, MTHFR, MTR, MTRR, SHMT1, SLC19A1, and TYMS) were genotyped in 377 ALL cases and 448 controls. Log-additive associations between genotypes and ALL risk were adjusted for age, sex, Hispanic ethnicity (when appropriate), and maternal race. Results Single and haplotype SNPs analyses showed statistically significant associations between SNPs located in (or adjacent to) CBS, MTRR, TYMS/ENOFS and childhood ALL. Many regions of CBS were associated with childhood ALL in Hispanics and non-Hispanics (P <0.01). Levels of maternal folate intake modified associations with SNPs in CBS, MTRR, and TYMS. Conclusion Our data suggest the importance of genetic variability in the folate pathway and childhood ALL risk. PMID:21748308

Metayer, Catherine; Scelo, Ghislaine; Chokkalingam, Anand P.; Barcellos, Lisa F.; Aldrich, Melinda C.; Chang, Jeffrey S.; Guha, Neela; Urayama, Kevin Y.; Hansen, Helen M.; Block, Gladys; Kiley, Vincent; Wiencke, John K.; Wiemels, Joseph L.; Buffler, Patricia A.



Effect of cisplatin on intracellular folate compounds in L1210 cells  

SciTech Connect

The biologically active form of the anticancer agent Cisplatin, cis-diamminediaquaplatinum(II)-ion, reacts rapidly with tetrahydrofolate at pH 7 and 37/sup 0/C to form a stable complex. The purified platinum-tetrahydrofolate derivative has also been shown to inhibit the dihydrofolate reductase and the folate transport system of L1210 cells. To determine whether platinum-tetrahydrofolate complex formation would be observed under in vivo conditions, intracellular folates of L1210 cells were labeled by growth on (/sup 3/H)folate and then analyzed by reverse phase HPLC. No evidence for the intracellular formation of platinum tetrahydrofolate was found in cells grown for 48 in the presence of 10/sup -7/ M Cisplatin. The profile of intracellular folate monoglutamates, however, was distinctly different. The level of 5,10-methenyltetrahydrofolate was decreased, and increases were seen in the levels of tetrahydrofolate and its 5-formyl and 10-formyl derivatives. These changes in intracellular folates are compared to those seen when L1210 cells are treated with the antifolate drug, Methotrexate, and the implications for cell kill are examined.

Vitols, K.S.; Monteiano, Y.D.



Changing micronutrient intake through (voluntary) behaviour change. The case of folate.  


The objective of this study was to relate behaviour change mechanisms to nutritionally relevant behaviour and demonstrate how the different mechanisms can affect attempts to change these behaviours. Folate was used as an example to illuminate the possibilities and challenges in inducing behaviour change. The behaviours affecting folate intake were recognised and categorised. Behaviour change mechanisms from "rational model of man", behavioural economics, health psychology and social psychology were identified and aligned against folate-related behaviours. The folate example demonstrated the complexity of mechanisms influencing possible behavioural changes, even though this only targets the intake of a single micronutrient. When considering possible options to promote folate intake, the feasibility of producing the desired outcome should be related to the mechanisms of required changes in behaviour and the possible alternatives that require no or only minor changes in behaviour. Dissecting the theories provides new approaches to food-related behaviour that will aid the development of batteries of policy options when targeting nutritional problems. PMID:22407133

Jensen, Birger B; Lähteenmäki, Liisa; Grunert, Klaus G; Brown, Kerry A; Timotijevic, Lada; Barnett, Julie; Shepherd, Richard; Raats, Monique M



Folate and vitamin B12 status of a multiethnic adult population.  

PubMed Central

BACKGROUND: Folic acid and vitamin B12 are of particular interest for their diverse biological functions and preventive roles in many prevalent chronic diseases. However, ethnic differences on the status of these vitamins have not been investigated among multiethnic adult college students. METHODS: A cross-sectional study (n = 177) was conducted to determine the dietary intakes and levels of serum concentrations of folate and vitamin B12 among triethnic college students-non-Hispanic white, Hispanic and non-Hispanic black. Dietary intake was assessed using a validated food frequency questionnaire, and serum was analyzed for folate and vitamin B12 using standardized methods. RESULTS: Mean intakes of both vitamins without supplementation was higher (P < 0.05) among non-Hispanic white males than females, and non-Hispanic white and non-Hispanic black males and females. Non-Hispanic white females had a significantly lower mean dietary intake of vitamin B12 than the females of other ethnic groups (P < 0.01). There was a positive correlation between B12 intake and serum concentrations. More than 52% of the females did not meet the required folate intake of 400 microg/day. CONCLUSIONS: The data suggest that there was no difference in overall mean intake of folate and vitamin B12 or serum concentrations in regard to gender or ethnicity. One-fourth of the female subjects failed to meet the recommended folate intake when supplement was excluded. PMID:16532981

Nath, Subrata D.; Koutoubi, Samer; Huffman, Fatma G.



Use of the deoxyuridine suppression test to evaluate localized folate deficiency in rat colonic epithelium.  


In this study the deoxyuridine suppression test (dUST) was performed on isolated rat colonocytes to establish its value as an indicator of folate status in the colonic epithelium. [3H]thymidine incorporation into DNA was suppressed greater than 90% by deoxyuridine (dU) concentrations greater than 2.5 mumol/L. Preincubation of cells with 5-fluorouracil (1-100 mumol/L) but not methotrexate (10-100 mumol/L) resulted in a significant decrease in the degree of suppression. The dUST performed on colonocytes from folate-deficient animals displayed less suppression than on colonocytes from folate-replete animals (P less than 0.05). The abnormal degree of suppression was corrected by adding 100 mumol folinic acid/L. There was a negative correlation between the degree of suppression and the folate concentration of the colonic epithelium (P less than 0.001). These data indicate that the dUST is useful for detecting folate deficiency in the colonic epithelium and may therefore be valuable in assessing a deficiency state localized to that epithelium. PMID:2035472

Cravo, M L; Mason, J B; Selhub, J; Rosenberg, I H



Update and new concepts in vitamin responsive disorders of folate transport and metabolism.  


Derivatives of folic acid are involved in transfer of one-carbon units in cellular metabolism, playing a role in synthesis of purines and thymidylate and in the remethylation of homocysteine to form methionine. Five inborn errors affecting folate transport and metabolism have been well studied: hereditary folate malabsorption, caused by mutations in the gene encoding the proton-coupled folate transporter (SLC46A1); glutamate formiminotransferase deficiency, caused by mutations in the FTCD gene; methylenetetrahydrofolate reductase deficiency, caused by mutations in the MTHFR gene; and functional methionine synthase deficiency, either as the result of mutations affecting methionine synthase itself (cblG, caused by mutations in the MTR gene) or affecting the accessory protein methionine synthase reductase (cblE, caused by mutations in the MTRR gene). Recently additional inborn errors have been identified. Cerebral folate deficiency is a clinically heterogeneous disorder, which in a few families is caused by mutations in the FOLR1 gene. Dihydrofolate reductase deficiency is characterized by megaloblastic anemia and cerebral folate deficiency, with variable neurological findings. It is caused by mutations in the DHFR gene. Deficiency in the trifunctional enzyme containing methylenetetrahydrofolate dehydrogenase, methenyltetrahydrofolate cyclohydrolase and formyltetrahydrofolate synthetase activities, has been identified in a single patient with megaloblastic anemia, atypical hemolytic uremic syndrome and severe combined immune deficiency. It is caused by mutations in the MTHFD1 gene. PMID:22108709

Watkins, David; Rosenblatt, David S



Diagnosis and management of cerebral folate deficiency. A form of folinic acid-responsive seizures.  


Folinic acid-responsive seizures (FARS) are a rare treatable cause of neonatal epilepsy. They have characteristic peaks on CSF monoamine metabolite analysis, and have mutations in the ALDH7A1 gene, characteristically found in pyridoxine-dependent epilepsy. There are case reports of patients presenting with seizures at a later age, and with folate deficiency due to different mechanisms with variable response to folinic acid supplementation. Here, we report 2 siblings who presented with global developmental delay and intractable seizures who responded clinically to folinic acid therapy. Their work-up included metabolic and genetic testing. The DNA sequencing was carried out for the ALDH7A1 gene, and the folate receptor 1 (FOLR1) gene. They had very low 5-methyltetrahydrofolate (5-MTHF) in CSF with no systemic folate deficiency and no characteristic peaks on neurotransmitter metabolite chromatogram. A novel mutation in the FOLR1 gene was found. The mutation in this gene is shown to affect CSF folate transport leading to cerebral folate deficiency. The response to treatment with folinic acid was dramatic with improvement in social interaction, mobility, and complete seizure control. We should consider the possibility of this treatable condition in appropriate clinical circumstances early, as diagnosis with favorable outcome depends on the specialized tests. PMID:25274592

Al-Baradie, Raidah S; Chaudhary, Mohammed W



A relationship between vitamin B sub 12 , folate, ascorbic acid, and mercury metabolism  

SciTech Connect

The effect of megadoses of vitamin B{sub 12}, folate, and vitamin C on the in vivo methylation of mercuric chloride was studied in guinea pigs. The incorporation of high levels of vitamin B{sub 12}, folate, and vitamin C resulted in a decrease in both inorganic mercury and methylmercury concentrations in all tissues except the lungs and heart compared to controls. However, percent methylmercury levels tended to increase with vitamin treatment. The addition of megadoses of vitamin B{sub 12} fed either singularly or in combination with the other vitamins resulted in increased methylmercury concentrations in the liver, spleen, and kidney tissues of the guinea pig. Moreover, percent methylmercury levels increased with B{sub 12} treatment in the liver, heart, and kidney. Incorporation of high levels of folate into the dietary regime also affected the mercury methylation process particularly in the liver, heart, kidney and hair tissues. However, this effect was observed most often in animals fed both B{sub 12} and folate. Vitamin C appears to play a synergistic role with vitamin B{sub 12} and/or folate in the methylation of mercury.

Zorn, N.E.



Contribution of serine, folate and glycine metabolism to the ATP, NADPH and purine requirements of cancer cells  

PubMed Central

Recent observations on cancer cell metabolism indicate increased serine synthesis from glucose as a marker of poor prognosis. We have predicted that a fraction of the synthesized serine is routed to a pathway for ATP production. The pathway is composed by reactions from serine synthesis, one-carbon (folate) metabolism and the glycine cleavage system (SOG pathway). Here we show that the SOG pathway is upregulated at the level of gene expression in a subset of human tumors and that its level of expression correlates with gene signatures of cell proliferation and Myc target activation. We have also estimated the SOG pathway metabolic flux in the NCI60 tumor-derived cell lines, using previously reported exchange fluxes and a personalized model of cell metabolism. We find that the estimated rates of reactions in the SOG pathway are highly correlated with the proliferation rates of these cell lines. We also observe that the SOG pathway contributes significantly to the energy requirements of biosynthesis, to the NADPH requirement for fatty acid synthesis and to the synthesis of purines. Finally, when the PC-3 prostate cancer cell line is treated with the antifolate methotrexate, we observe a decrease in the ATP levels, AMP kinase activation and a decrease in ribonucleotides and fatty acids synthesized from [1,2-13C2]-D-glucose as the single tracer. Taken together our results indicate that the SOG pathway activity increases with the rate of cell proliferation and it contributes to the biosynthetic requirements of purines, ATP and NADPH of cancer cells. PMID:24157871

Tedeschi, P M; Markert, E K; Gounder, M; Lin, H; Dvorzhinski, D; Dolfi, S C; Chan, L L-Y; Qiu, J; DiPaola, R S; Hirshfield, K M; Boros, L G; Bertino, J R; Oltvai, Z N; Vazquez, A



Folate Intake, MTHFR C677T Polymorphism, Alcohol Consumption, and Risk for Sporadic Colorectal Adenoma (United States)  

Microsoft Academic Search

Objective: The purpose of this study was to investigate whether folate intake is associated with risk for incident sporadic colorectal adenoma, and whether the association differs according to methylenetetrahydrofolate reductase (MTHFR) genotypes or is modified by intakes of alcohol or other micronutrients in the folate metabolism pathway.

Sonia M. Boyapati; Roberd M. Bostick; Katherine A. McGlynn; Michael F. Fina; Walter M. Roufail; Kim R. Geisinger; James R. Hebert; Ann L. Coker; Michael Wargovich



Folate and arsenic metabolism: a double-blind, placebo-controlled folic acid-supplementation trial in Bangladesh13  

Microsoft Academic Search

Background: Populations in South and East Asia and many other regions of the world are chronically exposed to arsenic- contaminated drinking water. To various degrees, ingested inor- ganic arsenic (InAs) is methylated to monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) via folate-dependent one- carbon metabolism; impaired methylation is associated with ad- verse health outcomes. Consequently, folate nutritional status may influence

Mary V Gamble; Xinhua Liu; Habibul Ahsan; J Richard Pilsner; Vesna Ilievski; Vesna Slavkovich; Faruque Parvez; Yu Chen; Diane Levy; Pam Factor-Litvak; Joseph H Graziano


Mutation in Folate Metabolism Causes Epigenetic Instability and Transgenerational Effects On Development  

PubMed Central

SUMMARY The importance of maternal folate consumption for normal development is well established. Yet, the molecular mechanism linking folate metabolism to development remains poorly understood. The enzyme methionine synthase reductase (MTRR) is necessary for utilization of methyl groups from the folate cycle. We found that a hypomorphic mutation of the mouse Mtrr gene results in intrauterine growth restriction, developmental delay and congenital malformations including neural tube, heart and placental defects. Importantly, these defects were dependent upon the Mtrr genotypes of the maternal grandparents. Furthermore, we observed widespread epigenetic instability associated with altered gene expression in the placentas of wildtype grandprogeny of Mtrr-deficient maternal grandparents. Embryo transfer experiments revealed two epigenetic mechanisms of Mtrr deficiency in mice: adverse effects on their wildtype daughters’ uterine environment leading to growth defects in wildtype grandprogeny, and the appearance of congenital malformations independent of maternal environment that persist for five generations, likely through transgenerational epigenetic inheritance. PMID:24074862

Padmanabhan, Nisha; Jia, Dongxin; Geary-Joo, Colleen; Wu, Xuchu; Ferguson-Smith, Anne C.; Fung, Ernest; Bieda, Mark C.; Snyder, Floyd F.; Gravel, Roy A.; Cross, James C.; Watson, Erica D.



Serum Folate and Cobalamin Levels in Women Using Combined Contraceptive Vaginal Ring  

PubMed Central

Purpose: The aim of our study was to evaluate the effects of combined contraceptive vaginal rings on serum concentrations of folate and cobalamin in healthy users. Material and Methods: Case-control study on cobalamin and folate status of 45 healthy female nulligravidae using a combined contraceptive vaginal ring for >?3 months and 45 healthy controls. Factors interfering with vitamin metabolism were thoroughly controlled. Results: Cobalamin and folate levels did not differ between the groups. Vegetarian diet, smoking or obesity did not have a significant influence. Conclusions: The use of a combined contraceptive vaginal ring provides an appropriate hormonal contraception in women with pre-existing cobalamin deficiency or restrictive diet habit in order to avoid interferences between vitamin B12 metabolism and exogenously applied estrogens.

Bussen, S.; Bussen, D.



Folate Deficiency during Early-Mid Pregnancy Affects the Skeletal Muscle Transcriptome of Piglets from a Reciprocal Cross  

PubMed Central

Folate deficiency (FD) during pregnancy can cause fetal intrauterine growth restriction in pigs, of which the skeletal dysplasia is a major manifestation. Factors influencing muscle development are very important in the formation of porcine meat quality trait. However, the effect of folate deficiency on skeletal muscle development and its molecular mechanisms are unknown. The objective of this study is to determine the effect of maternal folate deficiency on the skeletal muscle transcriptome of piglets from a reciprocal cross, in which full-sibling Landrace (LR) and full-sibling Chinese local breed Laiwu (LW) pigs were used for reciprocal cross matings, and sows were fed either a folate deficient or a normal diet during early-mid gestation. In addition, the difference in the responsiveness of the piglets to folate deficiency during early-mid pregnancy between reciprocal cross groups was investigated. Longissimus dorsi (LD) muscle samples were collected from newborn piglets and a 4 × 44K Agilent porcine oligo microarray was used for transcriptome analysis of porcine LD muscle. The results showed that folate deficiency during early-mid pregnancy affected piglet body weight, LD muscle fiber number and content of intramuscular triglyceride. The microarray results indicated that 3154 genes were differentially expressed between folate deficient and normal piglets from the LR? × LW? cross, and 3885 differentially expressed genes (DEGs) in the ones from the LW? × LR? cross. From functional analyses, sow folate deficiency affected almost all biological processes in the progeny. Lipid metabolism-related genes and associated metabolic pathways were regulated extensively by folate deficiency, especially in LR? × LW? cross piglets. Most of the genes that are regulated by folate deficiency in the LD muscle of piglets were different between LR? × LW? and LW? × LR? crosses, suggesting some epigenetic effects of FD exist in genes underlying myogenesis and intramuscular fat deposition in piglets. PMID:24349320

Li, Yi; Zhang, Xu; Sun, Yanxiao; Feng, Qiang; Li, Guanglei; Wang, Meng; Cui, Xinxing; Kang, Li; Jiang, Yunliang



Review of the magnitude of folate and vitamin B12 deficiencies worldwide.  


Human deficiencies of folate and vitamin B12 result in adverse effects which may be of public health significance, but the magnitude of these deficiencies is unknown. Therefore, we examine the prevalence data currently available, assess global coverage of surveys, determine the frequency with which vitamin status assessment methods are used, and identify patterns of status related to geographical distribution and human development. Surveys were identified through PubMed and the Vitamin and Mineral Nutrition Information System at the World Health Organization (WHO). Since different thresholds were frequently used to define deficiency, measures of central tendency were used to compare blood vitamin concentrations among countries. The percentage of countries with at least one survey is highest in the WHO Regions of South-East Asia and Europe. Folate and vitamin B12 status were most frequently assessed in women of reproductive age (34 countries), and in all adults (27 countries), respectively. Folate status assessment surveys assessed plasma or serum concentrations (55%), erythrocyte folate concentrations (21%), or both (23%). Homocysteine was assessed in one-third of the surveys of folate and vitamin B12 status (31% and 34% respectively), while methylmalonic acid was assessed in fewer surveys of vitamin B12 status (13%). No relationship between vitamin concentrations and geographical distribution, level of development, or population groups could be identified, but nationally representative data were few. More representative data and more consistent use of thresholds to define deficiency are needed in order to assess whether folate and vitamin B12 deficiencies are a public health problem. PMID:18709880

McLean, Erin; de Benoist, Bruno; Allen, Lindsay H



Acculturation factors are associated with folate intakes among Mexican American women.  


Folic acid can prevent neural tube defects (NTD). Hispanic women have a higher prevalence of NTD than non-Hispanic white (NHW) women and consume less folic acid. Among Hispanics, acculturation has been associated with lower intakes of natural folate. It is unknown if this same relationship is seen for fortified foods. This article describes the associations of acculturation factors with usual folate intakes from foods and supplements and compares the proportion that meets recommended intakes of folic acid of US Mexican American (MA) women with those of NHW women. For US NHW and MA women aged 15-44 y (n = 3167), usual folate intakes (i.e., natural food folate, folic acid from food, total folic acid [fortified foods plus supplements], and total folate) were estimated using measurement error models from NHANES 2001-2008. Compared with NHW women, MA women did not differ in their intake of natural food folate or folic acid from food. Similarly, compared with NHW women (332 ± 17.3 ?g/d), the mean total usual folic acid intakes were lower among MA women who reported speaking Spanish (224 ± 24.9 ?g/d) but not for MA women who reported speaking English (283 ± 36.2 ?g/d). MA women were more likely than NHW women to consume a total folic acid intake <400 ?g/d. MA women with lower acculturation factors were the most likely to have an intake <400 ?g/d compared to NHW women. Public health efforts should focus on increasing total folic acid intake among MA women, emphasizing those with lower acculturation factors (e.g., MA women who report speaking Spanish). PMID:21865570

Hamner, Heather C; Cogswell, Mary E; Johnson, Mary Ann



Homocysteine Lowering by Folate-Rich Diet or Pharmacological Supplementations in Subjects with Moderate Hyperhomocysteinemia  

PubMed Central

Background/Objectives: To compare the efficacy of a diet rich in natural folate and of two different folic acid supplementation protocols in subjects with “moderate” hyperhomocysteinemia, also taking into account C677T polymorphism of 5,10-methylenetetrahydrofolate reductase (MTHFR) gene. Subjects/Methods: We performed a 13 week open, randomized, double blind clinical trial on 149 free living persons with mild hyperhomocyteinemia, with daily 200 ?g from a natural folate-rich diet, 200 ?g [6S]5-methyltetrahydrofolate (5-MTHF), 200 ?g folic acid or placebo. Participants were stratified according to their MTHFR genotype. Results: Homocysteine (Hcy) levels were reduced after folate enriched diet, 5-MTHF or folic acid supplementation respectively by 20.1% (p < 0.002), 19.4% (p < 0.001) and 21.9% (p < 0.001), as compared to baseline levels and significantly as compared to placebo (p < 0.001, p < 0.002 and p < 0.001, respectively for enriched diet, 5-MTHF and folic acid). After this enriched diet and the folic acid supplementation, Hcy in both genotype groups decreased approximately to the same level, with higher percentage decreases observed for the TT group because of their higher pre-treatment value. Similar results were not seen by genotype for 5-MTHF. A significant increase in RBC folate concentration was observed after folic acid and natural folate-rich food supplementations, as compared to placebo. Conclusions: Supplementation with natural folate-rich foods, folic acid and 5-MTHF reached a similar reduction in Hcy concentrations. PMID:23698160

Zappacosta, Bruno; Mastroiacovo, Pierpaolo; Persichilli, Silvia; Pounis, George; Ruggeri, Stefania; Minucci, Angelo; Carnovale, Emilia; Andria, Generoso; Ricci, Roberta; Scala, Iris; Genovese, Orazio; Turrini, Aida; Mistura, Lorenza; Giardina, Bruno; Iacoviello, Licia



Phospholipid biosynthesis in mammalian cells.  


Identification of the genes and gene products involved in the biosynthesis of phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine has lagged behind that in many other fields because of difficulties encountered in purifying the respective proteins. Nevertheless, most of these genes have now been identified. In this review article, we have highlighted important new findings on the individual enzymes and the corresponding genes of phosphatidylcholine synthesis via its two major biosynthetic pathways: the CDP-choline pathway and the methylation pathway. We also review recent studies on phosphatidylethanolamine biosynthesis by two pathways: the CDP-ethanolamine pathway, which is active in the endoplasmic reticulum, and the phosphatidylserine decarboxylase pathway, which operates in mitochondria. Finally, the two base-exchange enzymes, phosphatidylserine synthase-1 and phosphatidylserine synthase-2, that synthesize phosphatidylserine in mammalian cells are also discussed. PMID:15052332

Vance, Jean E; Vance, Dennis E



Folate Levels and Polymorphisms in the Genes MTHFR, MTR, and TS in Colorectal Cancer  

PubMed Central

AIM The aim of the study was to explore and describe the effect of polymorphisms in folate-associated genes regarding the levels of different folate forms and their distribution in tumors and mucosa in patients with colorectal cancer. MATERIALS AND METHODS Tumor and mucosa tissues from 53 patients with colorectal cancer were analyzed. The concentrations of tetrahydrofolate (THF), 5-methylTHF, and 5,10-methyleneTHF were measured by liquid chromatography—mass spectrometry. Genotyping of polymorphisms in the folate-associated genes methylenetetrahydrofolate reductase (MTHFR, C677T), methionine synthase (MTR, A2756G), and thymidylate synthase (TS, 5?-TSER 28 bp tandem repeat and 3?-TSUTR 6 bp deletion/insertion), were done by real-time polymerase chain reaction. Folate levels and distributions were determined in the total patient cohort and after subgrouping by genotypes. RESULTS The total folate level, as well as the THF and 5,10-methyleneTHF levels, were significantly higher in the tumor compared with mucosa tissue (P = 0.030, 0.031, and 0.015, respectively). The individual variation in folate levels in both tumor and mucosa were larger than the variation found when the patients were subgrouped by the gene polymorphisms. No significant differences in the mean concentration of any folate in the mucosa or tumor tissue were found in relation to the analyzed polymorphisms. The percentage level of 5,10-methyleneTHF in tumors was highest in patients with the MTHFR 677 CC genotype, and lowest in patients with the TT genotype (P = 0.033). A significantly lower percentage level of the 5,10-methyleneTHF level was found in tumors of patients with the 5?-TSER 3R/3R genotype (P = 0.0031). CONCLUSION A significant difference was found between the percentage level of 5,10-methyleneTHF in tumor tissues in relation to the MTHFR C677T and 5?-TSER 28 bp repeat polymorphisms. However, no differences were found in the actual tissue folate levels, or in their distribution, in relation to the polymorphisms in the MTHFR, MTR, or TS genes. These findings could be of importance for further research in the field by explaining some of the difficulties of obtaining reproducible and uniform results when using a few selected polymorphisms as predictive markers. PMID:24596472

Taflin, Helena; Wettergren, Yvonne; Odin, Elisabeth; Carlsson, Goran; Derwinger, Kristoffer



Targeting Diamond Nanoparticles into Folate-Receptor Expressing HeLa Cells  

NASA Astrophysics Data System (ADS)

We have studied binding of synthesized folic acid-diamond nanoparticle conjugates to proliferatively active HeLa cells. In order to determine the binding of the complex to the cells, we used spectral luminescence methods and microscopy, which let us visualize localization of the conjugate in the cellular system in vitro. We show that the conjugate under study binds to folate-receptor expressing HeLa cells. We have established a determining role for the folate receptor in binding of the conjugate to the cells. Our studies suggest that is it possible to use the conjugate as a targeted nanoplatform for targeted delivery of diagnostic and therapeutic agents to tumor cells.

Lapina, V. A.; Vorobey, A. V.; Pavich, T. A.; Opitz, J.



?-alanine biosynthesis in Methanocaldococcus jannaschii.  


One efficient approach to assigning function to unannotated genes is to establish the enzymes that are missing in known biosynthetic pathways. One group of such pathways is those involved in coenzyme biosynthesis. In the case of the methanogenic archaeon Methanocaldococcus jannaschii as well as most methanogens, none of the expected enzymes for the biosynthesis of the ?-alanine and pantoic acid moieties required for coenzyme A are annotated. To identify the gene(s) for ?-alanine biosynthesis, we have established the pathway for the formation of ?-alanine in this organism after experimentally eliminating other known and proposed pathways to ?-alanine from malonate semialdehyde, l-alanine, spermine, dihydrouracil, and acryloyl-coenzyme A (CoA). Our data showed that the decarboxylation of aspartate was the only source of ?-alanine in cell extracts of M. jannaschii. Unlike other prokaryotes where the enzyme producing ?-alanine from l-aspartate is a pyruvoyl-containing l-aspartate decarboxylase (PanD), the enzyme in M. jannaschii is a pyridoxal phosphate (PLP)-dependent l-aspartate decarboxylase encoded by MJ0050, the same enzyme that was found to decarboxylate tyrosine for methanofuran biosynthesis. A Km of ?0.80 mM for l-aspartate with a specific activity of 0.09 ?mol min(-1) mg(-1) at 70°C for the decarboxylation of l-aspartate was measured for the recombinant enzyme. The MJ0050 gene was also demonstrated to complement the Escherichia coli panD deletion mutant cells, in which panD encoding aspartate decarboxylase in E. coli had been knocked out, thus confirming the function of this gene in vivo. PMID:24891443

Wang, Yu; Xu, Huimin; White, Robert H



Biosynthesis of Ochratoxin A1  

PubMed Central

Biosynthesis of ochratoxin A by Aspergillus ochraceus Wilh. was investigated by radiolabeling experiments in which phenylalanine-1-14C and sodium acetate-2-14C were supplied to the fungus in sucrose-yeast extract medium. Results showed that phenylalanine was incorporated unaltered into the phenylalanine moiety of ochratoxin A, whereas the isocoumarin moiety of ochratoxin A was mostly derived via acetate condensation. PMID:5369298

Searcy, J. W.; Davis, N. D.; Diener, U. L.



Pullulan: biosynthesis, production, and applications  

Microsoft Academic Search

Pullulan is a linear glucosic polysaccharide produced by the polymorphic fungus Aureobasidium pullulans, which has long been applied for various applications from food additives to environmental remediation agents. This review\\u000a article presents an overview of pullulan’s chemistry, biosynthesis, applications, state-of-the-art advances in the enhancement\\u000a of pullulan production through the investigations of enzyme regulations, molecular properties, cultivation parameters, and\\u000a bioreactor design.

Kuan-Chen Cheng; Ali Demirci; Jeffrey M. Catchmark


Taxol Biosynthesis and Molecular Genetics  

Microsoft Academic Search

Biosynthesis of the anticancer drug Taxol in Taxus (yew) species involves 19 steps from the universal diterpenoid progenitor geranylgeranyl diphosphate derived by the plastidial methyl erythritol phosphate pathway for isoprenoid precursor supply. Following the committed cyclization to the taxane skeleton, eight cytochrome P450-mediated oxygenations, three CoA-dependent acyl\\/aroyl transfers, an oxidation at C9, and oxetane (D-ring) formation yield the intermediate baccatin

Rodney Croteau; Raymond E. B. Ketchum; Robert M. Long; Rüdiger Kaspera; Mark R. Wildung



Starch biosynthesis in cereal endosperm.  


Stored starch generally consists of two d-glucose homopolymers, the linear polymer amylose and a highly branched glucan amylopectin that connects linear chains. Amylopectin structurally contributes to the crystalline organization of the starch granule in cereals. In the endosperm, amylopectin biosynthesis requires the proper execution of a coordinated series of enzymatic reactions involving ADP glucose pyrophosphorylase (AGPase), soluble starch synthase (SS), starch branching enzyme (BE), and starch debranching enzyme (DBE), whereas amylose is synthesized by AGPase and granule-bound starch synthase (GBSS). It is highly possible that plastidial starch phosphorylase (Pho1) plays an important role in the formation of primers for starch biosynthesis in the endosperm. Recent advances in our understanding of the functions of individual enzyme isoforms have provided new insights into how linear polymer chains and branch linkages are synthesized in cereals. In particular, genetic analyses of a suite of mutants have formed the basis of a new model outlining the role of various enzyme isoforms in cereal starch production. In our current review, we summarize the recent research findings related to starch biosynthesis in cereal endosperm, with a particular focus on rice. PMID:20400324

Jeon, Jong-Seong; Ryoo, Nayeon; Hahn, Tae-Ryong; Walia, Harkamal; Nakamura, Yasunori



The purification, crystallization and preliminary structural characterization of human MAWDBP, a member of the phenazine biosynthesis-like protein family  

PubMed Central

MAWDBP is the only representative of the phenazine biosynthesis-like protein family in the human genome. Its expression is elevated in several disease processes, including insulin resistance, folate deficiency and hypotension, and it may also be involved in carcinogenesis. The exact molecular function of MAWDBP is unknown. Native and seleno-l-methionine-labelled MAWDBP were expressed in Escherichia coli and crystallized at room temperature from precipitants containing 10?mM KF, 14%(w/v) PEG 3350 and 0.1?M sodium citrate pH 5.4. Crystals belong to space group H32, with unit-cell parameters a = b = 187, c = 241?Å, indicative of three to five monomers per asymmetric unit. Crystals were cryoprotected with 15%(v/v) glycerol and data have been collected to 2.7?Å resolution. PMID:16754977

Herde, Petra; Blankenfeldt, Wulf



Dual Methylation Pathways in Lignin Biosynthesis  

Microsoft Academic Search

Caffeoyl-coenzyme A (CoA) O -methyltransferase (CCoAOMT) has been proposed to be involved in an alternative meth- ylation pathway of lignin biosynthesis. However, no direct evidence has been available to confirm that CCoAOMT is es- sential for lignin biosynthesis. To understand further the methylation steps in lignin biosynthesis, we used an antisense approach to alter O -methyltransferase ( OMT ) gene

Ruiqin Zhong; W. Herbert Morrison; Jonathan Negrel; Zheng-Hua Ye



Determination of folate/folic acid level in milk by microbiological assay, immuno assay and high performance liquid chromatography.  


A concurrent determination of folate versus folic acid in milk by microbiological assay (MA) with Lactobacillus rhamnosus as the assay organism, Enzyme Linked Immuno Sorbent Assay (ELISA) by competitive binding rapid ELISA kit (RIDASCREEN®) and high-pressure-liquid chromatography (HPLC) was done for detection of the folate form and its level. MA gave total folate content as Lb. rhamnosus showed similar response to most folate isomers formed by the tri-enzyme treatment in comparison with the other two methods which specifically estimated the folic acid. In case of ELISA, specificity was apparently limited to folic acid and dihydro folic acid and thereby showed a lower response for other folate derivatives. Estimation by HPLC with UV detector was highly specific and hence only folic acid could be detected without any cross reactivity. Among the different methods HPLC was observed to be the most sensitive method for determination of folic acid and hence can efficiently determine the folic acid fortification level while MA remained highly efficient, sensitive and reproducible method for estimation of total folate indicating its potential use for dietary folate estimation. PMID:23506679

Iyer, Ramya; Tomar, Sudhir Kumar



The targeted behavior of folate-decorated N-succinyl-N'-octyl chitosan evaluated by NIR system in mouse model  

NASA Astrophysics Data System (ADS)

The development of more selective delivery systems for cancer diagnosis and chemotherapy is one of the most important goals of current anticancer research. The purpose of this study is to construct and evaluate the folate-decorated, self-assembled nanoparticles as candidates to deliver near infrared fluorescent dyes into tumors and to investigate the mechanisms underlying the tumor targeting with folate-decorated, self-assembled nanoparticles. Folate-decorated N-succinyl-N'-octyl chitosan (folate-SOC) were synthesized. The chemical modification chitosan could self-assemble into stable micelles in aqueous medium. Micelle size determined by size analysis was around 140 nm in a phosphate-buffered saline (PBS, PH 7.4). Folate-SOC could maintain their structure for up to 15 days in PBS. Near infrared dye ICG-Der-01 as a mode drug was loaded in the micelles, and the entrapment efficiency (EE) and drug loading (DL) were investigated. The targeted behavior of folate-SOC was evaluated by near-infrared fluorescence imaging in vivo on different groups of denuded mice, with A549 or Bel-7402 tumors. The optical imaging results indicated that folated-decorated SOC showed an excellent tumor specificity in Bel-7402 tumor-bearing mice, and weak tumor specificity in A549 tumor bearing mice. We believe that this work can provide insight for the engineering of nanoparticles and be extended to cancer therapy and diagnosis so as to deliver multiple therapeutic agents and imaging probes at high local concentrations.

Zhu, Hongyan; Deng, Dawei; Chen, Haiyan; Qian, Zhiyu; Gu, Yueqing



Microfluidic Synthesis of PEG- and Folate-Conjugated Liposomes for One-Step Formation of Targeted Stealth Nanocarriers  

PubMed Central

Purpose A microfluidic hydrodynamic flow focusing technique enabling the formation of small and nearly monodisperse liposomes is investigated for continuous-flow synthesis of poly(ethylene glycol) (PEG)-modified and PEG-folate-functionalized liposomes for targeted drug delivery. Methods Controlled laminar flow in thermoplastic microfluidic devices facilitated liposome self-assembly from initial lipid compositions including lipid/cholesterol mixtures containing PEG-lipid and folate-PEG-lipid conjugates. The relationships between flow conditions, lipid composition, and liposome size were evaluated, and the impact of these parameters on PEG and folate incorporation were determined through a combination of UV-vis absorbance measurements and characterization of liposome zeta potential. Results Both PEG and folate were successfully incorporated into microfluidic-synthesized liposomes over the full range of liposome sizes studied. The efficiency of PEG-lipid incorporation was found to be inversely correlated with liposome diameter. Folate-lipid was also effectively integrated into liposomes at various flow conditions. Conclusions Liposomes incorporating relatively large PEG-modified and folate-PEG-modified lipids were successfully synthesized using the microfluidic flow focusing platform, providing a simple, low cost, rapid method for preparing functionalized liposomes. Relationships between preparation conditions and PEG or folate-PEG functionalization have been elucidated, providing insight into the process and defining paths for optimization of the microfluidic method toward the formation of functionalized liposomes for pharmaceutical applications. PMID:23386106

Hood, Renee R.; Shao, Chenren; Omiatek, Donna M.; Vreeland, Wyatt N.; DeVoe, Don L.



Folate-functionalized dendrimers for targeting Chlamydia-infected tissues in a mouse model of reactive arthritis.  


Chlamydia trachomatis is an intracellular human pathogen that causes a sexually transmitted disease which may result in an inflammatory arthritis designated Chlamydia-induced reactive arthritis (ReA). The arthritis develops after dissemination of infected cells from the initial site of chlamydial infection. During Chlamydia-associated ReA, the organism may enter into a persistent infection state making treatment with antibiotics a challenge. We hypothesize that folate receptors (FR), which are overexpressed in Chlamydia-infected cells, and the associated inflammation would allow folate-targeted nanodevices to better treat infections. To investigate this, we developed a folate-PAMAM dendrimer-Cy5.5 conjugate (D-FA-Cy5.5), where Cy5.5 is used as the near-IR imaging agent. Uptake of D-FA-Cy5.5 upon systemic administration was assessed and compared to non-folate conjugated controls (D-Cy5.5), using a mouse model of Chlamydia-induced ReA, and near-IR imaging. Our results suggested that there was a higher concentration of folate-based nanodevice in sites of infection and inflammation compared to that of the control nanodevice. The folate-conjugated nanodevices localized to infected paws and genital tracts (major sites of inflammation and infection) at 3-4 fold higher concentrations than were dendrimer alone, suggesting that the overexpression of folate receptors in infected and inflamed tissues enables higher dendrimer uptake. There was an increase in uptake into thymus, spleen, and lung, but no significant differences in the uptake of the folate nanodevices in other organs including kidney and heart, indicating the 'relative specificity' of the D-FA-Cy5.5 conjugate nanodevices. These results suggest that folate targeting dendrimers are able to deliver drugs to attenuate infection and associated inflammation in Chlamydia-induced ReA. PMID:24607214

Benchaala, Ilyes; Mishra, Manoj K; Wykes, Susan M; Hali, Mirabela; Kannan, Rangaramanujam M; Whittum-Hudson, Judith A



Folate deficiency exacerbates apoptosis by inducing hypomethylation and resultant overexpression of DR4 together with altering DNMTs in Alzheimer's disease  

PubMed Central

This study was to evaluate patterns of gene expression and promoter methylation of DR4 from peripheral circulating blood lymphocytes of AD patients and folate-deficiency medium cultured neuroblast cells, and also expression levels of DNMT1, DNMT3a, and MECP2. Blood samples of 25 pairs of AD patients and age- and sex-matched controls were collected. SH-SY5Y cells were cultured with folate-deficiency medium. Bisulfite cloning coupled with sequencing was employed to analyze methylation levels of DR4 gene promoters, and quantitative real time PCR (qRT-PCR) was used to detect gene expression levels of DR4, and also DNA methyltransferase 1 (DNMT1), DNA methyltransferase 3a (DNMT3a) and methyl CpG binding protein 2 (MECP2). Folate concentration was calculated in serum of blood samples. 3-(4,5-di-methylthiazol-2-yl)-2,5-diphenyl tetrazolium (MTT) assay was used to analyze cell viability. The results showed that, the promoter of DR4 was hypomethylated in AD patients and cells cultured in folate-deficiency medium and had site-specific changes (P < 0.05), and these sites were mostly at or nearby some key transcription factor binding sites. Accordance with the hypomethylation, increased expression level of DR4 was observed (P < 0.05). DNMT1 and DNMT3a mRNA level were elevated (P < 0.05) in AD patients and folate deficient medium cultured cells compared with controls (P < 0.05), together with lower folate concentration in AD. MTT assay showed that folate deficiency inhibited cell growth. In summary, folate deficiency can induce apoptosis by increasing DR4 expression with DNA promoter hypomethylation in AD, together with upregulating DNMTs expression, which may be associated with folate deficiency-induced DNA damage. PMID:25232375

Wang, Yun; Xu, Shunliang; Cao, Yanjun; Xie, Zhaohong; Lai, Chao; Ji, Xiaowei; Bi, Jianzhong



The Obligatory Intestinal Folate Transporter PCFT (SLC46A1) Is Regulated by Nuclear Respiratory Factor 1  

PubMed Central

Folates are essential vitamins that play a key role as one-carbon donors in a spectrum of biosynthetic pathways including RNA and DNA synthesis. The proton-coupled folate transporter (PCFT/SLC46A1) mediates obligatory intestinal folate absorption. Loss-of-function mutations in PCFT result in hereditary folate malabsorption, an autosomal recessive disorder characterized by very low folate levels in the blood and cerebrospinal fluid. Hereditary folate malabsorption manifests within the first months after birth with anemia, immune deficiency, and neurological deficits. Here we studied the role of inducible trans-activators of PCFT gene expression. Bioinformatics identified three putative nuclear respiratory factor 1 (NRF-1) binding sites in the minimal promoter. The following evidence establish that PCFT is an NRF-1-responsive gene; electrophoretic mobility shift assay showed NRF-1 binding to native but not mutant NRF-1 sites, whereas antibody-mediated supershift analysis and chromatin immunoprecipitation revealed NRF-1 binding to its consensus sites within the PCFT promoter. Moreover, mutational inactivation of individual or all NRF-1 binding sites resulted in 40–60% decrease in luciferase reporter activity. Consistently, overexpression of NRF-1 or a constitutively active NRF-1 VP-16 construct resulted in increased reporter activity and PCFT mRNA levels. Conversely, introduction of a dominant-negative NRF-1 construct markedly repressed reporter activity and PCFT mRNA levels; likewise, introduction of NRF-1 siRNA duplexes to cells resulted in decreased PCFT transcript levels. Moreover, NRF-1 silencing down-regulated genes encoding for key folate transporters and enzymes in folate metabolism. These novel findings identify NRF-1 as a major inducible transcriptional regulator of PCFT gene expression. The implications of this linkage between folate transport and metabolism with mitochondria biogenesis and respiration are discussed. PMID:20724482

Gonen, Nitzan; Assaraf, Yehuda G.



Folate intake and depressive symptoms in Japanese workers considering SES and job stress factors: J-HOPE study  

PubMed Central

Background Recently socioeconomic status (SES) and job stress index received more attention to affect mental health. Folate intake has been implicated to have negative association with depression. However, few studies were published for the evidence association together with the consideration of SES and job stress factors. The current study is a part of the Japanese study of Health, Occupation and Psychosocial factors related Equity (J-HOPE study) that focused on the association of social stratification and health and our objective was to clarify the association between folate intake and depressive symptoms in Japanese general workers. Methods Subjects were 2266 workers in a Japanese nationwide company. SES and job stress factors were assessed by self-administered questionnaire. Folate intake was estimated by a validated, brief, self-administered diet history questionnaire. Depressive symptoms were measured by Kessler’s?K6 questionnaire. “Individuals with depressive symptoms” was defined as K6?9 (in K6 score of 0–24 scoring system). Multiple logistic regression and linear regression model were used to evaluate the association between folate and depressive symptoms. Results Several SES factors (proportion of management positions, years of continuous employment, and annual household income) and folate intake were found to be significantly lower in the subjects with depressive symptom (SES factors: p?folate intake: P?=?0.001). There was an inverse, independent linear association between K6 score and folate intake after adjusting for age, sex, job stress scores (job strains, worksite supports), and SES factors (p?=?0.010). The impact of folate intake on the prevalence of depressive symptom by a multiple logistic model was (ORs[95% CI]: 0.813 [0.664-0.994]; P =0.044). Conclusions Our cross-sectional study suggested an inverse, independent relation of energy-adjusted folate intake with depression score and prevalence of depressive symptoms in Japanese workers, together with the consideration of SES and job stress factors. PMID:22521003



Folate Receptor-? Is a Cofactor for Cellular Entry by Marburg and Ebola Viruses  

Microsoft Academic Search

Human infections by Marburg (MBG) and Ebola (EBO) viruses result in lethal hemorrhagic fever. To identify cellular entry factors employed by MBG virus, noninfectible cells transduced with an expression library were challenged with a selectable pseudotype virus packaged by MBG glycoproteins (GP). A cDNA encoding the folate receptor-? (FR-?) was recovered from cells exhibiting reconstitution of viral entry. A FR-?

Stephen Y. Chan; Cyril J. Empig; Frank J. Welte; Roberto F. Speck; Alan Schmaljohn; Jason F. Kreisberg; Mark A. Goldsmith



Association of dietary intake of folate and MTHFR genotype with breast cancer risk.  


We conducted a hospital-based case-control study to investigate the associations of dietary intake of folate and MTHFR C677T and A1298C polymorphisms with breast cancer in a Chinese population. A 1:1-matched case-control study was conducted. Two hundred and thirty patients who were newly diagnosed and histologically confirmed breast cancer and 230 controls were enrolled from Xinxiang Central Hospital. Folate intake was calculated by standard portion size and relative size for each food item in the questionnaire. Genotyping of MTHFR C677T and A1298C was performed by PCR-RFLP. MTHFR 677TT (OR = 2.26, 95%CI = 1.09-4.87, P = 0.02) and T allele (OR = 1.40, 95%CI = 1.03-1.90, P = 0.03) had an increased risk of laryngeal cancer when compared with the CC genotype. We found any interaction between MTHFR C677T and folate intake (P for interaction = 0.02). In conclusion, our study demonstrated that MTHFR C677T polymorphism and folate are associated with risk of breast cancer. PMID:25078601

Wang, Z G; Cui, W; Yang, L F; Zhu, Y Q; Wei, W H



Ionic charge, hydrophobicity and tryptophan fluorescence of the folate binding protein isolated from cow's milk.  


A high-affinity folate binding protein was isolated and purified from cow's milk by a combination of cation exchange chromatography and methotrexate affinity chromatography. Chromatofocusing studies revealed that the protein possessed isoelectric points in the pH-interval 8-7. Polymers of the protein prevailing at pH values close to the isoelectric points seemed to be more hydrophobic than monomers present at pH 5.0 as evidenced by hydrophobic interaction chromatography and turbidity (absorbance at 340 nm) in aqueous buffer solutions (pH 5-8). Ligand binding seemed to induce a conformation change that decreased the hydrophobicity of the protein. In addition, Ligand binding quenched the tryptophan fluorescence of folate binding protein suggesting that tryptophan is present at the binding site and/or ligand binding induces a conformation change that affects tryptophan environment in the protein. There was a noticeable discordance between the ability of individual folate analogues to compete with folate for binding and the quenching effect. PMID:11892997

Holm, J; Hansen, S I; Høier-Madsen, M



Author's personal copy Site-specific folate conjugation to a cytotoxic protein  

E-print Network

-produced on the surface of many types of cancer cells, such as those derived from ovarian, endome- trial, and brain: Bioconjugation Cancer Cytotoxin Folic acid Ribonuclease Ribonuclease inhibitor a b s t r a c t Conjugation folate moiety does not decrease enzymatic activity, enables RI-evasion, and endows toxicity for cancer

Raines, Ronald T.


Adding zinc to prenatal iron and folate tablets improves fetal neurobehavioral development  

Microsoft Academic Search

Objective: Our objective was to examine whether improvement in maternal zinc status during pregnancy is positively associated with fetal neurobehavioral development in a Peruvian population. Study Design: We electronically monitored, at 32 and 36 weeks’ gestation, 55 fetuses whose mothers were randomly assigned to receive, during pregnancy, a daily supplement containing 60 mg iron and 250 ?g folate, with or

Mario Merialdi; Laura E. Caulfield; Nelly Zavaleta; Alberto Figueroa; Janet A. DiPietro



Mammalian mitochondrial and cytosolic folylpolyglutamate synthetase maintain the subcellular compartmentalization of folates.  


Folylpoly-?-glutamate synthetase (FPGS) catalyze the addition of multiple glutamates to tetrahydrofolate derivatives. Two mRNAs for the fpgs gene direct isoforms of FPGS to the cytosol and to mitochondria in mouse and human tissues. We sought to clarify the functions of these two compartmentalized isoforms. Stable cell lines were created that express cDNAs for the mitochondrial and cytosolic isoforms of human FPGS under control of a doxycycline-inducible promoter in the AUXB1 cell line. AUXB1 are devoid of endogenous FPGS activity due to a premature translational stop at codon 432 in the fpgs gene. Loss of folates was not measurable from these doxycycline-induced cells or from parental CHO cells over the course of three CHO cell generations. Likewise, there was no detectable transfer of folate polyglutamates either from the cytosol to mitochondria, or from mitochondria to the cytosol. The cell line expressing cytosolic FPGS required exogenous glycine but not thymidine or purine, whereas cells expressing the mitochondrial isoform required exogenous thymidine and purine but not glycine for optimal growth and survival. We concluded that mitochondrial FPGS is required because folate polyglutamates are not substrates for transport across the mitochondrial membrane in either direction and that polyglutamation not only traps folates in the cytosol, but also in the mitochondrial matrix. PMID:25164808

Lawrence, Scott A; Titus, Steven A; Ferguson, Jennifer; Heineman, Amy L; Taylor, Shirley M; Moran, Richard G



Comparative genomics of bacterial and plant folate synthesis and salvage: predictions and validations  

PubMed Central

Background Folate synthesis and salvage pathways are relatively well known from classical biochemistry and genetics but they have not been subjected to comparative genomic analysis. The availability of genome sequences from hundreds of diverse bacteria, and from Arabidopsis thaliana, enabled such an analysis using the SEED database and its tools. This study reports the results of the analysis and integrates them with new and existing experimental data. Results Based on sequence similarity and the clustering, fusion, and phylogenetic distribution of genes, several functional predictions emerged from this analysis. For bacteria, these included the existence of novel GTP cyclohydrolase I and folylpolyglutamate synthase gene families, and of a trifunctional p-aminobenzoate synthesis gene. For plants and bacteria, the predictions comprised the identities of a 'missing' folate synthesis gene (folQ) and of a folate transporter, and the absence from plants of a folate salvage enzyme. Genetic and biochemical tests bore out these predictions. Conclusion For bacteria, these results demonstrate that much can be learnt from comparative genomics, even for well-explored primary metabolic pathways. For plants, the findings particularly illustrate the potential for rapid functional assignment of unknown genes that have prokaryotic homologs, by analyzing which genes are associated with the latter. More generally, our data indicate how combined genomic analysis of both plants and prokaryotes can be more powerful than isolated examination of either group alone. PMID:17645794

de Crecy-Lagard, Valerie; El Yacoubi, Basma; de la Garza, Rocio Diaz; Noiriel, Alexandre; Hanson, Andrew D



Smith, Higgin, and Raines Supplementary Data Site-specific folate conjugation to a cytotoxic protein  

E-print Network

DNA Synthesis S4 References and Notes S5 1 H NMR Spectrum of Folate Analogue 1 #12;Smith, Higgin and 6-TAMRA is a 3# 6-carboxytetramethylrhodamine group), was from Integrated DNA Technologies to a thick dark viscous liquid that was dripped into benzene (150 mL). The precipitate was filtered, washed

Raines, Ronald T.


Folate-functionalized polymeric micelles for tumor targeted delivery of a potent multidrug-resistance  

E-print Network

Folate-functionalized polymeric micelles for tumor targeted delivery of a potent multidrug, polymeric micelles encoded with folic acid on the micelle surface were prepared with the encapsulation Mater Res 86A: 48­60, 2008 Key words: multidrug resistance; polymeric micelles; poly (ethylene glycol

Gao, Jinming


Blood folate is associated with asymptomatic or partially symptomatic Alzheimer's disease in the Nun study.  


Asymptomatic and partially symptomatic Alzheimer's disease (APSYMAD) are a series of cognitive states wherein subjects have substantial Alzheimer's disease (AD) pathology (classification B or C by the Consortium to Establish a Registry for AD criteria), but have normal or only partially impaired cognitive function; all of these subjects are non-demented. These cognitive states may arise from the prevention or delay of clinical symptom expression by exposure to certain nutritional factors. This study examined blood levels of folate and antioxidants (i.e., carotenoids) in relation to APSYMAD, nested in the Nun study, a longitudinal study of aging and AD. Sixty elderly female subjects, who had AD on the basis of neuropathology exams, were included. Following adjustment for APOE4 status, education level, and age at blood draw, subjects with the highest blood folate levels had a higher likelihood of being in the APSYMAD group as compared to the demented (AD) group (odds ratio = 1.09, 95% CI = 1.00-1.18. p < 0.06). This association was not significantly influenced by additional adjustment for blood concentrations of carotenoids. Restriction of the population to subjects with near normal cognition on the cognitive state score (score = 1-3) indicated an elevated association with blood folate (odds ratio = 1.12, 95% CI = 1.01-1.25, p < 0.04). Blood carotenoids were not associated with APSYMAD. Thus, folate status may influence the expression of clinical symptoms of AD disease and aid in the delay or prevention of dementia. PMID:22064069

Wang, Huifen; Odegaard, Andrew; Thyagarajan, Bharat; Hayes, Jennifer; Cruz, Karen Santa; Derosiers, Mark F; Tyas, Suzanne L; Gross, Myron D



21 CFR 101.79 - Health claims: Folate and neural tube defects.  

Code of Federal Regulations, 2013 CFR

...mcg of folic acid, the Food and Drug Administration...a personal or family history of a pregnancy affected...shall not be made on foods that contain more than...amount of folate in the food. This information...those with a personal history of a neural...



21 CFR 101.79 - Health claims: Folate and neural tube defects.  

Code of Federal Regulations, 2012 CFR

...mcg of folic acid, the Food and Drug Administration...a personal or family history of a pregnancy affected...shall not be made on foods that contain more than...amount of folate in the food. This information...those with a personal history of a neural...



21 CFR 101.79 - Health claims: Folate and neural tube defects.  

Code of Federal Regulations, 2011 CFR

...mcg of folic acid, the Food and Drug Administration...a personal or family history of a pregnancy affected...shall not be made on foods that contain more than...amount of folate in the food. This information...those with a personal history of a neural...



Hyperhomocysteinemia in chronic alcoholism: correlation with folate, vitamin Bi 2, and vitamin B6 status13  

Microsoft Academic Search

Serum homocysteine concentrations have been shown to be a sensitive functional indicator of intracellular folate, vitamin B-12, and vitamin B-6 status. Chronic alcoholism is known to interfere with one-carbon metabolism, for which the above vitamins serve as coenzymes. In the present study, these vitamins were assessed in 32 chronic alcoholics and 3 1 healthy volunteers by measuring blood vitamin concentrations

MarIlia L Cravo; Lulsa M Gloria; Jacob Seihub; Marie R Nadeau; Manuela P Resende; C Nobre Leit; F Costa Mira


Brief Report: Autistic Symptoms, Developmental Regression, Mental Retardation, Epilepsy, and Dyskinesias in CNS Folate Deficiency  

ERIC Educational Resources Information Center

We studied seven children with CNS folate deficiency (CFD). All cases exhibited psychomotor retardation, regression, cognitive delay, and dyskinesia; six had seizures; four demonstrated neurological abnormalities in the neonatal period. Two subjects had profound neurological abnormalities that precluded formal behavioral testing. Five subjects…

Moretti, Paolo; Peters, Sarika U.; del Gaudio, Daniela; Sahoo, Trilochan; Hyland, Keith; Bottiglieri, Teodoro; Hopkin, Robert J.; Peach, Elizabeth; Min, Sang Hee; Goldman, David; Roa, Benjamin; Bacino, Carlos A.; Scaglia, Fernando




EPA Science Inventory

Effects of Dietary Folate on Arsenic-induced Gene Expression in Mice Arsenic, a drinking water contaminant, is a known carcinogen. Human exposure to inorganic arsenic has been linked to tumors of skin, bladder, lung, and to a lesser extent, kidney and liver. Dietary fola...


Tetrahydrobiopterin biosynthesis, regeneration and functions.  

PubMed Central

Tetrahydrobiopterin (BH(4)) cofactor is essential for various processes, and is present in probably every cell or tissue of higher organisms. BH(4) is required for various enzyme activities, and for less defined functions at the cellular level. The pathway for the de novo biosynthesis of BH(4) from GTP involves GTP cyclohydrolase I, 6-pyruvoyl-tetrahydropterin synthase and sepiapterin reductase. Cofactor regeneration requires pterin-4a-carbinolamine dehydratase and dihydropteridine reductase. Based on gene cloning, recombinant expression, mutagenesis studies, structural analysis of crystals and NMR studies, reaction mechanisms for the biosynthetic and recycling enzymes were proposed. With regard to the regulation of cofactor biosynthesis, the major controlling point is GTP cyclohydrolase I, the expression of which may be under the control of cytokine induction. In the liver at least, activity is inhibited by BH(4), but stimulated by phenylalanine through the GTP cyclohydrolase I feedback regulatory protein. The enzymes that depend on BH(4) are the phenylalanine, tyrosine and tryptophan hydroxylases, the latter two being the rate-limiting enzymes for catecholamine and 5-hydroxytryptamine (serotonin) biosynthesis, all NO synthase isoforms and the glyceryl-ether mono-oxygenase. On a cellular level, BH(4) has been found to be a growth or proliferation factor for Crithidia fasciculata, haemopoietic cells and various mammalian cell lines. In the nervous system, BH(4) is a self-protecting factor for NO, or a general neuroprotecting factor via the NO synthase pathway, and has neurotransmitter-releasing function. With regard to human disease, BH(4) deficiency due to autosomal recessive mutations in all enzymes (except sepiapterin reductase) have been described as a cause of hyperphenylalaninaemia. Furthermore, several neurological diseases, including Dopa-responsive dystonia, but also Alzheimer's disease, Parkinson's disease, autism and depression, have been suggested to be a consequence of restricted cofactor availability. PMID:10727395

Thony, B; Auerbach, G; Blau, N



Ex-ante evaluation of biotechnology innovations: the case of folate biofortified rice in China.  


In order to valorize novel biotechnology innovations, there is a need to evaluate ex-ante their market potential. A case in point is biofortification, i.e. the enhancement of the micronutrient content of staple crops through conventional or genetic breeding techniques. In a recent article in Nature Biotechnology, for example, De Steur et al. (2010) demonstrated the large potential consumer health benefits of folate biofortified rice as a means to reduce folate deficiency and Neural-Tube Defects. By focusing on a Chinese high-risk region of Neural-Tube Defects, the current study defines the potential cost-effectiveness of this genetically modified crop where the need to improve folate intake levels is highest. Building on the Disability-Adjusted Life Years (DALY) approach, both the potential health impacts and costs of its implementation are measured and benchmarked against similar innovations. The results show that this transgenic crop could be a highly cost-effective product innovation (US$ 120.34 - US$ 40.1 per DALY saved) to alleviate the large health burden of folate deficiency and reduce the prevalence of neural-tube birth defects. When compared with other biofortified crops and target regions, folate biofortified rice in China has a relatively high health impact and moderate cost-effectiveness. This research further supports the need for, and importance of ex-ante evaluation studies in order to adequately market and, thus, valorize biotechnology innovations. Although the cost-effectiveness analysis enables to illustrate the market potential of innovative agricultural biotechnology research, further research is required to address policy issues on transgenic biofortification, such as biosafety regulatory requirements. PMID:23072390

De Steur, Hans; Blancquaert, Dieter; Gellynck, Xavier; Lambert, Willy; Van Der Straeten, Dominique



Genetic architecture of vitamin B12 and folate levels uncovered applying deeply sequenced large datasets.  


Genome-wide association studies have mainly relied on common HapMap sequence variations. Recently, sequencing approaches have allowed analysis of low frequency and rare variants in conjunction with common variants, thereby improving the search for functional variants and thus the understanding of the underlying biology of human traits and diseases. Here, we used a large Icelandic whole genome sequence dataset combined with Danish exome sequence data to gain insight into the genetic architecture of serum levels of vitamin B(12) (B12) and folate. Up to 22.9 million sequence variants were analyzed in combined samples of 45,576 and 37,341 individuals with serum B(12) and folate measurements, respectively. We found six novel loci associating with serum B(12) (CD320, TCN2, ABCD4, MMAA, MMACHC) or folate levels (FOLR3) and confirmed seven loci for these traits (TCN1, FUT6, FUT2, CUBN, CLYBL, MUT, MTHFR). Conditional analyses established that four loci contain additional independent signals. Interestingly, 13 of the 18 identified variants were coding and 11 of the 13 target genes have known functions related to B(12) and folate pathways. Contrary to epidemiological studies we did not find consistent association of the variants with cardiovascular diseases, cancers or Alzheimer's disease although some variants demonstrated pleiotropic effects. Although to some degree impeded by low statistical power for some of these conditions, these data suggest that sequence variants that contribute to the population diversity in serum B(12) or folate levels do not modify the risk of developing these conditions. Yet, the study demonstrates the value of combining whole genome and exome sequencing approaches to ascertain the genetic and molecular architectures underlying quantitative trait associations. PMID:23754956

Grarup, Niels; Sulem, Patrick; Sandholt, Camilla H; Thorleifsson, Gudmar; Ahluwalia, Tarunveer S; Steinthorsdottir, Valgerdur; Bjarnason, Helgi; Gudbjartsson, Daniel F; Magnusson, Olafur T; Sparsø, Thomas; Albrechtsen, Anders; Kong, Augustine; Masson, Gisli; Tian, Geng; Cao, Hongzhi; Nie, Chao; Kristiansen, Karsten; Husemoen, Lise Lotte; Thuesen, Betina; Li, Yingrui; Nielsen, Rasmus; Linneberg, Allan; Olafsson, Isleifur; Eyjolfsson, Gudmundur I; Jørgensen, Torben; Wang, Jun; Hansen, Torben; Thorsteinsdottir, Unnur; Stefánsson, Kari; Pedersen, Oluf



Genetic Architecture of Vitamin B12 and Folate Levels Uncovered Applying Deeply Sequenced Large Datasets  

PubMed Central

Genome-wide association studies have mainly relied on common HapMap sequence variations. Recently, sequencing approaches have allowed analysis of low frequency and rare variants in conjunction with common variants, thereby improving the search for functional variants and thus the understanding of the underlying biology of human traits and diseases. Here, we used a large Icelandic whole genome sequence dataset combined with Danish exome sequence data to gain insight into the genetic architecture of serum levels of vitamin B12 (B12) and folate. Up to 22.9 million sequence variants were analyzed in combined samples of 45,576 and 37,341 individuals with serum B12 and folate measurements, respectively. We found six novel loci associating with serum B12 (CD320, TCN2, ABCD4, MMAA, MMACHC) or folate levels (FOLR3) and confirmed seven loci for these traits (TCN1, FUT6, FUT2, CUBN, CLYBL, MUT, MTHFR). Conditional analyses established that four loci contain additional independent signals. Interestingly, 13 of the 18 identified variants were coding and 11 of the 13 target genes have known functions related to B12 and folate pathways. Contrary to epidemiological studies we did not find consistent association of the variants with cardiovascular diseases, cancers or Alzheimer's disease although some variants demonstrated pleiotropic effects. Although to some degree impeded by low statistical power for some of these conditions, these data suggest that sequence variants that contribute to the population diversity in serum B12 or folate levels do not modify the risk of developing these conditions. Yet, the study demonstrates the value of combining whole genome and exome sequencing approaches to ascertain the genetic and molecular architectures underlying quantitative trait associations. PMID:23754956

Thorleifsson, Gudmar; Ahluwalia, Tarunveer S.; Steinthorsdottir, Valgerdur; Bjarnason, Helgi; Gudbjartsson, Daniel F.; Magnusson, Olafur T.; Spars?, Thomas; Albrechtsen, Anders; Kong, Augustine; Masson, Gisli; Tian, Geng; Cao, Hongzhi; Nie, Chao; Kristiansen, Karsten; Husemoen, Lise Lotte; Thuesen, Betina; Li, Yingrui; Nielsen, Rasmus; Linneberg, Allan; Olafsson, Isleifur; Eyjolfsson, Gudmundur I.; J?rgensen, Torben; Wang, Jun; Hansen, Torben; Thorsteinsdottir, Unnur; Stefansson, Kari; Pedersen, Oluf



Plant biochemistry: Anthocyanin biosynthesis in roses  

Microsoft Academic Search

Anthocyanin is the principal pigment in flowers, conferring intense red-to-blue cyanic colours on petals and helping to attract pollinators. Its biosynthesis involves glycosylation steps that are important for the stability of the pigment and for its aqueous solubility in vacuoles. Here we describe anthocyanin biosynthesis in roses (Rosa hybrida), which is unlike the pathway used in other flowers in that

Jun Ogata; Yoshiaki Kanno; Yoshio Itoh; Hidehito Tsugawa; Masahiko Suzuki



Biosynthesis of mycobacterial methylglucose lipopolysaccharides.  


Mycobacterial pathogenesis is closely associated with a unique cell envelope rich in complex carbohydrates and unique lipids, among which are the mycolic acids. Mycobacteria also synthesize unique intracellular polymethylated polysaccharides (PMPSs), namely methylglucose lipopolysaccharides (MGLPs), which are acylated with short-chain fatty acids, and methylmannose polysaccharides (MMPs). Since PMPSs modulate the synthesis of long-chain fatty acids in vitro, the possibility of a similar role in vivo and the regulation of mycolic acids assembly have been anticipated. Unlike MGLPs, MMPs have been identified in M. smegmatis and other fast-growing mycobacteria but not in M. tuberculosis, implying an essential role for MGLPs in this pathogen and turning the biosynthetic enzymes into attractive drug targets. The genome of M. tuberculosis was decoded 14 years ago but only recently has the identity of the genes involved in MGLPs biosynthesis been investigated. Two gene clusters (Rv1208-Rv1213 and Rv3030-Rv3037c) containing a few genes considered to be essential for M. tuberculosis growth, have initially been proposed to coordinate MGLPs biosynthesis. Among these genes, only the product of Rv1208 for the first step in the MGLPs pathway has, so far, been crystallized and its three-dimensional structure been determined. However, recent results indicate that at least three additional clusters may be involved in this pathway. The functional assignment of authentic roles to some of these M. tuberculosis H37Rv genes sheds new light on the intricacy of MGLPs biogenesis and renewed interest on their biological role. PMID:22678749

Mendes, Vitor; Maranha, Ana; Alarico, Susana; Empadinhas, Nuno



Serum folate and vitamin B12 levels in acute and chronic renal disease. Effect of peritoneal dialysis.  


Serum folate and vitamin B(12) levels have been measured in 32 patients with renal failure. The initial mean serum folate level was raised above normal in seven patients with acute renal failure whereas the mean level in eight patients severely ill from chronic renal failure was significantly lower than normal. Serum folate levels fell during peritoneal dialysis and rose between dialyses in all these patients and also in one patient who was dialysed for acute pancreatitis.The mean serum B(12) level was raised in patients with both acute and chronic renal failure, but there was no consistent change in serum B(12) level during dialysis.Hypersegmented polymorphs were present in the peripheral blood film of most of the patients with acute or chronic renal failure. Their presence bore no relation to the clinical state, blood urea, serum folate, or serum B(12) level of the patients. PMID:5776209

Sevitt, L H; Hoffbrand, A V



Combined dietary folate, vitamin B-12, and vitamin B-6 intake influences plasma docosahexaenoic acid concentration in rats  

E-print Network

Background: Folate, vitamin B-12, and vitamin B-6 are essential nutritional components in one-carbon metabolism and are required for methylation capacity. The availability of these vitamins may therefore modify methylation ...

van Wijk, Nick


Application of stable isotope dilution assays based on liquid chromatography–tandem mass spectrometry for the assessment of folate bioavailability  

Microsoft Academic Search

A pilot study was performed to prove the suitability of stable isotope dilution assays for assessing the bioavailability of endogenous folates in foods. By using [2H4]folic acid, [2H4]tetrahydrofolate, [2H4]5-methyltetrahydrofolate, [2H4]5-formyltetrahydrofolate and [2H4]10-formylfolic acid as internal standards, folates in spinach, apple juice and blood plasma were quantified by liquid chromatography coupled to tandem mass spectrometry. To liberate the pteroyl monoglutamates, sample

Michael Rychlik; Michael Netzel; Inga Pfannebecker; Thomas Frank; Irmgard Bitsch



Cobalamin and Folate Status in 6 to 35 Months Old Children Presenting with Acute Diarrhea in Bhaktapur, Nepal  

PubMed Central

Background Cobalamin and folate are essential micronutrients and are important in DNA and RNA synthesis, cell proliferation, growth, hematopoiesis, and cognitive function. However, data on cobalamin and folate status are lacking particularly from young children residing in low and middle income countries. Objective To measure cobalamin and folate status and identifies their predictors among 6 to 35 months old children presenting with acute diarrhea. Design This was a cross-sectional study in 823 children presenting with acute diarrhea. We measured plasma cobalamin, folate, methylmalonic acid and total homocysteine who sought treatment for acute diarrhea between June 1998 and August 2000. Results The mean (SD) plasma concentrations of cobalamin, folate, total homocysteine and methylmalonic acid were 206 (124) pmol/L, 55 (32) nmol/L, 11.4 (5.6) µmol/L and 0.79 (1.2) µmol/L, respectively. The prevalence of low plasma cobalamin (<150 pmol/L) was 41% but less than 2% (15) children had low folate concentration (<10 nmol/L). Plasma homocysteine and methylmalonic acid concentrations were negatively associated with cobalamin concentration but not associated with folate status. The prevalence of cobalamin deficiency was higher in breastfed than non-breastfed children (44% vs 24%; p?=?<0.001). The prevalence of hyperhomocysteinemia (>10 µmol/L) and elevated methylmalonic acid (>0.28 µmol/L) were 73% and 52%, respectively. In the regression analyses, the plasma cobalamin concentration was positively associated with age, and introduction of animal or formula milk. Conclusions Our study indicated that poor cobalamin status was common particularly among breastfed children. Folate deficiency was virtually none existent. Possible consequences of cobalamin deficiency in young children need to be explored. PMID:24594935

Ulak, Manjeswori; Chandyo, Ram K.; Adhikari, Ramesh K.; Sharma, Pushpa R.; Sommerfelt, Halvor; Refsum, Helga; Strand, Tor A.



Consumption of folic acid-fortified bread improves folate status in women of reproductive age in Chile.  


Since January 2000 the Chilean Ministry of Health has required the fortification of wheat flour with folic acid (FA) at a concentration of 2.2 mg FA/kg in order to reduce the risk of neural tube defects (NTD) in newborns. This policy was expected to result in a mean additional intake of approximately 400 microg FA/d. We assessed the effectiveness of the FA flour fortification program on bread folate content and on blood folate concentration in women of childbearing age in Santiago, Chile. The prefortification folate status of 751 healthy women of reproductive age was assessed. The folate content of 100 bread samples bought at retail bakeries was measured, average wheat flour consumption was estimated and postfortification FA dietary intake was calculated. The effect of flour fortification on blood folate concentration in this group of women (n = 605) was evaluated in a follow-up study. Blood folate concentrations of the 605 women in the follow-up group increased (P < 0.0001) following fortification. Before fortification the mean serum and red blood cell folate concentrations were 9.7 +/- 4.3 and 290 +/- 102 nmol/L, respectively, compared with 37.2 +/- 9.5 and 707 +/- 179 nmol/L postfortification, respectively. The mean FA content of bread was 2020 +/- 940 micro g/kg. The median FA intake of the group evaluated postfortification was 427 microg/d (95% CI 409-445) based on an estimated intake of 219 g/d (95% CI 201-229) of wheat flour, mainly as bread. Fortification of wheat flour substantially improved folate status in a population of women of reproductive age in Chile. The effect of the FA fortification program on the occurrence of NTD is currently being assessed. PMID:14519804

Hertrampf, Eva; Cortés, Fanny; Erickson, J David; Cayazzo, Marisol; Freire, Wilma; Bailey, Lynn B; Howson, Christopher; Kauwell, Gail P A; Pfeiffer, Christine



Vitamin D, folate, and potential early lifecycle environmental origin of significant adult phenotypes  

PubMed Central

Background and objectives: Vitamin D and folate are highly UV sensitive, and critical for maintaining health throughout the lifecycle. This study examines whether solar irradiance during the first trimester of pregnancy influences vitamin D receptor (VDR) and nuclear folate gene variant occurrence, and whether affected genes influence late-life biochemical/clinical phenotypes. Methodology: 228 subjects were examined for periconceptional exposure to solar irradiance, variation in vitamin D/folate genes (polymerase chain reaction (PCR)), dietary intake (food frequency questionnaire (FFQ)) and important adult biochemical/clinical phenotypes. Results: Periconceptional solar irradiance was associated with VDR-BsmI (P = 0.0008wk7), TaqI (P = 0.0014wk7) and EcoRV (P = 0.0030wk6) variant occurrence between post-conceptional weeks 6–8, a period when ossification begins. Similar effects were detected for other VDR gene polymorphisms. Periconceptional solar irradiance was also associated with 19 bp del-DHFR (P = 0.0025wk6), and to a lesser extent C1420T-SHMT (P = 0.0249wk6), a folate-critical time during embryogenesis. These same genes were associated with several late-life phenotypes: VDR-BsmI, TaqI and ApaI determined the relationship between dietary vitamin D and both insulin (P < 0.0001/BB, 0.0007/tt and 0.0173/AA, respectively) and systolic blood pressure (P = 0.0290/Bb, 0.0299/Tt and 0.0412/AA, respectively), making them important early and late in the lifecycle. While these and other phenotype associations were found for the VDR variants, folate polymorphism associations in later-life were limited to C1420T-SHMT (P = 0.0037 and 0.0297 for fasting blood glucose and HbA1c levels, respectively). We additionally report nutrient–gene relationships with body mass index, thiol/folate metabolome, cognition, depression and hypertension. Furthermore, photoperiod at conception influenced occurrence of VDR-Tru9I and 2R3R-TS genotypes (P = 0.0120 and 0.0360, respectively). Conclusions and implications: Findings identify environmental and nutritional agents that may interact to modify gene–phenotype relationships across the lifecycle, offering new insight into human ecology. This includes factors related to both disease aetiology and the evolution of skin pigmentation. PMID:24699387

Lucock, Mark; Yates, Zoe; Martin, Charlotte; Choi, Jeong-Hwa; Boyd, Lyndell; Tang, Sa; Naumovski, Nenad; Furst, John; Roach, Paul; Jablonski, Nina; Chaplin, George; Veysey, Martin



Isolation and characterization of folate-producing bacteria from oat bran and rye flakes.  


The aim of this research was to identify endogenous bacteria in commercial oat bran and rye flake products in order to study their folate production capability while maintaining the soluble dietary fibre components in physiologically active, unhydrolyzed form. Fourty-two bacteria were isolated from three different oat bran products and 26 bacteria from one rye flake consumer product. The bacteria were tentatively identified by sequence analysis of the 16S rRNA genes. The identification results revealed up to 18 distinct bacterial species belonging to 13 genera in oat bran, and 11 species belonging to 10 genera in rye flakes. The most common bacterial genus in oat bran was Pantoea, followed by Acinetobacter, Bacillus, and Staphylococcus. Pantoea species dominated also in rye flakes. The extracellular enzymatic activities of the isolates were studied by substrate hydrolysis plate assays. Nearly 80% of the isolates hydrolyzed carboxymethylcellulose, whereas starch-degrading activities were surprisingly rare (10%). Beta-glucan was hydrolyzed by 19% of the isolates. Protease, lipase or xylanase activity was expressed by 24%, 29%, and 16%, respectively, of the isolates. Representatives of the genera Bacillus, Curtobacterium, Pedobacter, and Sanguibacter showed the highest diversity of enzymatic activities, whereas members of Janthinobacterium and Staphylococcus possessed no hydrolytic activities for the substrates studied. Production capability for total folates was analyzed from aerobic cell cultures at the stationary growth phase. The amount of folates was determined separately for the cell mass and the supernatant by microbiological assay. For comparison, folate production was also examined in a number of common lactic acid bacteria. The best producers in oat bran belonged to the genera Bacillus, Janthinobacterium, Pantoea, and Pseudomonas, and those in rye flakes to Chryseobacterium, Erwinia, Plantibacter, and Pseudomonas. Supernatant folate contents were high for Bacillus, Erwinia, Janthinobacterium, Pseudomonas, and Sanguibacter. Compared to the endogenous bacteria, lactic acid bacteria were poor folate producers. The results of this work provide the first insight into the potential role of endogenous microflora in modulating the nutrient levels of oat and rye based cereal products, and pave way to future innovations of nutritionally improved cereal foods. PMID:20678822

Herranen, Mirkka; Kariluoto, Susanna; Edelmann, Minnamari; Piironen, Vieno; Ahvenniemi, Katja; Iivonen, Vilja; Salovaara, Hannu; Korhola, Matti



Maternal and Infant Gene-Folate Interactions and the Risk of Neural Tube Defects  

PubMed Central

Neural tube defects (NTDs) are common, serious malformations with a complex etiology that suggests involvement of both genetic and environmental factors. The authors evaluated maternal or offspring folate-related gene variants and interactions between the gene variants and maternal intake of folates on the risk of NTDs in their offspring. A case-control study was conducted on mothers and/or their fetuses and infants who were born in California from 1999–2003 with an NTD (cases n = 222, including 24 mother-infant pairs) or without a major malformation (controls n = 454, including 186 mother-infant pairs). Maternal intake of folates was assessed by food frequency questionnaire and genotyping was performed on samples from mothers and infants. For mothers in the lowest folate-intake group, risk of NTDs in offspring was significantly decreased for maternal MTHFR SNPs rs1476413, rs1801131 and rs1801133 (odds ratio (OR) = 0.55, 80% confidence interval (CI): 0.20, 1.48; OR = 0.58, 80% CI: 0.24, 1.43; OR = 0.69, 80% CI: 0.41, 1.17, respectively), and TYMS SNPs rs502396 and rs699517 (OR= 0.91, 80% CI: 0.53, 1.56; OR = 0.70, 80% CI: 0.38, 1.29). A gene-only effect was observed for maternal SHMT1 SNP rs669340 (OR = 0.69, 95% CI: 0.49, 0.96). When there was low maternal folate intake, risk of NTDs was significantly increased for infant MTHFD1 SNPs rs2236224, rs2236225 and rs11627387 (OR = 1.58, 80% CI: 0.99, 2.51; OR = 1.53, 80% CI: 0.95, 2.47; OR = 4.25, 80% CI: 2.33, 7.75, respectively) and SHMT1 SNP rs12939757 (OR = 2.01, 80% CI: 1.20, 3.37), but decreased for TYMS SNP rs2847153 (OR = 0.73, 80% CI: 0.37, 1.45). Although power to detect interaction effects was low for this birth defects association study, the gene-folate interactions observed in this study represent preliminary findings that will be useful for informing future studies on the complex etiology of NTDs. PMID:22903727

Etheredge, Analee J.; Finnell, Richard H.; Carmichael, Suzan L.; Lammer, Edward J.; Zhu, Huiping; Mitchell, Laura E.; Shaw, Gary M.



Comparison of total folate concentrations in foods determined by microbiological assay at several experienced U.S. commercial laboratories.  


Analysis of total folate concentration measured by microbiological assay in a variety of foods submitted in a routine manner to experienced laboratories that regularly perform folate analysis on fee-for-service basis was evaluated. Homogenates of fresh strawberries, frozen spinach, orange juice, frozen meat and vegetable pizza, dry macaroni, and dried pinto beans were prepared and stored under conditions previously determined to maintain stability of folate content. An aliquot of each composite and of 3 certified reference materials were sent on each of 4 occasions to 4 laboratories. Results for macaroni and pizza, the only folic acid-fortified foods, had considerably lower between-laboratory variation (CV(B)) with CV(B) of 9-11% versus >45% for other foods. Mean total folate ranged from 14 to 279 microg/100 g for a mixed vegetable reference material, from 5 to 70 microg/100 g for strawberries, and from 28 to 81 microg/100 g for wholemeal flour. Only 1 laboratory reported using a tri-enzyme extraction, and all laboratories used folic acid fortified foods as internal control materials. Users of commercial total folate analysis should understand the uncertainty in values determined by microbiological assay, particularly for foods containing primarily naturally occurring folate, which may not be apparent when replicate samples are not submitted for analysis. PMID:16001856

Koontz, John L; Phillips, Katherine M; Wunderlich, Kelli M; Exler, Jacob; Holden, Joanne M; Gebhardt, Susan E; Haytowitz, David B



Erythrocyte folate concentrations, CpG methylation at genomically imprinted domains, and birth weight in a multiethnic newborn cohort.  


Epigenetic mechanisms are proposed to link maternal concentrations of methyl group donor nutrients with the risk of low birth weight. However, empirical data are lacking. We have examined the association between maternal folate and birth weight and assessed the mediating role of DNA methylation at nine differentially methylated regions (DMRs) of genomically imprinted genes in these associations. Compared with newborns of women with folate levels in the lowest quartile, birth weight was higher in newborns of mothers in the second (? = 143.2, se = 63.2, P = 0.02), third (? = 117.3, se = 64.0, P = 0.07), and fourth (? = 133.9, se = 65.2, P = 0.04) quartiles, consistent with a threshold effect. This pattern of association did not vary by race/ethnicity but was more apparent in newborns of non-obese women. DNA methylation at the PLAGL1, SGCE, DLK1/MEG3 and IGF2/H19 DMRs was associated with maternal folate levels and also birth weight, suggestive of threshold effects. MEG3 DMR methylation mediated the association between maternal folate levels and birth weight (P =0.06). While the small sample size and partial scope of examined DMRs limit our conclusions, our data suggest that, with respect to birth weight, no additional benefits may be derived from increased maternal folate concentrations, especially in non-obese women. These data also support epigenetic plasticity as a key mechanistic response to folate availability during early fetal development. PMID:24874916

Hoyo, Cathrine; Daltveit, Anne Kjersti; Iversen, Edwin; Benjamin-Neelon, Sara E; Fuemmeler, Bernard; Schildkraut, Joellen; Murtha, Amy P; Overcash, Francine; Vidal, Adriana C; Wang, Frances; Huang, Zhiqing; Kurtzberg, Joanne; Seewaldt, Victoria; Forman, Michele; Jirtle, Randy L; Murphy, Susan K



Biosynthesis and deficiencies of glycosylphosphatidylinositol  

PubMed Central

At least 150 different human proteins are anchored to the outer leaflet of the plasma membrane via glycosylphosphatidylinositol (GPI). GPI preassembled in the endoplasmic reticulum is attached to the protein’s carboxyl-terminus as a post-translational modification by GPI transamidase. Twenty-two PIG (for Phosphatidyl Inositol Glycan) genes are involved in the biosynthesis and protein-attachment of GPI. After attachment to proteins, both lipid and glycan moieties of GPI are structurally remodeled in the endoplasmic reticulum and Golgi apparatus. Four PGAP (for Post GPI Attachment to Proteins) genes are involved in the remodeling of GPI. GPI-anchor deficiencies caused by somatic and germline mutations in the PIG and PGAP genes have been found and characterized. The characteristics of the 26 PIG and PGAP genes and the GPI deficiencies caused by mutations in these genes are reviewed. PMID:24727937




Rho GTPases RhoA and Rac1 Mediate Effects of Dietary Folate on Metastatic Potential of A549 Cancer Cells through the Control of Cofilin Phosphorylation.  


Folate, an important nutrient in the human diet, has been implicated in cancer, but its role in metastasis is not established. We have shown previously that the withdrawal of medium folate leads to the inhibition of migration and invasion of A549 lung carcinoma cells. Here we have demonstrated that medium folate regulates the function of Rho GTPases by enabling their carboxyl methylation and translocation to plasma membrane. Conversely, the lack of folate leads to the retention of these proteins in endoplasmic reticulum. Folate also promoted the switch from inactive (GDP-bound) to active (GTP-bound) GTPases, resulting in the activation of downstream kinases p21-activated kinase and LIM kinase and phosphorylation of the actin-depolymerizing factor cofilin. We have further demonstrated that in A549 cells two GTPases, RhoA and Rac1, but not Cdc42, are immediate sensors of folate status: the siRNA silencing of RhoA or Rac1 blocked effects of folate on cofilin phosphorylation and cellular migration and invasion. The finding that folate modulates metastatic potential of cancer cells was confirmed in an animal model of lung cancer using tail vein injection of A549 cells in SCID mice. A folate-rich diet enhanced lung colonization and distant metastasis to lymph nodes and decreased overall survival (35 versus 63 days for mice on a folate-restricted diet). High folate also promoted epithelial-mesenchymal transition in cancer cells and experimental mouse tumors. Our study provides experimental evidence for a mechanism of metastasis promotion by dietary folate and highlights the interaction between nutrients and metastasis-related signaling. PMID:25086046

Oleinik, Natalia V; Helke, Kristi L; Kistner-Griffin, Emily; Krupenko, Natalia I; Krupenko, Sergey A



Maytansine-loaded star-shaped folate-core PLA-TPGS nanoparticles enhancing anticancer activity  

PubMed Central

The efficient delivery of therapeutic molecule agents into target cells of interest is a critical challenge to broad application of non-viral vector systems. In this research, maytansine-loaded star-shaped folate-core polylactide-D-?-tocopheryl polyethylene glycol 1000 succinate (FA-PLA-TPGS) block copolymer was applied to be a vector of maytansine for folate receptor positive (FR+) breast cancer therapy. The uptake of maytansine nanoparticles by SKBR3 cells were observed by fluorescence microscopy and confocal laser scanning microscopy. The cell viability of maytansine-NPs in SKBR3 cells was assessed according to the changed level of intracellular microtubules and apoptosis-associated proteins. The cytotoxicity of the SKBR3 cells was significantly increased by maytansine-NPs when compared with control groups. In conclusion, the maytansine-NPs offer a considerable potential formulation for FR-expressing tumor targeting biotherapy. PMID:25360217

Tang, Xiaolong; Dai, Hong; Zhu, Yongxiang; Tian, Ye; Zhang, Rongbo; Mei, Rengbiao; Li, Deqiang



Adding folate to the contraceptive pill: a new concept for the prevention of neural tube defects.  


Although it is proven for a long time that folic acid supplementation in the periconceptional period can prevent neural tube defects (NTDs) effectively, all measures taken so far including food fortification and awareness campaigns so far had only limited success. Since more than 50% of the pregnant women in Europe get pregnant after they have used oral contraceptives (OCs) before, OCs are an ideal vehicle to increase not only the awareness for periconceptional folate application, but they can also help to bridge the gap between the recognition of a pregnancy and closure of the neural tube which is before day 26. In order to reach a truly protective folate level at the critical time period during pregnancy, now OCs are available which contain metafolin. The availability of this innovative type of OC will significantly reduce the number of NTDs. PMID:22272814

Holzgreve, Wolfgang; Pietrzik, Klaus; Koletzko, Berthold; Eckmann-Scholz, Christel



18?F-click labeling and preclinical evaluation of a new 18?F-folate for PET imaging  

PubMed Central

Background The folate receptor (FR) is a well-established target for tumor imaging and therapy. To date, only a few 18?F-folate conjugates via 18?F-prosthetic group labeling for positron emission tomography (PET) imaging have been developed. To some extent, they all lack the optimal balance between efficient radiochemistry and favorable in vivo characteristics. Methods A new clickable olate precursor was synthesized by regioselective coupling of folic acid to 11-azido-3,6,9-trioxaundecan-1-amine at the ?-position of the glutamic acid residue. The non-radioactive reference compound was synthesized via copper-catalyzed azide-alkyne cycloaddition of 3-(2-(2-(2-fluoroethoxy)ethoxy)ethoxy)prop-1-yne and ?-(11-azido-3,6,9-trioxaundecanyl)folic acid amide. The radiosynthesis was accomplished in two steps: at first a 18?F-fluorination of 2-(2-(2-(prop-2-yn-1-yloxy)ethoxy)ethoxy)ethyl-4-methylbenzenesulfonate, followed by a 18?F-click reaction with the ?-azido folate. The in vitro, ex vivo, and in vivo behaviors of the new 18?F-folate were investigated using FR-positive human KB cells in displacement assays and microPET studies using KB tumor-bearing mice. Results The new 18?F-folate with oligoethylene spacers showed reduced lipophilicity in respect to the previously developed 18?F-click folate with alkyl spacers and excellent affinity (Ki?=?1.6 nM) to the FR. Combining the highly efficient 18?F-click chemistry and a polar oligoethylene-based 18?F-prosthetic group facilitated these results. The overall radiochemical yield of the isolated and formulated product averages 8.7%. In vivo PET imaging in KB tumor-bearing mice showed a tumor uptake of 3.4% ID/g tissue, which could be reduced by FR blockade with native folic acid. Although the new 18?F-oligoethyleneglycole (OEG)-folate showed reduced hepatobiliary excretion over time, a distinct unspecific abdominal background was still observed. Conclusions A new 18?F-folate was developed, being available in very high radiochemical yields via a fast and convenient two-step radiosynthesis. The new 18?F-OEG-folate showed good in vivo behavior and lines up with several recently evaluated 18?F-labeled folates. PMID:24041035



Folate-related gene variants in Irish families affected by neural tube defects  

PubMed Central

Periconceptional folic acid use can often prevent neural tube defects (NTDs). Variants of genes involved in folate metabolism in mothers and children have been associated with occurrence of NTDs. We identified Irish families with individuals affected by neural tube defects. In these families, we observed that neural tube defects and birth defects overall occurred at a higher rate in the maternal lineage compared with the paternal lineage. The goal of this study was to look for evidence for genetic effects that could explain the discrepancy in the occurrence of these birth defects in the maternal vs. paternal lineage. We genotyped blood samples from 322 individuals from NTD-affected Irish families, identified through their membership in spina bifida associations. We looked for differences in distribution in maternal vs. paternal lineages of five genetic polymorphisms: the DHFR 19 bp deletion, MTHFD1 1958G>A, MTHFR 1298A>C, MTHFR 677C>T, and SLC19A1 80A>G. In addition to looking at genotypes individually, we determined the number of genotypes associated with decreased folate metabolism in each relative (“risk genotypes”) and compared the distribution of these genotypes in maternal vs. paternal relatives. Overall, maternal relatives had a higher number of genotypes associated with lower folate metabolism than paternal relatives (p = 0.017). We expected that relatives would share the same risk genotype as the individuals with NTDs and/or their mothers. However, we observed that maternal relatives had an over-abundance of any risk genotype, rather than one specific genotype. The observed genetic effects suggest an epigenetic mechanism in which decreased folate metabolism results in epigenetic alterations related to the increased rate of NTDs and other birth defects seen in the maternal lineage. Future studies on the etiology of NTDs and other birth defects could benefit from including multigenerational extended families, in order to explore potential epigenetic mechanisms. PMID:24223580

Fisk Green, Ridgely; Byrne, Julianne; Crider, Krista S.; Gallagher, Margaret; Koontz, Deborah; Berry, Robert J.



Quantification of Pantothenic Acid and Folates by Stable Isotope Dilution Assays  

Microsoft Academic Search

Stable isotope dilution assays for the quantification of pantothenic acid and folates in foods by using four-fold labeled isotopomers of the vitamins as internal standards (IS) were developed. The use of labeled IS enabled to exactly correct losses during cleanup and derivatization.Pantothenic acid and its labeled isotopomer were detected as trimethylsilyl derivatives by gas chromatography–mass spectrometry. In starch a detection

Michael Rychlik; Achim Freisleben



Predictors of Vitamin B6 and Folate Concentrations in Older Persons: The InCHIANTI Study  

Microsoft Academic Search

Background: Low dietary intake and low serum concen- trations of vitamin B6 and\\/or folate are associated with increased risk of vascular events, possibly because of their association with inflammation, which plays a crucial role in the pathogenesis of cardiovascular dis- eases. Methods: Using data from 1320 participants in the population-based InCHIANTI study (586 men and 734 women; median age, 69

Anna Maria Gori; Francesco Sofi; Anna Maria Corsi; Alessandra Gazzini; Ilaria Sestini; Fulvio Lauretani; Stefania Bandinelli; Gian Franco Gensini; Luigi Ferrucci; Rosanna Abbate



Folate-vinca alkaloid conjugates for cancer therapy: a structure-activity relationship.  


Vintafolide is a potent folate-targeted vinca alkaloid small molecule drug conjugate (SMDC) that has shown promising results in multiple clinical oncology studies. Structurally, vintafolide consists of 4 essential modules: (1) folic acid, (2) a hydrophilic peptide spacer, (3) a disulfide-containing, self-immolative linker, and (4) the cytotoxic drug, desacetylvinblastine hydrazide (DAVLBH). Here, we report a structure-activity study evaluating the biological impact of (i) substituting DAVLBH within the vintafolide molecule with other vinca alkaloid analogues such as vincristine, vindesine, vinflunine, or vinorelbine; (ii) substituting the naturally (S)-configured Asp-Arg-Asp-Asp-Cys peptide with alternative hydrophilic spacers of varied composition; and (iii) varying the composition of the linker module. A series of vinca alkaloid-containing SMDCs were synthesized and purified by HPLC and LCMS. The SMDCs were screened in vitro against folate receptor (FR)-positive cells, and anti-tumor activity was tested against well-established subcutaneous FR-positive tumor xenografts. The cytotoxic and anti-tumor activity was directly compared to that produced by vintafolide. Among all the folate vinca alkaloid SMDCs tested, DAVLBH-containing SMDCs were active, while those constructed with vincristine, vindesine, or vinorelbine analogues failed to produce meaningful biological activity. Within the DAVLBH series, having a bioreleasable, self-immolative linker system was found to be critical for activity since multiple analogues constructed with thioether-based linkers all failed to produce meaningful activity both in vitro and in vivo. Substitutions of some or all of the natural amino acids within vintafolide's hydrophilic spacer module did not significantly change the in vitro or in vivo potency of the SMDCs. Vintafolide remains one of the most potent folate-vinca alkaloid SMDCs produced to date, and continued clinical development is warranted. PMID:24564229

Leamon, Christopher P; Vlahov, Iontcho R; Reddy, Joseph A; Vetzel, Marilynn; Santhapuram, Hari Krishna R; You, Fei; Bloomfield, Alicia; Dorton, Ryan; Nelson, Melissa; Kleindl, Paul; Vaughn, Jeremy F; Westrick, Elaine



Dioxin mediates downregulation of the reduced folate carrier transport activity via the arylhydrocarbon receptor signalling pathway  

SciTech Connect

Dioxins such as 2,3,7,8-tetrachlordibenzo-p-dioxin (TCDD) are common environmental contaminants known to regulate several genes via activation of the transcription factor aryl hydrocarbon receptor (AhR) associated with the development of numerous adverse biological effects. However, comparatively little is known about the molecular mechanisms by which dioxins display their toxic effects in vertebrates. The 5' untranslated region of the hepatocellular Reduced folate carrier (Rfc1; Slc19a1) exhibits AhR binding sites termed dioxin responsive elements (DRE) that have as yet only been found in the promoter region of prototypical TCDD target genes. Rfc1 mediated transport of reduced folates and antifolate drugs such as methotrexate (MTX) plays an essential role in physiological folate homeostasis and MTX cancer chemotherapy. In order to determine whether this carrier represents a target gene of dioxins we have investigated the influence of TCDD on functional Rfc1 activity in rat liver. Pre-treatment of rats with TCDD significantly diminished hepatocellular Rfc1 uptake activity in a time- and dose-dependent manner. In further mechanistic studies we demonstrated that this reduction was due to TCDD-dependent activation of the AhR signalling pathway. We additionally showed that binding of the activated receptor to DRE motifs in the Rfc1 promoter resulted in downregulation of Rfc1 gene expression and reduced carrier protein levels. As downregulation of pivotal Rfc1 activity results in functional folate deficiency associated with an elevated risk of cardiovascular diseases or carcinogenesis, our results indicate that deregulation of this essential transport pathway represents a novel regulatory mechanism how dioxins display their toxic effects through the Ah receptor.

Halwachs, Sandra, E-mail: halwachs@vetmed.uni-leipzig.d [Institute of Pharmacology, Pharmacy and Toxicology, Faculty of Veterinary Medicine, University of Leipzig, Leipzig (Germany); Lakoma, Cathleen [Institute of Pharmacology, Pharmacy and Toxicology, Faculty of Veterinary Medicine, University of Leipzig, Leipzig (Germany); Gebhardt, Rolf [Institute of Biochemistry, Faculty of Medicine, University of Leipzig, Leipzig (Germany); Schaefer, Ingo; Seibel, Peter [Molecular Cell Therapy, Center for Biotechnology and Biomedicine, Faculty of Medicine, University of Leipzig, Leipzig (Germany); Honscha, Walther [Institute of Pharmacology, Pharmacy and Toxicology, Faculty of Veterinary Medicine, University of Leipzig, Leipzig (Germany)



MR imaging of antigen-induced arthritis with a new, folate receptor-targeted contrast agent.  


The purpose of this study was to investigate if the new folate receptor-targeted Gd-chelate P866 may enhance immune-mediated arthritis. A monoarthritis was induced in the right knee of 15 Sprague-Dawley rats. MR imaging of both knees was performed at 2 T before and up to 2 h and 24 h after injection (p.i.) of P866 (n = 3 dose finding study and n = 6, 0.02 mmol Gd/kg), the non-FR targeted P866 analog P1001 (n = 3 at 24 h after P866-administration, 0.02 mmol Gd/kg) or Gd-DOTA (n = 6, 0.1 mmol Gd/kg). Pulse sequences comprised T(1)-SPGR 80 degrees /50 ms/1.7 ms (flip angle/TR/TE) and inversion recovery 10 degrees /3000 ms/1500 ms/50-3050, 10 000 ms (flip angle/TR/TE/TI) sequences. DeltaSI-data and T(1)-relaxation times of arthritic knees and contralateral normal knees were determined. Folate receptor expression was confirmed with histopathology. All three contrast agents showed an initial perfusion effect with significantly higher DeltaSI-data of arthritic knees compared with normal knees (p < 0.05). In addition, P866, but not P1001 or Gd-DOTA, showed a prolonged enhancement of the synovitis. Compared with precontrast values, the T(1)-relaxation times of inflamed synovia were significantly decreased at 2 h p.i. of P866 (p < 0.05), but not P1001 or Gd-DOTA (p > 0.05). Histopathology confirmed the presence of folate receptors in the inflamed joints, but not normal joints. Thus, results suggest a specific accumulation of the folate receptor-targeted Gd-chelate P866 in this arthritis model. PMID:17385788

Saborowski, Olaf; Simon, Gerhard H; Raatschen, Hans-Juergen; Wendland, Michael F; Fu, Yanjun; Henning, Tobias; Baehner, Rick; Corot, Claire; Chen, Mei-Hsiu; Daldrup-Link, Heike E



Red blood cell folate is associated with the development of dysplasia and cancer in ulcerative colitis  

Microsoft Academic Search

Patients with extensive ulcerative colitis have a high risk of developing colon cancer. The etiology of mucosal dysplasia, a premalignant lesion that is used as a screening test in surveillance programs, is unknown. Previously, a case-control study [Lashner et al. (1989) Gastroenterology 97:255–259] suggested that folate supplementation was associated with a 62% reduction in the risk of developing dysplasia or

Bret A. Lashner



Biomarkers of Folate and Vitamin B12 Are Related in Blood and Cerebrospinal Fluid  

Microsoft Academic Search

Background: B-vitamins (folate, B12) are important mi- cronutrients for brain function and essential cofactors for homocysteine (HCY) metabolism. Increased HCY has been related to neurological and psychiatric disor- ders. We studied the role of the B-vitamins in HCY metabolism in the brain. Methods: We studied blood and cerebrospinal fluid (CSF) samples from 72 patients who underwent lumbar puncture. We measured

Rima Obeid; Panagiotis Kostopoulos; Jean-Pierre Knapp; Mariz Kasoha; George Becker; Klaus Fassbender; Wolfgang Herrmann


Micronutrient status in female university students: iron, zinc, copper, selenium, vitamin B12 and folate.  


Young women are at an increased risk of micronutrient deficiencies, particularly due to higher micronutrient requirements during childbearing years and multiple food group avoidances. The objective of this study was to investigate biomarkers of particular micronutrients in apparently healthy young women. Female students (n = 308; age range 18-35 year; Body Mass Index 21.5 ± 2.8 kg/m2; mean ± SD) were recruited to participate in a cross-sectional study. Blood samples were obtained from participants in the fasted state and analysed for biomarkers of iron status, vitamin B12, folate, homocysteine, selenium, zinc, and copper. The results show iron deficiency anaemia, unspecified anaemia, and hypoferritinemia in 3%, 7% and 33.9% of participants, respectively. Low vitamin B12 concentrations (<120 pmol/L) were found in 11.3% of participants, while 4.7% showed sub-clinical deficiency based on serum methylmalonic acid concentrations >0.34 ?mol/L. Folate concentrations below the reference range were observed in 1.7% (serum) or 1% (erythrocytes) of participants, and 99.7% of the participant had erythrocyte-folate concentrations >300 nmol/L. Serum zinc concentrations <10.7 ?mol/L were observed in 2% of participants. Serum copper and selenium concentrations were below the reference range in 23% and 11% of participants, respectively. Micronutrient deficiencies including iron and vitamin B12, and apparent excess of folate are present in educated Australian female students of childbearing age, including those studying nutrition. The effects of dietary behaviours and food choices on markers of micronutrient status require further investigation. PMID:25401503

Fayet-Moore, Flavia; Petocz, Peter; Samman, Samir



Polymorphisms in genes involved in folate metabolism as maternal risk factors for Down syndrome in China  

Microsoft Academic Search

Objective: To explore the relationship between genetic polymorphisms in methylenetetrahydrofolate reductase (MTHFR), methionine\\u000a synthase reductase (MTRR), the central enzymes in folate metabolism that affects DNA methylation and synthesis, and the risk\\u000a of Down syndrome in China. Methods: Genomic DNA was isolated from the peripheral lymphocytes of 64 mothers of children with\\u000a Down syndrome and 70 age matched control subjects. Polymerase

Shao-shuai Wang; Fu-yuan Qiao; Ling Feng; Juan-juan Lv



Folate depletion during pregnancy and lactation reduces genomic DNA methylation in murine adult offspring  

Microsoft Academic Search

The developmental origins of adult health and disease (DOHaD) hypothesis that argues for a causal relationship between under-nutrition\\u000a during early life and increased risk for a range of diseases in adulthood is gaining epidemiological support. One potential\\u000a mechanism mediating these effects is the modulation of epigenetic markings, specifically DNA methylation. Since folate is\\u000a an important methyl donor, alterations in supply

Jill A. McKayKevin; Kevin J. Waltham; Elizabeth A. Williams; John C. Mathers



Micronutrient Status in Female University Students: Iron, Zinc, Copper, Selenium, Vitamin B12 and Folate  

PubMed Central

Young women are at an increased risk of micronutrient deficiencies, particularly due to higher micronutrient requirements during childbearing years and multiple food group avoidances. The objective of this study was to investigate biomarkers of particular micronutrients in apparently healthy young women. Female students (n = 308; age range 18–35 year; Body Mass Index 21.5 ± 2.8 kg/m2; mean ± SD) were recruited to participate in a cross-sectional study. Blood samples were obtained from participants in the fasted state and analysed for biomarkers of iron status, vitamin B12, folate, homocysteine, selenium, zinc, and copper. The results show iron deficiency anaemia, unspecified anaemia, and hypoferritinemia in 3%, 7% and 33.9% of participants, respectively. Low vitamin B12 concentrations (<120 pmol/L) were found in 11.3% of participants, while 4.7% showed sub-clinical deficiency based on serum methylmalonic acid concentrations >0.34 ?mol/L. Folate concentrations below the reference range were observed in 1.7% (serum) or 1% (erythrocytes) of participants, and 99.7% of the participant had erythrocyte-folate concentrations >300 nmol/L. Serum zinc concentrations <10.7 ?mol/L were observed in 2% of participants. Serum copper and selenium concentrations were below the reference range in 23% and 11% of participants, respectively. Micronutrient deficiencies including iron and vitamin B12, and apparent excess of folate are present in educated Australian female students of childbearing age, including those studying nutrition. The effects of dietary behaviours and food choices on markers of micronutrient status require further investigation. PMID:25401503

Fayet-Moore, Flavia; Petocz, Peter; Samman, Samir



Folate, vitamin B12 and total homocysteine levels in neonates from Brazil  

Microsoft Academic Search

Objective:To determine folates, vitamin B12 and total homocysteine levels among neonates from mothers of low or high socioeconomic status.Design:We carried out a cross-sectional transversal study comprising 143 neonates from two maternity hospitals in the city of Salvador, Northeast of Brazil. Cord blood samples were obtained at the time of delivery from newborns from low (group 1, n=77) or high (group

F D Couto; L M O Moreira; D B dos Santos; M G Reis; M S Gonçalves



Association between folate levels and CpG island hypermethylation in normal colorectal mucosa  

PubMed Central

Background Gene-specific promoter methylation of several genes occurs in aging normal tissues and may predispose to tumorigenesis. In the present study, we investigate the association among blood folate levels, and dietary and lifestyle factors with CpG island methylation in normal colorectal mucosa. Methods Subjects were enrolled in a multi-center chemoprevention trial of aspirin or folic acid for the prevention of large bowel adenomas. We collected 1000 biopsies from 389 patients, 501 samples from the right colon and 499 from the rectum at the follow-up colonoscopy. We measured DNA methylation of estrogen receptor alpha (ER?) and secreted frizzled related protein-1 (SFRP1) using bisulfite pyrosequencing. We used Generalized Estimating Equations regression analysis to examine the association between methylation and selected variables. Results For both ER? and SFRP1, percent methylation was significantly higher in the rectum compared to the right colon (p = 0.001). For each 10 years of age, we observed a 1.7 % increase in methylation level for ER? and a 2.9 % increase for SFRP1 (P < 0.0001). African Americans had a significantly lower level of ER? and SFRP1 methylation compared to Caucasians and Hispanics. Higher RBC folate levels were associated with higher levels of both ER? (p=0.03) and SFRP1 methylation (p=0.01). Conclusions Our results suggest that CpG island methylation in normal colorectal mucosa is related to advancing age, race, rectal location, and RBC folate levels. These data have important implications regarding the safety of supplementary folate administration in healthy adults given the hypothesis that methylation in normal mucosa may predispose to colorectal neoplasia. PMID:21149331

Wallace, Kristin; Grau, Maria V.; Levine, Joan A.; Shen, Lanlan; Hamdan, Randala; Chen, Xinli; Gui, Jiang; Haile, Robert W.; Barry, Elizabeth L.; Ahnen, Dennis; McKeown-Eyssen, Gail; Baron, John A.; Issa, Jean Pierre J.



Preparation, Characterization and Pharmacokinetics of Folate Receptor-Targeted Liposomes for Docetaxel Delivery  

PubMed Central

A novel liposomal formulation of docetaxel targeting the folate receptor (FR) was synthesized and characterized. Liposomal formulations are less toxic and can provide longer systemic circulation time than the Tween 80 and ethanol based clinical formulation of docetaxel. Folate receptor-? (FR) is frequently over-expressed on epithelial cancer cells. Therefore, FR targeted liposomes can potentially enhance tumor cell uptake and antitumor efficacy of encapsulated drugs. The formulation studied had the compositions of egg phosphatidylcholine/cholesterol/methoxy-polyethylene glycol (PEG)2,000-distesroylphnosphatidylethanolamine/folate-PEG3,350-cholesteryl hemisuccinate (ePC/Chol/mPEG-DSPE/folate-PEG-CHEMS) at ratios of (80:15:4.5:0.5, mol/mol) and a drug-to-lipid ratio of 1:20, wt/wt. Sucrose was used as a lyoprotectant. The liposomes were prepared by thin-film hydration, polycarbonate membrane extrusion, followed by lyophilization. They remained stable for more than 5 months when stored as lyophilized powder and for 72 h at 4 °C following rehydration. The mean particle size of reconstituted liposomes ranged from 110 to 120 nm. FR-targeted liposomes of the same lipid composition entrapping calcein were shown to be efficiently taken up by FR + KB oral carcinoma cells. FR-targeted liposomes containing docetaxel showed 4.4-fold greater cytotoxicity compared to non-targeted liposomes in KB cells. Plasma clearance profiles of FR-targeted and non-targeted liposomeal docetaxel were evaluated and compared with that of docetaxel in Tween 80/ethanol formulation. The liposomal formulations showed much longer terminal half lives (4.92 h and 6.75 h for FR-targeted and non-targeted, respectively) than docetaxel in Tween 80/ethanol solution (1.09 h). FR-targeted liposomes are promising tumor cell-selective nanocarriers for docetaxel with potential for therapeutic applications. PMID:19435095

Zhai, Guangxi; Wu, Jun; Xiang, Guangya; Mao, Wenxue; Yu, Bo; Li, Hong; Piao, Longzhu; Lee, L. James



Guidelines for the diagnosis and treatment of cobalamin and folate disorders.  


The clinical picture is the most important factor in assessing the significance of test results assessing cobalamin status because there is no 'gold standard' test to define deficiency. Serum cobalamin currently remains the first-line test, with additional second-line plasma methylmalonic acid to help clarify uncertainties of underlying biochemical/functional deficiencies. Serum holotranscobalamin has the potential as a first-line test, but an indeterminate 'grey area' may still exist. Plasma homocysteine may be helpful as a second-line test, but is less specific than methylmalonic acid. The availability of these second-line tests is currently limited. Definitive cut-off points to define clinical and subclinical deficiency states are not possible, given the variety of methodologies used and technical issues, and local reference ranges should be established. In the presence of discordance between the test result and strong clinical features of deficiency, treatment should not be delayed to avoid neurological impairment. Treatment of cobalamin deficiency is recommended in line with the British National Formulary. Oral therapy may be suitable and acceptable provided appropriate doses are taken and compliance is not an issue. Serum folate offers equivalent diagnostic capability to red cell folate and is the first-line test of choice to assess folate status. PMID:24942828

Devalia, Vinod; Hamilton, Malcolm S; Molloy, Anne M



Tumor imaging using P866, a high-relaxivity gadolinium chelate designed for folate receptor targeting.  


The objective of this study was to evaluate the potential of a high-relaxivity macromolecular gadolinium (Gd) chelate to target folate receptors (FRs). P866 is a dimeric high-relaxivity Gd chelate coupled to a folate moiety. Binding affinity, in vivo biodistribution studies in KB tumor-bearing mice at 1, 4, and 24 h, and dynamic contrast-enhanced (DCE)-MRI (2.35 T) over 4 h were assessed. Binding and internalization of P866 through the FR was demonstrated. Due to the high molecular volume of P866, the binding affinity compared to free FA was decreased (K(D) = 59.3 +/- 1.8 nM and 5.9 +/- 0.2 nM, respectively). Tumor/muscle (T/M) uptake was 5.4 +/- 1.0, 4 h after injection of 15 micromol/kg. Competition with free FA was less effective when the dose was increased due to a saturation of FR. At a dose of 5 micromol/kg, a 70% difference in signal enhancement was observed between P866 and the nonspecific reference compound, thus demonstrating the specificity of FR targeting. While this high-relaxivity folate-Gd chelate has demonstrated its potential capacity to target in vivo FR on tumors, the sensitivity is probably limited to a certain extent by the saturation of the FR and by the decrease in the apparent relaxivity of the internalized part of P866 in the tumor cells. PMID:19025883

Corot, Claire; Robert, Philippe; Lancelot, Eric; Prigent, Philippe; Ballet, Sébastien; Guilbert, Irène; Raynaud, Jean-Sébastien; Raynal, Isabelle; Port, Marc



Interaction of methotrexate, folates, and pyridine nucleotides with dihydrofolate reductase: calorimetric and spectroscopic binding studies.  

PubMed Central

The thermodynamic parameters, deltaG, deltaH, and deltaS characterizing the tight binding of methotrexate, folates, and pyridine nucleotides to chicken liver dihydrofolate reductase (5,6,7,8-tetrahydrofolate: NADP+ oxidoreductase, EC have been determined from calorimetric and fluorescence measurements. At 25 degrees the binding of NADPH and NADP+ is characterized by small negative enthalpies and large positive entropies whereas the binding of the folates and methotrexate is accompanied by large negative enthalpies and small negative entropies. In addition, the enthalpy of methotrexate-enzyme interaction demonstrates a proton transfer associated with binding; this is not the case with folate and dihydrofolate, thus confirming the conclusions drawn from the observed difference spectra characteristic of the interaction of methotrexate and substrates with the enzyme. The implications of these results are discussed in terms of the nature of the binding process, conformational changes in the enzyme, and the nature of the active site region. PMID:28523

Subramanian, S; Kaufman, B T



Association between Selected Folate Pathway Polymorphisms and Nonsyndromic Limb Reduction Defects: A Case-Parental Analysis  

PubMed Central

SUMMARY Inadequate folate status due to either genetic variation or nutritional deficiencies has been associated with an increased risk of congenital malformations including orofacial clefting, limb, cardiac and neural tube defects. Few epidemiologic studies have examined the association between limb reduction defects (LRDs) and folate-related genetic polymorphisms other than MTHFR 677C?T. We conducted a case–parental analysis of 148 families who participated in the National Birth Defects Prevention Study (NBDPS) to examine the association between nonsyndromic transverse and longitudinal LRDs with five single nucleotide polymorphisms (SNPs) in genes encoding for enzymes in folate and methionine pathways. Log-linear Poisson regression, adapted for analysis of case–parental data, assuming an additive genetic model was used to estimate genetic relative risks and 95% confidence intervals for the association between LRDs and each SNP. Among women who did not take multivitamin supplements, the MTHFR 677T variant acts via the offspring’s genome to increase the risk of LRDs. No association between LRDs and any fetal SNP was found among women who used multivitamin supplements. These results suggest the possibility that initiating folic acid supplementation prior to pregnancy may reduce the risk of having a LRD-affected pregnancy, especially in women whose offspring inherit one or two copies of the MTHFR 677T variant. PMID:21281325

Cleves, Mario A.; Hobbs, Charlotte A.; Zhao, Weizhi; Krakowiak, Patrycja A.; MacLeod, Stewart L.



Synthesis of folate-conjugated amphiphiles for tumor-targeted drug delivery.  


Folic acid was derivatized specifically at its gamma-carboxyl group to retain its ligand-binding activity to the folate receptor alpha (FRalpha) present on HeLa cells. Amphiphilic molecules labeled with folic acid were prepared by conjugation of long-chain primary amines directly or via diamine linkers to the gamma-carboxyl group of folic acid. Folic acid amphiphiles labeled with fluorescent 7-amino-4-carbamoylmethylcoumarin (ACC) were also prepared to visualize the uptake of amphiphiles in folate receptor positive cells. The structures of the new compounds were verified by proton NMR and MALDI-TOF mass spectrometry. The amphiphiles form micelles in water. Critical micelle concentrations (CMCs) were determined by the pyrene fluorescence method for folic acid amphiphiles and the rise in capillary height method for the fluorescently labeled amphiphile. The CMCs of the amphiphiles were studied in buffer solution at pH 8 and ranged from 2 to 64 microM. The formation of micelle increased the solubility of paclitaxel, a model lipophilic anticancer compound, by more than 80%. A significant amount of the fluorescently tagged amphiphile was internalized into HeLa cells known to express FRsalpha when compared with Caco-2 cells that do not express FRalpha. Therefore, folate-labeled amphiphiles show promise in targeting antitumor agents to FRalpha-expressing cancer cells. PMID:18985509

Bhattacharya, Shiladitya; Franz, Andreas; Li, Xiaoling; Jasti, Bhaskara



Sterols of the fungi - Distribution and biosynthesis.  

NASA Technical Reports Server (NTRS)

The importance of sterols in the growth and reproduction in fungi is becoming increasingly apparent. This article concerns the composition and biosynthesis of ergosterol in these organisms. Comparison to plant and animal sterol formation are made.

Weete, J. D.



Accessing Natural Products by Combinatorial Biosynthesis  

NSDL National Science Digital Library

Enhancement and selective production of the protein phosphatase IIa inhibitor phoslactomycin (PLM) B by rational engineering of the PLM biosynthetic pathway highlights the effectiveness of combinatorial biosynthesis as a promising way to prepare complex natural products and their analogs.

Ben Shen (University of Wisconsin-Madison;Division of Pharmaceutical Sciences and Department of Chemistry REV)



Lipid biosynthesis in cultures of oilseed rape  

Microsoft Academic Search

Summary  This review focuses on how microspore-derived (MD) embros and cell suspension cultures of oilseed rape have been used to advance\\u000a our understanding of the biochemistry and molecular biology of lipid biosynthesis in plants. Both types of cultures are easily\\u000a maintained and circumvent the difficulties associated with using developing seeds for investigations of lipid biosynthesis.\\u000a Developing MD embryos exhibit a similar

Randall J. Weselake



Knocking out salicylate biosynthesis genes in Mycobacterium smegmatis induces hypersensitivity to p-aminosalicylate (PAS).  


Because of the emergence of strains of Mycobacterium tuberculosis resistant to first-line antituberculosis agents, one of the second-line drugs, p-aminosalicylate (PAS), has regained importance in the treatment of tuberculosis. The mode of action of PAS, however, remains controversial as to whether it inhibits mycobactin or folate biosynthesis. To unravel this, we have studied the effect of PAS on wild-type Mycobacterium smegmatis and its mutants (gene knockouts of the salicylate pathway -trpE2, entC and entD). The wild type had no sensitivity to PAS (MIC>400 ?g mL(-1) ), whereas the mutants were hypersensitive, with 1 ?g mL(-1) inhibiting growth. The sulphonamides, trimethoprim and dapsone, had little effect on the growth of either the mutants or the wild type. In addition, PAS at 0.5 ?g mL(-1) increased the accumulation of salicylate with the wild type and mutants. These results support our hypothesis that PAS targets the conversion of salicylate to mycobactin, thus preventing iron acquisition from the host. PMID:20735479

Nagachar, Nivedita; Ratledge, Colin



Application of stable isotope dilution assays based on liquid chromatography-tandem mass spectrometry for the assessment of folate bioavailability.  


A pilot study was performed to prove the suitability of stable isotope dilution assays for assessing the bioavailability of endogenous folates in foods. By using [2H(4)]folic acid, [2H(4)]tetrahydrofolate, [2H(4)]5-methyltetrahydrofolate, [2H(4)]5-formyltetrahydrofolate and [2H(4)]10-formylfolic acid as internal standards, folates in spinach, apple juice and blood plasma were quantified by liquid chromatography coupled to tandem mass spectrometry. To liberate the pteroyl monoglutamates, sample extracts of foods were treated by rat plasma. Sample clean-up was achieved by solid-phase extraction on anion-exchange cartridges, which proved to be sufficient to obtain mass chromatograms devoid of matrix interferences. The bioavailability study was designed as a short-time protocol with three meals, the first consisting of 600 g spinach (meal A), the second consisting of 600 g apple sauce with additionally 400 microg synthetic folic acid (meal B) and the third consisting solely of 600 g apple sauce (meal C). Prior to the meals, the participating volunteer's tissue was saturated with folates to achieve a significant response of plasma folate to the meals. After consumption of meals A and B a significant rise in folate plasma level compared to meal C (mean level at 28 microg/ml) was observed. The relative bioavailability of folate following meal A exceeded significantly the suggested value of 50% for food folates by taking the dose-normalized area under the curve (AUC) following ingestion of meal B as reference. PMID:12860024

Rychlik, Michael; Netzel, Michael; Pfannebecker, Inga; Frank, Thomas; Bitsch, Irmgard



Deficiencies of the Microelements, Folate and Vitamin B12 in Women of the Child Bearing Ages in Gorgan, Northern Iran  

PubMed Central

Background: The deficiencies of folic acid, vitamin B12, and microelements during pregnancy may affect the health of newborns. Objectives: To assess the serum levels of folate, vitamin B12, iron, zinc and copper in healthy women of the childbearing ages in Gorgan, northern Iran. Methodology: This descriptive, cross-sectional study was carried out on 100 women of childbearing ages in northern Iran during November 2007-March 2008. The serum levels of folate, vitamin B12, iron, copper and zinc were evaluated by laboratory tests. Results: Iron, copper , folate, vitamin B12 deficiencies and folate with vitamin B12 deficiency were detected in 13%, 32% , 13% , 32% and 11% women of the childbearing ages, respectively . According to the ethnicity, vitamin B12, folate and iron deficiencies in the Sistani group were observed in 38.3%, 12.9% and 12.9% of the women, respectively. In the native Fars group, the above mentioned deficiencies were found in 31.1%, 13.4% and 7.5% of the subjects. Folate and vitamin B12 deficiencies were observed in the urban habitant in 32.7% and 11.5 % of the subjects as compared to those in the rural habitant (in 30.4% and 15.2%of the subjects respectively). The folate deficiencies in the under and above 18 years old subjects were 22.2% and 9.9%, respectively. Conclusions: This study showed that the deficiency of the micronutrients was considerable in women of the childbearing ages in Gorgan, northern Iran. PMID:23905113

Sedehi, Maliheh; Behnampour, Naser; Golalipour, Mohammad Jafar



Association between dietary intake of folate, vitamin B6, B12 & MTHFR, MTR Genotype and breast cancer risk  

PubMed Central

Objective: we conducted a case-control study to investigate the association between dietary folate, vitamin B6 and vitamin B12 intake, MTHFR and MTR genotype, and breast cancer risk. Methods: Genotyping for MTHFR C677T and A1298C and MTR A2756G polymorphisms were performed using polymerase chain reaction-restriction fragment length polymorphism analysis (PCR-RFLP) method. The intake of folate, vitamin B6 and vitamin B12 were calculated by each food item from questionnaire. Results: Subjects with breast cancer tended to have more first-degree relatives (?2=30.77, P<0.001) and have high intake of folate (t=2.42, P=0.008) and Vitamin B6 (t=2.94, P=0.002). Compared to the reference group, women with MTHFR 677 TT genotype and T allele had a significantly increased risk of breast cancer, with ORs (95%CI) of 1.8(1.08-2.27) and 1.39(1.02-1.92), respectively. For those who had folate intake?450 ug/day, MTHFR 667TT genotype was associated with a higher risk of breast cancer (OR=2.45, 95% CI=1.09-5.82, P=0.02). Similarly, subjects with Vitamin B6 intake?0.84 mg/day and MTHFR 667T allele genotype was correlated with a marginally increased risk of breast cancer. A significant interaction was observed between MTHFR C667T polymorphism and folate intake on the risk of breast cancer (P for interaction was 0.025). Conclusion: This case-control study found a significant association between MTHFR C667T polymorphism, folate intake and vitamin B6 and breast cancer risk, and a significant interaction was observed between MTHFR C667T polymorphism and folate intake on the risk of breast cancer. PMID:24639841

Weiwei, Zheng; Liping, Chen; Dequan, Li



Homocysteine, Cobalamin and Folate Status and their Relations to Neurocognitive and Psychological Markers in Elderly in Northeasten of Iran  

PubMed Central

Objective(s): Incidence of neurocognitive and psychological disorders may be related to serum homocystein (Hcy), cobalamin (vitamin B12) and folate levels in old people. The aim of this study was to assess the relation between Hcy, cobalamin, folate and neurocognitive and/or psychological disorders in the elderly. Materials and Methods: In this cross-sectional study, 280 subjects with ? 65 years old ,were evaluated. The subjects were selected from 12 regions of Mashhad, Iran, over March to October 2009. After blood sampling, data were collected by questionnaire, face to face interview and performing neurocognitive and psychological tests. The sera of 250 persons were analyzed for cobalamin and folate by RIA method. Amongst the aforementioned samples, 78 cases with cobalamin <300 pg/ml and folate <6.5 ng/ml were analyzed for Hcy by ELISA method. Results: Amongst the people, 126 (45%) were male and 154 (55%) were female. The prevalence of hyperhomocysteinemia (HHcy) was 59.5% and 37.1% in male and female respectively (P -value =0.049). Hcy inversely correlated to cobalamin (r=-0.282, P=0.014) and to folate (r=-0.203, P=0.014). Hcy, cobalamin and folate correlations to neurocognitive and psychological impairments were not statically significant. Conclusion: Hyper Hcy or low cobalamin and folate in the elderly, are prevalent but their relationships with neurocognitive and psychological impairments is controversial. If these relationships had been confirmed, performing a single serum Hcy or cobalamin test would have been enough enough to diagnose and prevent neurocognitive impairments and inversely, neurocognitive-psychological sign and symptoms could have meant probable tissue vitamin deficiencies. However methods of assessing neurocognitive and psychological markers with validity and reliability of clinical and laboratory tests for finding aforementioned relationships should be revised. PMID:23997903

Manavifar, Lida; Nemati Karimooy, Habibollah; Jamali, jamshid; Talebi doluee, Morteza; Shirdel, Abbas; Nejat shokohi, Amireh; Fatemi nayyeri, Mahdie



Gene Variants in the Folate-mediated One-carbon Metabolism (FOCM) Pathway as Risk Factors for Conotruncal Heart Defects  

PubMed Central

We evaluated 35 variants among four folate-mediated one-carbon metabolism pathway genes, MTHFD1, SHMT1, MTHFR, and DHFR as risk factors for conotruncal heart defects. Cases with a diagnosis of single gene disorders or chromosomal aneusomies were excluded. Controls were randomly selected from area hospitals in proportion to their contribution to the total population of live-born infants. Odds Ratios (OR) and the 95% confidence intervals were computed for each genotype (homozygous variant or heterozygote, versus homozygous wildtype) and for increase of each less common allele (log-additive model). Interactions between each variant and three folate intake variables (maternal multivitamin use, maternal dietary folate intake, and combined maternal folate intake) were also evaluated under the log-additive model. In general, we did not identify notable associations. The A allele of MTHFD1 rs11627387 was associated with a 1.7-fold increase in conotruncal defects risk in both Hispanic mothers (OR=1.7, 95% CI=1.1?2.5) and Hispanic infants (OR=1.7, 95% CI=1.2?2.3). The T allele of MTHFR rs1801133 was associated with a 2.8-fold increase of risk among Hispanic women whose dietary folate intake was ? 25th centile. The C allele of MTHFR rs1801131 was associated with a two-fold increase of risk (OR=2.0, 95%CI=1.0?3.9) only among those whose dietary folate intake was >25th centile. Our study suggested that MTHFD1 rs11627387 may be associated with risk of conotruncal defects through both maternal and offspring genotype effect among the Hispanics. Maternal functional variants in MTHFR gene may interact with dietary folate intake and modify the conotruncal defects risk in the offspring. PMID:22495907

Zhu, Huiping; Yang, Wei; Lu, Wei; Etheredge, Analee; Lammer, Edward J; Finnell, Richard; Carmichael, Suzan L.; Shaw, Gary



EE-drospirenone-levomefolate calcium versus EE-drospirenone + folic acid: folate status during 24 weeks of treatment and over 20 weeks following treatment cessation  

PubMed Central

Background Adequate folate supplementation in the periconceptional phase is recommended to reduce the risk of neural tube defects. Oral contraceptives may provide a reasonable delivery vehicle for folate supplementation before conception in women of childbearing potential. This study aimed to demonstrate that a fixed-dose combination of an oral contraceptive and levomefolate calcium leads to sustainable improvements in folate status compared with an oral contraceptive + folic acid. Methods This was a double-blind, randomized, parallel-group study in which 172 healthy women aged 18–40 years received ethinylestradiol (EE)-drospirenone-levomefolate calcium or EE-drospirenone + folic acid for 24 weeks (invasion phase), and EE-drospirenone for an additional 20 weeks (folate elimination phase). The main objective of the invasion phase was to examine the area under the folate concentration time-curve for plasma and red blood cell (RBC) folate, while the main objective of the elimination phase was to determine the duration of time for which RBC folate concentration remained ? 906 nmol/L after cessation of EE-drospirenone-levomefolate calcium. Results Mean concentration-time curves for plasma folate, RBC folate, and homocysteine were comparable between treatment groups during both study phases. During the invasion phase, plasma and RBC folate concentrations increased and approached steady-state after about 8 weeks (plasma) or 24 weeks (RBC). After cessation of treatment with levomefolate calcium, folate concentrations decreased slowly. The median time to RBC folate concentrations falling below 906 nmol/L was 10 weeks (95% confidence interval 8–12 weeks) after cessation of EE-drospirenone-levomefolate calcium treatment. Plasma and RBC folate levels remained above baseline values in 41.3% and 89.3% of women, respectively, at the end of the 20-week elimination phase. Conclusion Improvements in folate status were comparable between EE-drospirenone-levomefolate calcium and EE-drospirenone + folic acid. Plasma and RBC folate levels remained elevated for several months following cessation of treatment with EE-drospirenone-levomefolate calcium. PMID:23610531

Diefenbach, Konstanze; Trummer, Dietmar; Ebert, Frank; Lissy, Michael; Koch, Manuela; Rohde, Beate; Blode, Hartmut



Hereditary folate malabsorption: A positively charged amino acid at position 113 of the proton-coupled folate transporter (PCFT/SLC46A1) is required for folic acid binding  

SciTech Connect

The proton-coupled folate transporter (PCFT/SLC46A1) mediates intestinal folate uptake at acidic pH. Some loss of folic acid (FA) transport mutations in PCFT from hereditary folate malabsorption (HFM) patients cluster in R113, thereby suggesting a functional role for this residue. Herein, unlike non-conservative substitutions, an R113H mutant displayed 80-fold increase in the FA transport Km while retaining parental Vmax, hence indicating a major fall in folate substrate affinity. Furthermore, consistent with the preservation of 9% of parental transport activity, R113H transfectants displayed a substantial decrease in the FA growth requirement relative to mock transfectants. Homology modeling based on the crystal structures of the Escherichia coli transporter homologues EmrD and glycerol-3-phosphate transporter revealed that the R113H rotamer properly protrudes into the cytoplasmic face of the minor cleft normally occupied by R113. These findings constitute the first demonstration that a basic amino acid at position 113 is required for folate substrate binding.

Lasry, Inbal; Berman, Bluma [The Fred Wyszkowski Cancer Research Laboratory, Dept. of Biology, Technion-Israel Institute of Technology, Haifa 32000 (Israel)] [The Fred Wyszkowski Cancer Research Laboratory, Dept. of Biology, Technion-Israel Institute of Technology, Haifa 32000 (Israel); Glaser, Fabian [Bioinformatics Knowledge Unit, The Lorry I. Lokey Interdisciplinary Center for Life Sciences and Engineering, Technion, Haifa 32000 (Israel)] [Bioinformatics Knowledge Unit, The Lorry I. Lokey Interdisciplinary Center for Life Sciences and Engineering, Technion, Haifa 32000 (Israel); Jansen, Gerrit [Department of Rheumatology, VU University Medical Center, Amsterdam (Netherlands)] [Department of Rheumatology, VU University Medical Center, Amsterdam (Netherlands); Assaraf, Yehuda G., E-mail: [The Fred Wyszkowski Cancer Research Laboratory, Dept. of Biology, Technion-Israel Institute of Technology, Haifa 32000 (Israel)



Salicylic Acid Biosynthesis and Metabolism  

PubMed Central

Salicylic acid (SA) has been shown to regulate various aspects of growth and development; it also serves as a critical signal for activating disease resistance in Arabidopsis thaliana and other plant species. This review surveys the mechanisms involved in the biosynthesis and metabolism of this critical plant hormone. While a complete biosynthetic route has yet to be established, stressed Arabidopsis appear to synthesize SA primarily via an isochorismate-utilizing pathway in the chloroplast. A distinct pathway utilizing phenylalanine as the substrate also may contribute to SA accumulation, although to a much lesser extent. Once synthesized, free SA levels can be regulated by a variety of chemical modifications. Many of these modifications inactivate SA; however, some confer novel properties that may aid in long distance SA transport or the activation of stress responses complementary to those induced by free SA. In addition, a number of factors that directly or indirectly regulate the expression of SA biosynthetic genes or that influence the rate of SA catabolism have been identified. An integrated model, encompassing current knowledge of SA metabolism in Arabidopsis, as well as the influence other plant hormones exert on SA metabolism, is presented. PMID:22303280

Dempsey, D'Maris Amick; Vlot, A. Corina; Wildermuth, Mary C.; Klessig, Daniel F.



Biosynthesis of trichothecenes and apotrichothecenes.  


Fusarium culmorum produces two major trichothecenes, 3-acetyldeoxynivalenol and sambucinol, and some minor apotrichothecenes. It was desired to investigate if during their biosynthesis a C-11-keto intermediate was involved. To verify this postulate, trichodiene, a known precursor to trichothecenes, was synthesized with two deuteriums at C-11 and one at C-15. It was then fed to F. culmorum cultures, and the derived metabolites were purified and analyzed. The results ruled out the involvement of an 11-keto intermediate but revealed two novel apotrichothecenes. The characterization of their structures suggested that one of the 2-hydroxy-11alpha-apotrichothecene stereoisomers (2alpha or 2beta) could be converted to sambucinol. These apotrichothecenes were therefore synthesized labeled specifically with two deuteriums at C-4 and C-15 and fed to F. culmorum cultures. Indeed, the result established for the first time that 2alpha-hydroxy-11alpha-apotrichothecene was a precursor to sambucinol. A biosynthetic scheme for the production of trichothecenes and apotrichothecenes is described. PMID:10552458

Zamir, L O; Nikolakakis, A; Sauriol, F; Mamer, O



Gibberellin biosynthesis and its regulation.  


The GAs (gibberellins) comprise a large group of diterpenoid carboxylic acids that are ubiquitous in higher plants, in which certain members function as endogenous growth regulators, promoting organ expansion and developmental changes. These compounds are also produced by some species of lower plants, fungi and bacteria, although, in contrast to higher plants, the function of GAs in these organisms has only recently been investigated and is still unclear. In higher plants, GAs are synthesized by the action of terpene cyclases, cytochrome P450 mono-oxygenases and 2-oxoglutarate-dependent dioxygenases localized, respectively, in plastids, the endomembrane system and the cytosol. The concentration of biologically active GAs at their sites of action is tightly regulated and is moderated by numerous developmental and environmental cues. Recent research has focused on regulatory mechanisms, acting primarily on expression of the genes that encode the dioxygenases involved in biosynthesis and deactivation. The present review discusses the current state of knowledge on GA metabolism with particular emphasis on regulation, including the complex mechanisms for the maintenance of GA homoeostasis. PMID:22533671

Hedden, Peter; Thomas, Stephen G



Uptake of Etoposide in CT-26 Cells of Colorectal Cancer Using Folate Targeted Dextran Stearate Polymeric Micelles  

PubMed Central

Targeted drug delivery using folate receptors is one of the most interesting chemotherapeutic research areas over the past few years. A novel folate targeted copolymer was synthesized using dextran stearate coupled to folic acid. FT-IR and NMR spectroscopy were used to confirm successful conjugation. Micelles prepared using this copolymer were characterized for their particle size, zeta potential, critical micelle concentration (CMC), drug loading capacity, and release efficiency. Cytotoxicity and cellular uptake of the micelles were estimated using CT-26 colorectal carcinoma cell line. FT-IR and NMR spectroscopy confirmed production of folate grafted dextran stearate copolymer. Low CMC value indicates that the copolymers are suitable for preparation of stable micelles useful in parenteral dosage forms. Particle size and zeta potential of the targeted nanoparticles were 105.5 ± 2.0?nm and ?21.2?mV, respectively. IC50 of etoposide loaded in folate grafted dextran stearate enhanced about 20-fold compared to the pure drug (0.49 ± 0.11??g/mL versus 9.41 ± 0.52??g/mL). It seems that etoposide loaded in micelles of folate grafted dextran stearate copolymer is promising in reducing drug resistance of colorectal cancer by boosting etoposide cellular uptake. PMID:24689050

Varshosaz, Jaleh; Hassanzadeh, Farshid; Sadeghi-Aliabadi, Hojjat; Firozian, Farzin



Uptake of etoposide in CT-26 cells of colorectal cancer using folate targeted dextran stearate polymeric micelles.  


Targeted drug delivery using folate receptors is one of the most interesting chemotherapeutic research areas over the past few years. A novel folate targeted copolymer was synthesized using dextran stearate coupled to folic acid. FT-IR and NMR spectroscopy were used to confirm successful conjugation. Micelles prepared using this copolymer were characterized for their particle size, zeta potential, critical micelle concentration (CMC), drug loading capacity, and release efficiency. Cytotoxicity and cellular uptake of the micelles were estimated using CT-26 colorectal carcinoma cell line. FT-IR and NMR spectroscopy confirmed production of folate grafted dextran stearate copolymer. Low CMC value indicates that the copolymers are suitable for preparation of stable micelles useful in parenteral dosage forms. Particle size and zeta potential of the targeted nanoparticles were 105.5 ± 2.0 nm and -21.2 mV, respectively. IC50 of etoposide loaded in folate grafted dextran stearate enhanced about 20-fold compared to the pure drug (0.49 ± 0.11 ?g/mL versus 9.41 ± 0.52 ?g/mL). It seems that etoposide loaded in micelles of folate grafted dextran stearate copolymer is promising in reducing drug resistance of colorectal cancer by boosting etoposide cellular uptake. PMID:24689050

Varshosaz, Jaleh; Hassanzadeh, Farshid; Sadeghi-Aliabadi, Hojjat; Firozian, Farzin



Folate Intake, MTHFR Polymorphisms, and the Risk of Colorectal Cancer: A Systematic Review and Meta-Analysis  

PubMed Central

Background. The objective was to determine whether relationships exist between the methylene-tetrahydrofolate reductase (MTHFR) polymorphisms and risk of colorectal cancer (CRC) and examine whether the risk is modified by level of folate intake. Methods. MEDLINE, Embase, and SCOPUS were searched to May 2012 using the terms “folic acid,” “folate,” “colorectal cancer,” “methylenetetrahydrofolate reductase,” “MTHFR.” Observational studies were included which (1) assessed the risk of CRC for each polymorphism and/or (2) had defined levels of folate intake for each polymorphism and assessed the risk of CRC. Results. From 910 references, 67 studies met our criteria; hand searching yielded 10 studies. The summary risk estimate comparing the 677CT versus CC genotype was 1.02 (95% CI 0.95–1.10) and for 677TT versus CC was 0.88 (95% CI 0.80–0.96) both with heterogeneity. The summary risk estimates for A1298C polymorphisms suggested no reduced risk. The summary risk estimate for high versus low total folate for the 677CC genotype was 0.70 (95% CI 0.56–0.89) and the 677TT genotype 0.63 (95% CI 0.41–0.97). Conclusion. These results suggest that the 677TT genotype is associated with a reduced risk of developing CRC, under conditions of high total folate intake, and this associated risk remains reduced for both MTHFR 677 CC and TT genotypes. PMID:23125859

Kennedy, Deborah A.; Stern, Seth J.; Matok, Ilan; Moretti, Myla E.; Sarkar, Moumita; Adams-Webber, Thomasin; Koren, Gideon



Adverse effect of metformin therapy on serum vitamin B12 and folate: short-term treatment causes disadvantages?  


Diabetes is a global public health challenge that imposes heavy burdens on communities and individuals. Metformin, the first-line medication for diabetes, has the superiority of reducing risk of macrovascular diseases, all-cause mortality and even possibly cancers. Recent observational studies, however, have demonstrated that long-term metformin therapy increases the probability of vitamin B12 and folate deficiency, and might contribute to the progression of diabetic peripheral neuropathy. Despite metformin is widely used and extensively studied, randomized controlled trials performed to explore the effects of metformin on vitamin B12 and folate are limited. Besides, whether short-term treatment causes vitamin deficiency is a pending issue. We postulate that even a few-month treatment with metformin results in the decrease of vitamin B12 and folate. However, supplementation of vitamin B12 rather than the combination of vitamin B12 and folate might be profitable based on the mechanism of metformin on vitamins in patients with type 2 diabetes. This viewpoint differs from those of majority that a combined supplementation of vitamin B12 and folate is inclined to be advised. PMID:23751310

Xu, Lijuan; Huang, Zhimin; He, Xiaoying; Wan, Xuesi; Fang, Donghong; Li, Yanbing



Efficiency of Lignin Biosynthesis: a Quantitative Analysis  

PubMed Central

Lignin is derived mainly from three alcohol monomers: p?coumaryl alcohol, coniferyl alcohol and sinapyl alcohol. Biochemical reactions probably responsible for synthesizing these three monomers from sucrose, and then polymerizing the monomers into lignin, were analysed to estimate the amount of sucrose required to produce a unit of lignin. Included in the calculations were amounts of respiration required to provide NADPH (from NADP+) and ATP (from ADP) for lignin biosynthesis. Two pathways in the middle stage of monomer biosynthesis were considered: one via tyrosine (found in monocots) and the other via phenylalanine (found in all plants). If lignin biosynthesis proceeds with high efficiency via tyrosine, 76·9, 70·4 and 64·3 % of the carbon in sucrose can be retained in the fraction of lignin derived from p?coumaryl alcohol, coniferyl alcohol and sinapyl alcohol, respectively. The corresponding carbon retention values for lignin biosynthesis via phenylalanine are less, at 73·2, 65·7 and 60·7 %, respectively. Energy (i.e. heat of combustion) retention during lignin biosynthesis via tyrosine could be as high as 81·6, 74·5 and 67·8 % for lignin derived from p?coumaryl alcohol, coniferyl alcohol and sinapyl alcohol, respectively, with the corresponding potential energy retention values for lignin biosynthesis via phenylalanine being less, at 77·7, 69·5 and 63·9 %, respectively. Whether maximum efficiency occurs in situ is unclear, but these values are targets that can be considered in: (1) plant breeding programmes aimed at maximizing carbon or energy retention from photosynthate; (2) analyses of (minimum) metabolic costs of responding to environmental change or pest attack involving increased lignin biosynthesis; (3) understanding costs of lignification in older tissues; and (4) interpreting carbon balance measurements of organs and plants with large lignin concentrations. PMID:12714366




Sustained Homocysteine-Lowering Effect over Time of Folic Acid-Based Multivitamin Therapy in Stroke Patients despite Increasing Folate Status in the Population  

Microsoft Academic Search

Background and Aims: It is uncertain what impact increasing voluntary folate fortification may be having on the statistical power of randomized trials testing the homocysteine hypothesis of atherothrombosis. The objective of this study was to determine whether there has been a change in folate status between 1998 and 2002 in stroke patients randomized into the VITAmins TO Prevent Stroke (VITATOPS)

G. J. Hankey; J. W. Eikelboom; K. Loh; M. Tang; J. Pizzi; J. Thom; Q. Yi



Dietary folate intake in combination with MTHFR C677T genotype and promoter methylation of tumor suppressor and DNA repair genes in sporadic colorectal adenomas  

Microsoft Academic Search

Methylation of the promoter region of tumor suppressor genes is increasingly recognized to play a role in cancer development through silencing of gene transcription. We examined the associations between dietary folate intake, MTHFR C677T genotype, and promoter methylation of six tumor suppressor and DNA repair genes. Patients with colorectal adenoma (n = 149) and controls (n = 286) with folate

M. van den Donk; M. van Engeland; E. P. M. Pellis; B. J. M. Witteman; F. J. Kok; J. Keijer; E. Kampman



The impact of folate deficiency on the base excision repair pathway: Analysis of enzyme coordination in response to DNA damage and imbalanced repair  

Microsoft Academic Search

The condition of folate deficiency has been implicated in carcinogenesis, with the strongest evidence formulated in colon cancer. The role of folate in DNA repair, DNA synthesis and methylation reactions renders this nutrient an valuable target for studying the onset and progression of cancer. Using molecular techniques to determine gene and protein expression, enzyme activity and methylation status elucidates the

Amanda B Pilling



The impact of folate deficiency on the base excision repair pathway: Analysis of enzyme coordination in response to dna damage and imbalanced repair  

Microsoft Academic Search

The condition of folate deficiency has been implicated in carcinogenesis, with the strongest evidence formulated in colon cancer. The role of folate in DNA repair, DNA synthesis and methylation reactions renders this nutrient an valuable target for studying the onset and progression of cancer. Using molecular techniques to determine gene and protein expression, enzyme activity and methylation status elucidates the

Amanda Pilling




EPA Science Inventory

Folate and folic acid are forms of the B vitamin that are involved in the synthesis, repair and functioning of DNA and are required for the production and maintenance of cells. Low levels of folate have been associated with several forms of cancer, including colon cancer. Aberran...


The methylenetetrahydrofolate reductase 677TT genotype and folate intake interact to lower global leukocyte DNA methylation in young Mexican American women  

Microsoft Academic Search

DNA methylation is an epigenetic feature associated with X chromosome inactivation, genomic imprinting, transcriptional silencing of genes, and genomic stability. Folate provides a labile source of methyl groups that may be used for cellular methylation reactions, including DNA methylation. The methylenetetrahydrofolate reductase (MTHFR) 677C?T variant is an important determinant of folate nutriture and may influence DNA methylation. This study sought

Juan Axume; Steven S. Smith; Igor P. Pogribny; David J. Moriarty; Marie A. Caudill



Mitochondrial respiration without ubiquinone biosynthesis.  


Ubiquinone (UQ), a.k.a. coenzyme Q, is a redox-active lipid that participates in several cellular processes, in particular mitochondrial electron transport. Primary UQ deficiency is a rare but severely debilitating condition. Mclk1 (a.k.a. Coq7) encodes a conserved mitochondrial enzyme that is necessary for UQ biosynthesis. We engineered conditional Mclk1 knockout models to study pathogenic effects of UQ deficiency and to assess potential therapeutic agents for the treatment of UQ deficiencies. We found that Mclk1 knockout cells are viable in the total absence of UQ. The UQ biosynthetic precursor DMQ9 accumulates in these cells and can sustain mitochondrial respiration, albeit inefficiently. We demonstrated that efficient rescue of the respiratory deficiency in UQ-deficient cells by UQ analogues is side chain length dependent, and that classical UQ analogues with alkyl side chains such as idebenone and decylUQ are inefficient in comparison with analogues with isoprenoid side chains. Furthermore, Vitamin K2, which has an isoprenoid side chain, and has been proposed to be a mitochondrial electron carrier, had no efficacy on UQ-deficient mouse cells. In our model with liver-specific loss of Mclk1, a large depletion of UQ in hepatocytes caused only a mild impairment of respiratory chain function and no gross abnormalities. In conjunction with previous findings, this surprisingly small effect of UQ depletion indicates a nonlinear dependence of mitochondrial respiratory capacity on UQ content. With this model, we also showed that diet-derived UQ10 is able to functionally rescue the electron transport deficit due to severe endogenous UQ deficiency in the liver, an organ capable of absorbing exogenous UQ. PMID:23847050

Wang, Ying; Hekimi, Siegfried



Light-controlled flavonoid biosynthesis in fruits  

PubMed Central

Light is one of the most important environmental factors affecting flavonoid biosynthesis in plants. The absolute dependency of light to the plant development has driven evolvement of sophisticated mechanisms to sense and transduce multiple aspects of the light signal. Light effects can be categorized in photoperiod (duration), intensity (quantity), direction and quality (wavelength) including UV-light. Recently, new information has been achieved on the regulation of light-controlled flavonoid biosynthesis in fruits, in which flavonoids have a major contribution on quality. This review focuses on the effects of the different light conditions on the control of flavonoid biosynthesis in fruit producing plants. An overview of the currently known mechanisms of the light-controlled flavonoid accumulation is provided. R2R3 MYB transcription factors are known to regulate by differential expression the biosynthesis of distinct flavonoids in response to specific light wavelengths. Despite recent advances, many gaps remain to be understood in the mechanisms of the transduction pathway of light-controlled flavonoid biosynthesis. A better knowledge on these regulatory mechanisms is likely to be useful for breeding programs aiming to modify fruit flavonoid pattern.

Zoratti, Laura; Karppinen, Katja; Luengo Escobar, Ana; Haggman, Hely; Jaakola, Laura



Macrophage Folate Receptor-Targeted Antiretroviral Therapy Facilitates Drug Entry, Retention, Antiretroviral Activities and Biodistribution for Reduction of Human Immunodeficiency Virus Infections  

PubMed Central

Macrophages serve as vehicles for the carriage and delivery of polymer-coated nanoformulated antiretroviral therapy (nanoART). Although superior to native drug, high drug concentrations are required for viral inhibition. Herein, folate-modified atazanavir/ritonavir (ATV/r)-encased polymers facilitated macrophage receptor targeting for optimizing drug dosing. Folate coating of nanoART ATV/r significantly enhanced cell uptake, retention and antiretroviral activities without altering cell viability. Enhanced retentions of folate-coated nanoART within recycling endosomes provided a stable subcellular drug depot. Importantly, five-fold enhanced plasma and tissue drug levels followed folate-coated formulation injection in mice. Folate polymer encased ATV/r improves nanoART pharmacokinetics bringing the technology one step closer to human use. PMID:23680933

Puligujja, Pavan; McMillan, JoEllyn; Kendrick, Lindsey; Li, Tianyuzi; Balkundi, Shantanu; Smith, Nathan; Veerubhotla, Ram S.; Edagwa, Benson J.; Kabanov, Alexander V.; Bronich, Tatiana; Gendelman, Howard E.; Liu, Xin-Ming



{sup 13}C-enrichment at carbons 8 and 2 of uric acid after {sup 13}C-labeled folate dose in man  

SciTech Connect

To evaluate folate-dependent carbon incorporation into the purine ring, we measured {sup 13}C-enrichment independently at C{sub 2} and C{sub 8} of urinary uric acid (the final catabolite of purines) in a healthy male after an independent oral dose of [6RS]-5-[{sup 13}C]-formyltetrahydrofolate ([6RS]-5-H{sup 13}CO-H{sub 4}folate) or 10-H{sup 13}CO-7,8-dihydrofolate (10-H{sup 13}CO-H{sub 2}folate). The C{sub 2} position was {sup 13}C-enriched more than C{sub 8} after [6RS]-5-H{sup 13}CO-H{sub 4}folate, and C{sub 2} was exclusively enriched after 10-H{sup 13}CO-H{sub 2}folate. The enrichment of C{sub 2} was greater from [6RS]-5-H{sup 13}CO-H{sub 4}folate than 10-H{sup 13}CO-H{sub 2}folate using equimolar bioactive doses. Our data suggest that formyl C of [6RS]-10-H{sup 13}CO-H{sub 4}folate was not equally utilized by glycinamide ribotide transformylase (enriches C{sub 8}) and aminoimidazolecarboxamide ribotide (AICAR) transformylase (enriches C{sub 2}), and the formyl C of 10-H{sup 13}CO-H{sub 2}folate was exclusively used by AICAR transformylase. 10-HCO-H{sub 2}folate may function in vivo as the predominant substrate for AICAR transformylase in humans.

Baggott, Joseph E. [Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL 35294 (United States); Gorman, Gregory S. [Southern Research Institute, Birmingham, AL 35205 (United States); Morgan, Sarah L. [Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL 35294 (United States); Tamura, Tsunenobu [Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL 35294 (United States)]. E-mail:



The causal effect of red blood cell folate on genome-wide methylation in cord blood: a Mendelian randomization approach  

PubMed Central

Background Investigation of the biological mechanism by which folate acts to affect fetal development can inform appraisal of expected benefits and risk management. This research is ethically imperative given the ubiquity of folic acid fortified products in the US. Considering that folate is an essential component in the one-carbon metabolism pathway that provides methyl groups for DNA methylation, epigenetic modifications provide a putative molecular mechanism mediating the effect of folic acid supplementation on neonatal and pediatric outcomes. Results In this study we use a Mendelian Randomization Unnecessary approach to assess the effect of red blood cell (RBC) folate on genome-wide DNA methylation in cord blood. Site-specific CpG methylation within the proximal promoter regions of approximately 14,500 genes was analyzed using the Illumina Infinium Human Methylation27 Bead Chip for 50 infants from the Epigenetic Birth Cohort at Brigham and Women’s Hospital in Boston. Using methylenetetrahydrofolate reductase genotype as the instrument, the Mendelian Randomization approach identified 7 CpG loci with a significant (mostly positive) association between RBC folate and methylation level. Among the genes in closest proximity to this significant subset of CpG loci, several enriched biologic processes were involved in nucleic acid transport and metabolic processing. Compared to the standard ordinary least squares regression method, our estimates were demonstrated to be more robust to unmeasured confounding. Conclusions To the authors’ knowledge, this is the largest genome-wide analysis of the effects of folate on methylation pattern, and the first to employ Mendelian Randomization to assess the effects of an exposure on epigenetic modifications. These results can help guide future analyses of the causal effects of periconceptional folate levels on candidate pathways. PMID:24305512



Imaging peptidoglycan biosynthesis in Bacillus subtilis with fluorescent antibiotics  

E-print Network

Imaging peptidoglycan biosynthesis in Bacillus subtilis with fluorescent antibiotics Kittichoat that control the biosynthesis of this polymer. Here, we compare the staining patterns observed in Bacillus subtilis using fluorescent derivatives of two PG-binding antibiotics, vancomycin and ramoplanin

Rudner, David


Triterpenoid Biosynthesis and Engineering in Plants  

PubMed Central

Triterpenoid saponins are a diverse group of natural products in plants and are considered defensive compounds against pathogenic microbes and herbivores. Because of their various beneficial properties for humans, saponins are used in wide-ranging applications in addition to medicinally. Saponin biosynthesis involves three key enzymes: oxidosqualene cyclases, which construct the basic triterpenoid skeletons; cytochrome P450 monooxygenases, which mediate oxidations; and uridine diphosphate-dependent glycosyltransferases, which catalyze glycosylations. The discovery of genes committed to saponin biosynthesis is important for the stable supply and biotechnological application of these compounds. Here, we review the identified genes involved in triterpenoid biosynthesis, summarize the recent advances in the biotechnological production of useful plant terpenoids, and discuss the bioengineering of plant triterpenoids. PMID:22639586

Sawai, Satoru; Saito, Kazuki



Flavonoids: biosynthesis, biological functions, and biotechnological applications.  


Flavonoids are widely distributed secondary metabolites with different metabolic functions in plants. The elucidation of the biosynthetic pathways, as well as their regulation by MYB, basic helix-loop-helix (bHLH), and WD40-type transcription factors, has allowed metabolic engineering of plants through the manipulation of the different final products with valuable applications. The present review describes the regulation of flavonoid biosynthesis, as well as the biological functions of flavonoids in plants, such as in defense against UV-B radiation and pathogen infection, nodulation, and pollen fertility. In addition, we discuss different strategies and achievements through the genetic engineering of flavonoid biosynthesis with implication in the industry and the combinatorial biosynthesis in microorganisms by the reconstruction of the pathway to obtain high amounts of specific compounds. PMID:23060891

Falcone Ferreyra, María L; Rius, Sebastián P; Casati, Paula



Studies on identifying the binding sites of folate and its derivatives in Lactobacillus casei thymidylate synthase  

SciTech Connect

It was shown that folate and its derivatives have a profound effect on stabilizing thymidylate synthase in vitro and in vivo, as a consequence of ternary formation between the folate, dUMP, or FdUMP, and the synthase. The degree to which complex formation is affected can be revealed qualitatively by circular dichroism and quantitatively by equilibrium dialysis using the Lactobacillus casei synthase. In contrast to the pteroylmonoglutamates, the pteroylpolyglutamates bind to thymidylate synthase in the absence of dUMP, but even their binding affinity is increased greatly by this nucleotide or its analogues. Similarly, treatment of the synthase with carboxypeptidase A prevents the binding of the pteroylmonoglutamates and reduces the binding of the polyglutamates without affecting dUMP binding. The latter does not protect against carboxypeptidase inactivation but does potentiate the protective effect of the pteroylpolyglutamates. To determine the region of the synthase involved in the binding of the glutamate residues, Pte(/sup 14/C)GluGlu6 was activated by a water soluble carbodiimide in the presence and absence of dUMP. This folate derivative behaved as a competitive inhibitor of 5,10-CH/sub 2/H/sub 4/PteGlu, in contrast to methotrexate which was non-competitive. Separation of the five cyanogen bromide peptides from the L. casei synthase revealed 80% of the radioactivity to be associated with CNBr-2 and about 15% with CNBr-4. Chymotrypsin treatment of CNBr-2 yielded two /sup 14/C-labeled peaks on high performance liquid chromatography, with the slower migrating one being separated further into two peaks by Bio-gel P2 chromatography. All three peptides came from the same region of CNBr-2, encompassing residues 47-61 of the enzyme. From these studies it would appear that the residues most probably involved in the fixation of PteGlu7 are lysines 50 and 58. In contrast, methotrexate appeared to bind to another region of CNBr-2.

Maley, F.; Maley, G.F.



Reduced folate carrier-1 G80a gene polymorphism is associated with neuroblastoma's development.  


Neuroblastoma is a malignant embryonal tumor of neural crest cells that give rise to the sympathetic nervous system, responsible for 10-70% of all cases of childhood cancer. Because of its early appearance, it has been suggested that risk factors active in the prenatal can be associated with the pathogenesis of neuroblastoma. The aim of this study was to investigate whether the genetic polymorphisms MTHFR C677T and A1298C, MTR A2756G, TYMS 2R/3R and SLC19A1 G80A, involved in folate metabolism, increase the risk of neuroblastoma in Brazilian children. This study comprised 31 Brazilian children (0-14 years old) diagnosed with neuroblastoma compared with 92 controls. Investigation of polymorphisms MTHFR C677T, MTR A2756G and SLC19A1 A80G was performed using PCR-RFLP, the TYMS 2R/3R using PCR and MTHFR A1298C using AS-PCR. The SLC19A1 A80A genotype was significantly associated with the development of neuroblastoma, compared with the control group (Williams G-Test = 0.0286; OR = 5.1667; 95% CI = 1.4481-18.4338; p = 0.0175). When analyzed together, the 80AG+AA genotypes showed a trend toward association (OR = 3.3033; 95% CI = 1.0586-10.3080; p = 0.0563). Our results suggest that individuals carriers of genotype AA for the SLC19A1 gene present risk for the development of neuroblastoma and possibly have difficulty in absorption of folic acid by the cells, and this may adversely affect the metabolism of folate causing genomic instability and promoting the development of cancer. This is the first retrospective/prospective study to examine the relationship between polymorphisms of folate pathway genes and risk of neuroblastoma. PMID:24771227

de Miranda, Dyego O; Barros, Jemima E X S; Vieira, Maria Madalena S; Lima, Elker L S; Moraes, Vera L L; da Silva, Helker A; Garcia, Helder L B O; Lima, Cássia A; Gomes, Adriana V; Santos, Neide; Muniz, Maria T C



Association between dietary intake of folate and MTHFR and MTR genotype with risk of breast cancer.  


We investigated the association between dietary intake of folate, vitamin B6, and the 5,10-methylenetetrahydrofolate reductase (MTHFR) genotype with breast cancer. A matched case-control study was conducted, and 413 patients with newly diagnosed and histologically confirmed breast cancer and 436 controls were recruited. Folate intake, vitamin B6, and vitamin B12 levels were calculated, and the MTHFR C677T and A1298C and MTR A2756G polymorphisms were analyzed by polymerase chain reaction-restriction fragment length polymorphism. Breast cancer cases were generally older, older at first live birth, and younger at menarche, had a higher body mass index, were smokers, had higher energy intake, and more first-degree relatives with breast cancer as well as more live births compared to controls. With respect to energy intake, we found that higher energy intake were more likely to increase the risk of breast cancer. The MTHFR 667TT genotype was associated with a moderately increased risk of breast cancer when compared with the CC genotype, and a significant odds ratio (OR; 95% confidence interval, CI) was found (OR = 1.70, 95%CI = 1.06-2.73). Individuals carrying T allele were associated with higher risk of breast cancer when compared with C allele (OR = 1.34, 95%CI = 1.06-1.70). We did not find a significant effect of the MTHFR A1298C and MTR A2756G on the risk of breast cancer. We did not find any association between folate intake and MTHFR C677T polymorphisms. In conclusion, we found that the MTHFR C667T polymorphism is associated with the risk of breast cancer, indicating that this genotype plays a role in breast cancer development. PMID:25366783

He, J M; Pu, Y D; Wu, Y J; Qin, R; Zhang, Q J; Sun, Y S; Zheng, W W; Chen, L P



MR Imaging of Ovarian Tumors Using Folate-Receptor Targeted Contrast Agents  

PubMed Central

BACKGROUND: Because of its over-expression in many human tumors, the folate-receptor (FR) is a promising target for tumor-specific imaging. OBJECTIVE: To evaluate the uptake of FR-targeted gadolinium (P866) and iron-oxide (P1048) agents in an ovarian tumor model. MATERIALS AND METHODS: FR-positive ovarian cancer cells (IGROV-1) were incubated with FR-targeted agents (P866 or P1048) in the absence or presence of competing free folate. Intracellular gadolinium or iron-oxide concentrations were measured. MR imaging of implanted ovarian tumors in rats was performed following injection of FR-targeted (P866 and P1048) and non-targeted (P1001 and P904) agents. Changes in longitudinal and transverse relaxation rates (?R1 and ?R2), which were proportional to the contrast concentration in the tumors, were compared between tumors injected with FR-targeted and non-targeted agents. RESULTS: IGROV-1 cells showed uptake of P866 and P1048, which decreased with competing free folate. The ?R1 values were higher at 1h following P866 versus P1001 injection (p<0.05), indicating higher amount of contrast retained in the tumor following P866 injection. There was a trend of higher ?R2 values at 48h following P1048 versus P904 injection, although not statistically significant (p=0.09). CONCLUSION: A specific accumulation of the FR-targeted gadolinium agent P866 was suggested in a FR-positive ovarian tumor model. PMID:18357444

Wang, Zhen J.; Boddington, Sophie; Wendland, Michael; Meier, Reinhard; Corot, Claire; Daldrup-Link, Heike



Folate and Vitamin B12 Related Genes and Risk for Omphalocele  

PubMed Central

Both taking folic acid-containing vitamins around conception and consuming food fortified with folic acid have been reported to reduce omphalocele rates. Genetic factors are etiologically important in omphalocele as well; our pilot study showed a relationship with the folate metabolic enzyme gene methylenetetrahydrofolate reductase (MTHFR). We studied 169 non-aneuploid omphalocele cases and 761 unaffected, matched controls from all New York State births occurring between 1998 and 2005 to look for associations with single nucleotide polymorphisms (SNPs) known to be important in folate, vitamin B12, or choline metabolism. In the total study population, variants in the transcobalamin receptor gene (TCblR), rs2232775 (Q8R), and the MTHFR gene, rs1801131 (1298A>C), were significantly associated with omphalocele. In African-Americans significant associations were found with SNPs in genes for the vitamin B12 transporter (TCN2) and the vitamin B12 receptor (TCblR). A SNP in the homocysteine-related gene, betaine-homocysteine S-methyltransferase (BHMT), rs3733890 (R239Q), was significantly associated with omphalocele in both African-Americans and Asians. Only the TCblR association in the total population remained statistically significant if Bonferroni correction was applied. The finding that transcobalamin receptor (TCblR) and transporter (TCN2) SNPs and a BHMT SNP were associated with omphalocele suggests that disruption of methylation reactions, in which folate, vitamin B12, and homocysteine play critical parts, may be a risk factor for omphalocele. Our data, if confirmed, suggest that supplements containing both folic acid and vitamin B12 may be beneficial in preventing omphaloceles. PMID:22116453

Mills, James L.; Carter, Tonia C.; Kay, Denise M.; Browne, Marilyn; Brody, Lawrence C.; Liu, Aiyi; Romitti, Paul A.; Caggana, Michele; Druschel, Charlotte



A folate receptor-targeting nanoparticle minimizes drug resistance in a human cancer model.  


Resistance to chemotherapy is a major obstacle in cancer therapy. The main purpose of this study is to evaluate the potential of a folate receptor-targeting nanoparticle to overcome/minimize drug resistance and to explore the underlying mechanisms. This is accomplished with enhanced cellular accumulation and retention of paclitaxel (one of the most effective anticancer drugs in use today and a well-known P-glycoprotein (P-gp) substrate) in a P-gp-overexpressing cancer model. The folate receptor-targeted nanoparticle, HFT-T, consists of a heparin-folate-paclitaxel (HFT) backbone with an additional paclitaxel (T) loaded in its hydrophobic core. In vitro analyses demonstrated that the HFT-T nanoparticle was superior to free paclitaxel or nontargeted nanoparticle (HT-T) in inhibiting proliferation of P-gp-overexpressing cancer cells (KB-8-5), partially due to its enhanced uptake and prolonged intracellular retention. In a subcutaneous KB-8-5 xenograft model, HFT-T administration enhanced the specific delivery of paclitaxel into tumor tissues and remarkably prolonged retention within tumor tissues. Importantly, HFT-T treatment markedly retarded tumor growth in a xenograft model of resistant human squamous cancer. Immunohistochemical analysis further indicated that increased in vivo efficacy of HFT-T nanoparticles was associated with a higher degree of microtubule stabilization, mitotic arrest, antiangiogenic activity, and inhibition of cell proliferation. These findings suggest that when the paclitaxel was delivered as an HFT-T nanoparticle, the drug is better retained within the P-gp-overexpressing cells than the free form of paclitaxel. These results indicated that the targeted HFT-T nanoparticle may be promising in minimizing P-gp related drug resistance and enhancing therapeutic efficacy compared with the free form of paclitaxel. PMID:21728341

Wang, Xu; Li, Jun; Wang, Yuxiang; Koenig, Lydia; Gjyrezi, Ada; Giannakakou, Paraskevi; Shin, Edwin H; Tighiouart, Mourad; Chen, Zhuo Georgia; Nie, Shuming; Shin, Dong M



A target-triggered exponential amplification-based DNAzyme biosensor for ultrasensitive detection of folate receptors.  


We develop a new method for ultrasensitive detection of folate receptors (FRs) using a target-triggered isothermally exponential amplification reaction (EXPAR)-based DNAzyme biosensor. This method exhibits excellent specificity and high sensitivity with a detection limit as low as 0.23 fM and a large dynamic range of 6 orders of magnitude from 1 fM to 1 nM. It might be further applied for the detection of various small molecule-binding proteins by simply changing the linked small molecule moiety of the hairpin probes. PMID:25350483

Wang, Li-Juan; Zhang, Yan; Zhang, Chun-Yang



Hearing impairment risk and interaction of folate metabolism related gene polymorphisms in an aging study  

PubMed Central

Background Recent investigations demonstrated many genetic contributions to the development of human age-related hearing impairment (ARHI), however, reports of factors associated with a reduction in the ARHI risk are rare. Folate metabolism is essential for cellular functioning. Despite the extensive investigations regarding the roles of folate metabolism related gene polymorphisms in the pathophysiology of complex diseases, such as cancer, cardio-cerebrovascular disease, and atherosclerosis, little is known about the association with ARHI. The aim of this study is to investigate the effects of the methionine synthase (MTR) A2756G and methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphisms on the risk of hearing impairment in middle-aged and elderly Japanese. Methods Data were collected from community-dwelling Japanese adults aged 40-84 years who participated in the Longitudinal Study of Aging biennially between 1997 and 2008. We analyzed cumulative data (5,167 samples in accumulated total) using generalized estimating equations. Results The MTHFR 677T allele was significantly associated with a reduced risk of hearing impairment only when the subjects were wild-type homozygotes for MTR A2756G. The per-T allele odds ratio of MTHFR for the risk of developing hearing impairment was 0.7609 (95% CI: 0.6178-0.9372) in the MTR AA genotype. In addition, a subgroup analysis demonstrated that the favorable effect of the MTHFR 677T allele on the risk of developing hearing impairment was independent of folate and homocysteine level, whereas plasma total homocysteine level was independently associated with an increased risk of developing hearing impairment. The interactive effect of gene polymorphisms associated with folate metabolism may modify the risk of developing hearing impairment after middle age. These results contribute to the elucidation of the causes of ARHI. Conclusions The present study has found that the MTHFR 677T allele has a favorable effect on a risk of hearing impairment in the middle-aged and elderly population, only when the individuals were wild-type homozygotes for MTR A2756G. PMID:21385350



Combinatorial biosynthesis for new drug discovery  

Microsoft Academic Search

Combinatorial biosynthesis involves interchanging secondary metabolism genes between antibiotic-producing microorganisms to create unnatural gene combinations or hybrid genes if only part of a gene is exchanged. Novel metabolites can be made by both approaches, due to the effect of a new enzyme on a metabolic pathway or to the formation of proteins with new enzymatic properties. The method has been

C Richard Hutchinson



Cofactor regeneration for sustainable enzymatic biosynthesis  

Microsoft Academic Search

Oxidoreductases are attractive catalysts for biosynthesis of chiral compounds and polymers, construction of biosensors, and degradation of environmental pollutants. Their practical applications, however, can be quite challenging since they often require cofactors such as nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP). These cofactors are generally expensive. Efficient regeneration of cofactors is therefore critical to the economic viability

Wenfang Liu; Ping Wang



Studies of chlorophyll biosynthesis in Russia.  


History of the studies of chlorophyll biosynthesis by Russian and Byelorussian scientists starting from those by Kliment Timiriazeff (also spelled as Timiriazev) and Nikolay ( also spelled as Nikolai) Monteverde (late 19th century) to the present time are summarized here. PMID:16228596

Belyaeva, Olga B



Outlining eicosanoid biosynthesis in the crustacean Daphnia  

PubMed Central

Background Eicosanoids are biologically active, oxygenated metabolites of three C20 polyunsaturated fatty acids. They act as signalling molecules within the autocrine or paracrine system in both vertebrates and invertebrates mainly functioning as important mediators in reproduction, the immune system and ion transport. The biosynthesis of eicosanoids has been intensively studied in mammals and it is known that they are synthesised from the fatty acid, arachidonic acid, through either the cyclooxygenase (COX) pathway; the lipoxygenase (LOX) pathway; or the cytochrome P450 epoxygenase pathway. However, little is still known about the synthesis and structure of the pathway in invertebrates. Results Here, we show transcriptomic evidence from Daphnia magna (Crustacea: Branchiopoda) together with a bioinformatic analysis of the D. pulex genome providing insight on the role of eicosanoids in these crustaceans as well as outlining a putative pathway of eicosanoid biosynthesis. Daphnia appear only to have one copy of the gene encoding the key enzyme COX, and phylogenetic analysis reveals that the predicted protein sequence of Daphnia COX clusters with other invertebrates. There is no current evidence of an epoxygenase pathway in Daphnia; however, LOX products are most certainly synthesised in daphnids. Conclusion We have outlined the structure of eicosanoid biosynthesis in Daphnia, a key genus in freshwater ecosystems. Improved knowledge of the function and synthesis of eicosanoids in Daphnia and other invertebrates could have important implications for several areas within ecology. This provisional overview of daphnid eicosanoid biosynthesis provides a guide on where to focus future research activities in this area. PMID:18625039

Heckmann, Lars-Henrik; Sibly, Richard M; Timmermans, Martijn JTN; Callaghan, Amanda



Outlining eicosanoid biosynthesis in the crustacean Daphnia  

Microsoft Academic Search

BACKGROUND: Eicosanoids are biologically active, oxygenated metabolites of three C20 polyunsaturated fatty acids. They act as signalling molecules within the autocrine or paracrine system in both vertebrates and invertebrates mainly functioning as important mediators in reproduction, the immune system and ion transport. The biosynthesis of eicosanoids has been intensively studied in mammals and it is known that they are synthesised

Lars-Henrik Heckmann; Richard M Sibly; Martijn JTN Timmermans; Amanda Callaghan



Unusual sugar biosynthesis and natural product glycodiversification  

Microsoft Academic Search

The enzymes involved in the biosynthesis of carbohydrates and the attachment of sugar units to biological acceptor molecules catalyse an array of chemical transformations and coupling reactions. In prokaryotes, both common sugar precursors and their enzymatically modified derivatives often become substituents of biologically active natural products through the action of glycosyltransferases. Recently, researchers have begun to harness the power of

Christopher J. Thibodeaux; Charles E. Melançon; Hung-wen Liu



Evolutionarily Conserved Optimization of Amino Acid Biosynthesis  

E-print Network

Springer Science+Business Media, LLC 2007 Abstract The ``cognate bias hypothesis'' states that early previously demonstrated reduced cognate bias in amino acid biosyn- thetic pathways. Here we show that cognate bias in amino acid biosynthesis is present in the other domains of life--Archaebacteria and Eukaryota

de Bivort, Benjamin


Cell Metabolism Regulation of Ceramide Biosynthesis  

E-print Network

Cell Metabolism Article Regulation of Ceramide Biosynthesis by TOR Complex 2 Sofia Aronova,1 Karen.11.015 SUMMARY Ceramides and sphingoid long-chain bases (LCBs) are precursors to more complex sphingolipids. cerevisiae; however, the precise step regulated by this complex remains unknown. Here we demon- strate

Hammock, Bruce D.


p73 regulates serine biosynthesis in cancer.  


Activation of serine biosynthesis supports growth and proliferation of cancer cells. Human cancers often exhibit overexpression of phosphoglycerate dehydrogenase (PHGDH), the metabolic enzyme that catalyses the reaction that diverts serine biosynthesis from the glycolytic pathway. By refueling serine biosynthetic pathways, cancer cells sustain their metabolic requirements, promoting macromolecule synthesis, anaplerotic flux and ATP. Serine biosynthesis intersects glutaminolysis and together with this pathway provides substrates for production of antioxidant GSH. In human lung adenocarcinomas we identified a correlation between serine biosynthetic pathway and p73 expression. Metabolic profiling of human cancer cell line revealed that TAp73 activates serine biosynthesis, resulting in increased intracellular levels of serine and glycine, associated to accumulation of glutamate, tricarboxylic acid (TCA) anaplerotic intermediates and GSH. However, at molecular level p73 does not directly regulate serine metabolic enzymes, but transcriptionally controls a key enzyme of glutaminolysis, glutaminase-2 (GLS-2). p73, through GLS-2, favors conversion of glutamine in glutamate, which in turn drives the serine biosynthetic pathway. Serine and glutamate can be then employed for GSH synthesis, thus the p73-dependent metabolic switch enables potential response against oxidative stress. In knockdown experiment, indeed, TAp73 depletion completely abrogates cancer cell proliferation capacity in serine/glycine-deprivation, supporting the role of p73 to help cancer cells under metabolic stress. These findings implicate p73 in regulation of cancer metabolism and suggest that TAp73 influences glutamine and serine metabolism, affecting GSH synthesis and determining cancer pathogenesis. PMID:24186203

Amelio, I; Markert, E K; Rufini, A; Antonov, A V; Sayan, B S; Tucci, P; Agostini, M; Mineo, T C; Levine, A J; Melino, G



Folate-targeted liposome encapsulating chitosan/oligonucleotide polyplexes for tumor targeting.  


We previously reported that a liposome encapsulating polyethylenimine/oligonucleotides is suitable for in vivo delivery of nucleic acid therapeutics. However, toxicity of polyethylenimine is an obstacle in clinical application. To develop a liposome encapsulating polyplexes applicable to clinical use, we proposed to replace polyethylenimine with chitosan and thus constructed the liposome encapsulating low-molecular weight chitosan (LMWC)/oligonucleotide (ODN) polyplexes [LS(CO)]. ODN was completely complexed to LMWC at pH 5.5 and an N/P ratio 10 with a positive zeta potential of 19.81?±?1.11. The positively charged polyplexes were encapsulated into anionic liposome by membrane extrusion. Folate-targeted liposome encapsulating LMWC/ODN complex [FLS(CO)] was prepared by adding folate-conjugated phospholipid. The resulting LS(CO) and FLS(CO) were characterized with respect to size distribution, zeta potential, and colloidal stability. The LS(CO) and FLS(CO) were also evaluated for in vitro cellular uptake and cytotoxicity. The LS(CO) and FLS(CO) showed a narrow size distribution with a mean diameter of about 130 nm and neutral zeta potentials and remained stable for 7 days in 0.15-M NaCl at room temperature. FLS(CO) showed higher cellular uptake than LS(CO) in B16F10 murine melanoma cells. Furthermore, LS(CO) showed less toxicity as compared to liposome encapsulating polyethylenimine/oligonucleotides, representing a biocompatible nanocarrier of oligonucleotide therapeutics. PMID:24848761

Kang, Ji Hee; Battogtokh, Gantumur; Ko, Young Tag



Hormonal alteration of methotrexate and folate polyglutamate formation in cultured hepatoma cells.  


Glutamylation of the antifolate methotrexate in H35 hepatoma cells was stimulated by physiologic concentrations of insulin and dexamethasone. At saturating concentrations of the hormone a 2.7-fold stimulation could be obtained with insulin (65 nM, 16-h exposure) and a 1.8-fold stimulation with dexamethasone (100 nM, 16-h exposure). The increases in glutamylation caused by the hormones were not additive, and both were inhibited by actinomycin D and cycloheximide. N6,O2'-dibutyryl cAMP and theophylline caused a modest reduction of glutamylation in control and dexamethasone-treated cultures, but repressed the stimulation caused by insulin by approximately one-third. Enhancement of synthesis by dexamethasone and insulin was associated with increases in the tri-, tetra-, and pentaglutamate derivatives of methotrexate, with little change in intracellular methotrexate and methotrexate diglutamate. When the conversion of folinic acid into the folylpolyglutamate pool was examined in folate-depleted H35 cells, insulin and dexamethasone had similar effects. The results suggest that these hormones play a role in the glutamylation of the folate coenzymes in a liver-derived transformed cell line in culture and that these effects are also reflected in the interaction of the cells with antifolates such as methotrexate. PMID:6370141

Galivan, J



In vivo photoacoustic molecular imaging of breast carcinoma with folate receptor-targeted indocyanine green nanoprobes.  


As an optical-acoustic hybrid imaging technology, photoacoustic imaging uniquely combines the advantages of rich optical contrast with high ultrasonic resolution in depth, opening up many new possibilities not attainable with conventional pure optical imaging technologies. To perform photoacoustic molecular imaging, optically absorbing exogenous contrast agents are needed to enhance the signals from specifically targeted disease activity. In this work, we designed and developed folate receptor targeted, indocyanine green dye doped poly(d,l-lactide-co-glycolide) lipid nanoparticles (FA-ICG-PLGA-lipid NPs) for molecular photoacoustic imaging of tumor. The fabricated FA-ICG-PLGA-lipid NPs exhibited good aqueous stability, a high folate-receptor targeting efficiency, and remarkable optical absorption in near-infrared wavelengths, providing excellent photoacoustic signals in vitro. Furthermore, after intravenous administration of FA-ICG-PLGA-lipid NPs, mice bearing MCF-7 breast carcinomas showed significantly enhanced photoacoustic signals in vivo in the tumor regions, compared with those using non-targeted ICG-PLGA-lipid NPs. Given the existing wide clinical use of ICG and PLGA, the developed FA-ICG-PLGA-lipid NPs, in conjunction with photoacoustic imaging technology, offer a great potential to be translated into the clinic for non-ionizing molecular imaging of breast cancer in vivo. PMID:25321626

Wang, Huina; Liu, Chengbo; Gong, Xiaojing; Hu, Dehong; Lin, Riqiang; Sheng, Zonghai; Zheng, Cuifang; Yan, Meng; Chen, Jingqin; Cai, Lintao; Song, Liang



Genetic variant in folate homeostasis is associated with lower warfarin dose in African Americans  

PubMed Central

The anticoagulant warfarin has >30 million prescriptions per year in the United States. Doses can vary 20-fold between patients, and incorrect dosing can result in serious adverse events. Variation in warfarin pharmacokinetic and pharmacodynamic genes, such as CYP2C9 and VKORC1, do not fully explain the dose variability in African Americans. To identify additional genetic contributors to warfarin dose, we exome sequenced 103 African Americans on stable doses of warfarin at extremes (?35 and ?49 mg/week). We found an association between lower warfarin dose and a population-specific regulatory variant, rs7856096 (P = 1.82 × 10?8, minor allele frequency = 20.4%), in the folate homeostasis gene folylpolyglutamate synthase (FPGS). We replicated this association in an independent cohort of 372 African American subjects whose stable warfarin doses represented the full dosing spectrum (P = .046). In a combined cohort, adding rs7856096 to the International Warfarin Pharmacogenetic Consortium pharmacogenetic dosing algorithm resulted in a 5.8 mg/week (P = 3.93 × 10?5) decrease in warfarin dose for each allele carried. The variant overlaps functional elements and was associated (P = .01) with FPGS gene expression in lymphoblastoid cell lines derived from combined HapMap African populations (N = 326). Our results provide the first evidence linking genetic variation in folate homeostasis to warfarin response. PMID:25079360

Daneshjou, Roxana; Gamazon, Eric R.; Burkley, Ben; Cavallari, Larisa H.; Johnson, Julie A.; Klein, Teri E.; Limdi, Nita; Hillenmeyer, Sara; Percha, Bethany; Karczewski, Konrad J.; Langaee, Taimour; Patel, Shitalben R.; Bustamante, Carlos D.; Altman, Russ B.



Genetic variant in folate homeostasis is associated with lower warfarin dose in African Americans.  


The anticoagulant warfarin has >30 million prescriptions per year in the United States. Doses can vary 20-fold between patients, and incorrect dosing can result in serious adverse events. Variation in warfarin pharmacokinetic and pharmacodynamic genes, such as CYP2C9 and VKORC1, do not fully explain the dose variability in African Americans. To identify additional genetic contributors to warfarin dose, we exome sequenced 103 African Americans on stable doses of warfarin at extremes (?35 and ?49 mg/week). We found an association between lower warfarin dose and a population-specific regulatory variant, rs7856096 (P = 1.82 × 10(-8), minor allele frequency = 20.4%), in the folate homeostasis gene folylpolyglutamate synthase (FPGS). We replicated this association in an independent cohort of 372 African American subjects whose stable warfarin doses represented the full dosing spectrum (P = .046). In a combined cohort, adding rs7856096 to the International Warfarin Pharmacogenetic Consortium pharmacogenetic dosing algorithm resulted in a 5.8 mg/week (P = 3.93 × 10(-5)) decrease in warfarin dose for each allele carried. The variant overlaps functional elements and was associated (P = .01) with FPGS gene expression in lymphoblastoid cell lines derived from combined HapMap African populations (N = 326). Our results provide the first evidence linking genetic variation in folate homeostasis to warfarin response. PMID:25079360

Daneshjou, Roxana; Gamazon, Eric R; Burkley, Ben; Cavallari, Larisa H; Johnson, Julie A; Klein, Teri E; Limdi, Nita; Hillenmeyer, Sara; Percha, Bethany; Karczewski, Konrad J; Langaee, Taimour; Patel, Shitalben R; Bustamante, Carlos D; Altman, Russ B; Perera, Minoli A



COMMUNICATION: Folate and S-adenosylmethionine modulate synaptic activity in cultured cortical neurons: acute differential impact on normal and apolipoprotein-deficient mice  

NASA Astrophysics Data System (ADS)

Folate deficiency is accompanied by a decline in the cognitive neurotransmitter acetylcholine and a decline in cognitive performance in mice lacking apolipoprotein E (ApoE-/- mice), a low-density lipoprotein that regulates aspects of lipid metabolism. One direct consequence of folate deficiency is a decline in S-adenosylmethionine (SAM). Since dietary SAM supplementation maintains acetylcholine levels and cognitive performance in the absence of folate, we examined herein the impact of folate and SAM on neuronal synaptic activity. Embryonic cortical neurons from mice expressing or lacking ApoE (ApoE+/+ or -/-, respectively) were cultured for 1 month on multi-electrode arrays, and signaling was recorded. ApoE+/+ cultures displayed significantly more frequent spontaneous signals than ApoE-/- cultures. Supplementation with 166 µm SAM (not normally present in culture medium) increased signal frequency and decreased signal amplitude in ApoE+/+ cultures. SAM also increased the frequency of tightly clustered signal bursts. Folate deprivation reversibly reduced signal frequency in ApoE+/+ cultures; SAM supplementation maintained signal frequency despite folate deprivation. These findings support the importance of dietary supplementation with folate and SAM on neuronal health. Supplementation with 166 µm SAM did not alter signaling in ApoE-/- cultures, which may be a reflection of the reduced SAM levels in ApoE-/- mice. The differential impact of SAM on ApoE+/+ and -/- neurons underscores the combined impact of nutritional and genetic deficiencies on neuronal homeostasis.

Serra, Michael; Chan, Amy; Dubey, Maya; Gilman, Vladimir; Shea, Thomas B.



Molecular mechanisms underlying the anti-proliferative and anti-migratory effects of folate on homocysteinechallenged rat aortic smooth muscle cells  

PubMed Central

Background and Purpose Homocysteine is an intermediate product formed during the metabolism of methionine, and is increased in cells with folate deficiency. Patients with hyperhomocysteinemia tend to develop cardiovascular disease. Here, we have examined the molecular mechanisms underlying the anti-proliferative and anti-migratory effects of folate on homocysteine-challenged rat aortic smooth muscle cells (RASMCs). Experimental Approach Cultures of RASMC were challenged with homocysteine and then incubated with folate added. Changes in p21/p27, AKT and RhoA were followed by RT-PCR, Western blotting and immunocytochemistry. Transfection and anti-sense techniques were also used. Cell viability, growth and migration were measured. Key Results Folate up-regulated p21/p27 through a Src/ERK-dependent mechanism that accounted for its anti-proliferative effects on RASMC. Folate protected RASMC from the effects of homocysteine by reducing AKT1, focal adhesion kinase (FAK), paxillin, and p190RhoGAP activation/phosphorylation, along with cytosolic levels of p21 and p27, and increasing RhoA activation. Overexpression of AKT1, but not of AKT2, induced p21/p27 phosphorylation and increased cytosolic p21/p27 levels, as did homocysteine treatment. By contrast, and similarly to folate treatment, transfection with dominant negative (DN) AKT1 counteracted these effects. Additionally, AKT was shown to be an upstream target of FAK activation. In RASMC overexpressing constitutively active RhoA, activation of RhoA mediated the anti-migratory effects of folate. Addition of Y27632 (a RhoA inhibitor) and DNRhoA counteracted the anti-migratory effects, confirming RhoA involvement. Conclusion and implications Folate was anti-proliferative and anti-migratory in homocysteine-challenged RASMC. Mechanisms underlying folate-mediated protection against the proatherosclerotic effects of homocysteine have been delineated. PMID:23424995

Chou, Ying; Lin, Hui-Chen; Chen, Kuan-Chou; Chang, Chi-Cheng; Lee, Wen-Sen; Juan, Shu-Hui



Synthesis and Characterization of Folate-Targeted Dextran/Retinoic Acid Micelles for Doxorubicin Delivery in Acute Leukemia  

PubMed Central

Folate and retinoic acid grafted/dextran (FA-RA/DEX) copolymers with different molecular weight of DEX were synthesized using carbonyldiimidazole and dimethylaminopyridine for targeted delivery of doxorubicin (DOX) in acute myelogenous leukemia (AML). The copolymers structure was confirmed by 1H NMR and FTIR. Critical micelle concentration (CMC) of each copolymer was determined using pyrene as a fluorescent probe. DOX was loaded in micelles by the direct dissolution method. Physical properties of micelles, including particle size, zeta potential, drug loading efficiency, and drug release profiles, were examined. The orientation of the folate ligand on the surface of the micelles was studied by X-ray photoelectron spectroscopy (XPS) technique. The cytotoxicity of micelles loaded with DOX at different concentrations was studied in KG1 cells using MTT assay and their cellular uptake by flow cytometry technique. FTIR and 1H NMR spectra confirmed successful production of the targeted micelles and XPS spectra showed the surface orientation of folate. R15D10F7 copolymer produced micelles with particle size of 82.86?nm, polydispersity index of 0.3, zeta potential of ?4.68?mV, drug loading efficiency of 96%, and release efficiency of 63%. DOX loaded in folate-targeted micelles of RA/DEX was more toxic than that in nontargeted micelles and free drug and seems promising in reducing drug resistance in AML. PMID:24719872

Varshosaz, J.; Hassanzadeh, F.; Sadeghi Aliabadi, H.; Nayebsadrian, M.; Banitalebi, M.; Rostami, M.



Synthesis and characterization of folate-targeted dextran/retinoic acid micelles for doxorubicin delivery in acute leukemia.  


Folate and retinoic acid grafted/dextran (FA-RA/DEX) copolymers with different molecular weight of DEX were synthesized using carbonyldiimidazole and dimethylaminopyridine for targeted delivery of doxorubicin (DOX) in acute myelogenous leukemia (AML). The copolymers structure was confirmed by (1)H NMR and FTIR. Critical micelle concentration (CMC) of each copolymer was determined using pyrene as a fluorescent probe. DOX was loaded in micelles by the direct dissolution method. Physical properties of micelles, including particle size, zeta potential, drug loading efficiency, and drug release profiles, were examined. The orientation of the folate ligand on the surface of the micelles was studied by X-ray photoelectron spectroscopy (XPS) technique. The cytotoxicity of micelles loaded with DOX at different concentrations was studied in KG1 cells using MTT assay and their cellular uptake by flow cytometry technique. FTIR and (1)H NMR spectra confirmed successful production of the targeted micelles and XPS spectra showed the surface orientation of folate. R15D10F7 copolymer produced micelles with particle size of 82.86 nm, polydispersity index of 0.3, zeta potential of -4.68 mV, drug loading efficiency of 96%, and release efficiency of 63%. DOX loaded in folate-targeted micelles of RA/DEX was more toxic than that in nontargeted micelles and free drug and seems promising in reducing drug resistance in AML. PMID:24719872

Varshosaz, J; Hassanzadeh, F; Sadeghi Aliabadi, H; Nayebsadrian, M; Banitalebi, M; Rostami, M



Antisense Oligonucleotides Targeting Folate Receptor Alpha, and the Use Thereof (PAT-APPL-11-328 449).  

National Technical Information Service (NTIS)

The invention relates to treatment of cancers and cancerous cells which over-express alpha folate receptor (FR(alpha)) compared to the normal cells of the same tissue. The invention is directed to antisense oligonucleotides which are complimentary to the ...

K. N. Chung, M. S. Jhaveri, P. C. Elwood



Fear of fatness among young Irish adolescents : association with obesity, reported iron and folate intake, and dental health  

Microsoft Academic Search

OBJECTIVE: To establish the prevalence of fear of fatness (the desire to be thinner) and associated factors, including obesity, reported energy, iron and folate intakes. The difficulties in defining overweight among Irish children and an assessment of dietary and socio-economic factors related to dental caries and also reported in the group. METHODS: A one-year follow up study of 251 healthy

Anne C. Griffin



Brief Report: Are Autistic-Behaviors in Children Related to Prenatal Vitamin Use and Maternal Whole Blood Folate Concentrations?  

ERIC Educational Resources Information Center

Prenatal multivitamin/folic acid supplement use may reduce the risk of autism spectrum disorders. We investigated whether 2nd trimester prenatal vitamin use and maternal whole blood folate (WBF) concentrations were associated with Social Responsiveness Scale (SRS) scores at 4-5 years of age in a prospective cohort of 209 mother-child pairs. After…

Braun, Joseph M.; Froehlich, Tanya; Kalkbrenner, Amy; Pfeiffer, Christine M.; Fazili, Zia; Yolton, Kimberly; Lanphear, Bruce P.



Fabrication of folate bioconjugated near-infrared fluorescent silver nanoclusters for targeted in vitro and in vivo bioimaging.  


Thiolpolyethyleneimine stabilized silver nanoclusters (SH-PEI-AgNCs) with intense NIR fluorescence and chemical stability were fabricated in aqueous solution. The SH-PEI-AgNCs were subsequently bioconjugated with folate for targeted in vitro and in vivo bioimaging. PMID:25285944

Wang, Yong; Dai, Cong; Yan, Xiu-Ping



A pilot study on the contribution of folate gene variants in the cognitive function of ADHD probands.  


Genetic abnormalities in components important for the folate cycle confer risk for various disorders since adequate folate turnover is necessary for normal methylation, gene expression and chromosome structure. However, the system has rarely been studied in children diagnosed with attention deficit hyperactivity disorder (ADHD). We hypothesized that ADHD related cognitive deficit could be attributed to abnormalities in the folate cycle and explored functional single nucleotide polymorphisms in methylenetetrahydrofolate dehydrogenase (rs2236225), reduced folate carrier (rs1051266), and methylenetetrahydrofolate reductase (rs1801131 and rs1801133) in families with ADHD probands (N = 185) and ethnically matched controls (N = 216) recruited following the DSM-IV. After obtaining informed written consent for participation, peripheral blood was collected for genomic DNA isolation and PCR-based analysis of target sites. Data obtained was analyzed by UNPHASED. Interaction between sites was analyzed by the multi dimensionality reduction (MDR) program. Genotypic frequencies of the Indian population were strikingly different from other ethnic groups. rs1801133 "T" allele showed biased transmission in female probands (p < 0.05). Significant difference in genotypic frequencies for female probands was also noticed. rs1801131 and rs1801133 showed an association with low intelligence quotient (IQ). MDR analysis exhibited independent effects and contribution of these sites to IQ, thus indicating a role of these genes in ADHD related cognitive deficit. PMID:25079255

Saha, T; Dutta, S; Rajamma, U; Sinha, S; Mukhopadhyay, K



Folate-encoded and Fe3O4-loaded polymeric micelles for dual targeting of cancer cells  

E-print Network

Folate-encoded and Fe3O4-loaded polymeric micelles for dual targeting of cancer cells Xiaoqiang the potential of these polymeric micelles as an effective dual targeting nanoplatform for the delivery reserved. 1. Introduction Over the past decades, polymeric micelles have drawn consid- erable interests

Gao, Jinming


Characterization of the pH of Folate Receptor-Containing Endosomes and the Rate of Hydrolysis of Internalized  

E-print Network

potentially intro- duce steric hindrances and prevent association of the drug with its molecular target of Internalized Acid-Labile Folate-Drug ConjugatesS Jun Yang,1 Hongtao Chen, Iontcho R. Vlahov, Ji-Xin ChengH-dependent drug release from a ligand-targeted drug con- jugate during receptor-mediated endocytosis is lacking

Cheng, Ji-Xin


A folate-rich diet is as effective as folic acid from supplements in decreasing plasma homocysteine concentrations  

Microsoft Academic Search

st tr ra ac ct t Background & Aims: At least 500 µg of folic acid are required daily to treat hyperhomocysteinemia. To reach this amount by dietary changes alone may be difficult because food has a low folic acid content and bioavailability. No studies have compared the effects of similar amounts of additional folate derived from a combination of

M. Antonia Vilaseca; Susana Balcells; Rafael Artuch; Emili Corbella; José F. Meco; Ramon Vila; Ramon Pujol; Daniel Grinberg



Expression and activity of methionine cycle genes are altered following folate and vitamin E deficiency under oxidative challenge: Modulation  

E-print Network

oxidative damage and potentiates the deleterious effects of apolipoprotein E (ApoE) deficiency. Mice lacking ApoE (ApoE 2 /2 mice) upregulate the expression and activity of another enzyme, glutathione synthase. Herein, we examined the influence of ApoE and folate deficiency on expression and activity of several

Graves, Michael V.


Lower Maternal Folate Status in Early Pregnancy Is Associated with Childhood Hyperactivity and Peer Problems in Offspring  

ERIC Educational Resources Information Center

Background: Maternal nutrition during pregnancy has been linked with fetal brain development and psychopathology in the offspring. We examined for associations of maternal folate status and dietary intake during pregnancy with brain growth and childhood behavioural difficulties in the offspring. Methods: In a prospective cohort study, maternal red…

Schlotz, Wolff; Jones, Alexander; Phillips, David I. W.; Gale, Catharine R.; Robinson, Sian M.; Godfrey, Keith M.



The Status of Vitamin B12 and Folate among Chinese Women: A Population-Based Cross-Sectional Study in Northwest China  

PubMed Central

Objective To assess the status of the vitamin B12 and folate of Chinese women living in northwest China. Methods A population-based cross-sectional study was conducted in 2008 among Chinese women aged 10–49 years living in Shaanxi province of northwest China. A stratified multistage random sampling method was adopted to obtain a sample of 1170 women. The women were interviewed for collection of their background information and their plasma vitamin B12 and folate were measured with the immunoassay method. The status of both vitamins was evaluated and the prevalence of deficiency was estimated. Results The median value of the women was 214.5 pg/mL for vitamin B12 and 4.6 ng/mL for folate. The urban women had a significantly higher vitamin B12 (254.1 vs. 195.9 pg/mL) but lower folate (4.4 vs. 4.7 ng/mL) than rural women. Total prevalence of deficiency was 45.5% (95% CI: 42.6%?48.4%) for vitamin B12 and 14.7% (95% CI: 12.6%?16.8%) for folate. About 36% of women presented vitamin B12 deficiency alone, 5.2% belonged to folate deficiency alone and 9.5% was combined deficiency in both vitamins. More than 25% of the women were in marginal vitamin B12 status (200–299 pg/mL) and 60% in marginal status of folate (3–6 ng/mL). About 75.2% of rural women with folate deficiency were deficient in vitamin B12 and 46% for urban women. Quantile regression model found decreasing coefficient of folate status across 73 different quantiles of vitamin B12, which indicated that the women with folate deficiency had lower vitamin B12 significantly compared with those with no deficiency. Conclusions The deficiency of vitamin B12 and folate is still prevalent among the Chinese women in northwest China. Vitamin B12 deficiency could be more serious and the improvement of poor vitamin B12 status should be invoked when practicing the supplementation of folate against the neural tube defects in northwest China. PMID:25390898

Dang, Shaonong; Yan, Hong; Zeng, Lingxia; Wang, Quanli; Li, Qiang; Xiao, Shengbin; Fan, Xiaojing



Chemical genetics to examine cellulose biosynthesis  

PubMed Central

Long-term efforts to decode plant cellulose biosynthesis via molecular genetics and biochemical strategies are being enhanced by the ever-expanding scale of omics technologies. An alternative approach to consider are the prospects for inducing change in plant metabolism using exogenously supplied chemical ligands. Cellulose biosynthesis inhibitors (CBIs) have been identified among known herbicides, during diverse combinatorial chemical libraries screens, and natural chemical screens from microbial agents. In this review, we summarize the current knowledge of the inhibitory effects of CBIs and further group them by how they influence fluorescently tagged cellulose synthase A proteins. Additional attention is paid to the continuing development of the CBI toolbox to explore the cell biology and genetic mechanisms underpinning effector molecule activity. PMID:23372572

Brabham, Chad; DeBolt, Seth



Auxin Biosynthesis in Maize Kernels1  

PubMed Central

Auxin biosynthesis was analyzed in a maize (Zea mays) kernel culture system in which the seeds develop under physiological conditions similar to the in vivo situation. This system was modified for precursor feeding experiments. Tryptophan (Trp) is efficiently incorporated into indole-3-acetic acid (IAA) with retention of the 3,3? bond. Conversion of Trp to IAA is not competed by indole. Labeling with the general precursors [U-13C6]glucose and [1,2-13C2]acetate followed by retrobiosynthetic analysis strongly suggest that Trp-dependent IAA synthesis is the predominant route for auxin biosynthesis in the maize kernel. The synthesis of IAA from indole glycerol phosphate and IAA formation via condensation of indole with an acetyl-coenzyme A or phosphoenolpyruvate derived metabolite can be excluded. PMID:10889260

Glawischnig, Erich; Tomas, Adriana; Eisenreich, Wolfgang; Spiteller, Peter; Bacher, Adelbert; Gierl, Alfons



Biosynthesis of Polyketides in Heterologous Hosts  

PubMed Central

Polyketide natural products show great promise as medicinal agents. Typically the products of microbial secondary biosynthesis, polyketides are synthesized by an evolutionarily related but architecturally diverse family of multifunctional enzymes called polyketide synthases. A principal limitation for fundamental biochemical studies of these modular megasynthases, as well as for their applications in biotechnology, is the challenge associated with manipulating the natural microorganism that produces a polyketide of interest. To ameliorate this limitation, over the past decade several genetically amenable microbes have been developed as heterologous hosts for polyketide biosynthesis. Here we review the state of the art as well as the difficulties associated with heterologous polyketide production. In particular, we focus on two model hosts, Streptomyces coelicolor and Escherichia coli. Future directions for this relatively new but growing technological opportunity are also discussed. PMID:11238987

Pfeifer, Blaine A.; Khosla, Chaitan



Amino Acid Biosynthesis Pathways in Diatoms  

PubMed Central

Amino acids are not only building blocks for proteins but serve as precursors for the synthesis of many metabolites with multiple functions in growth and other biological processes of a living organism. The biosynthesis of amino acids is tightly connected with central carbon, nitrogen and sulfur metabolism. Recent publication of genome sequences for two diatoms Thalassiosira pseudonana and Phaeodactylum tricornutum created an opportunity for extensive studies on the structure of these metabolic pathways. Based on sequence homology found in the analyzed diatomal genes, the biosynthesis of amino acids in diatoms seems to be similar to higher plants. However, one of the most striking differences between the pathways in plants and in diatomas is that the latter possess and utilize the urea cycle. It serves as an important anaplerotic pathway for carbon fixation into amino acids and other N-containing compounds, which are essential for diatom growth and contribute to their high productivity. PMID:24957993

Bromke, Mariusz A.



Biosynthesis and Heterologous Production of Epothilones  

NASA Astrophysics Data System (ADS)

Although a variety of chemical syntheses for the epothilones and various derivatives have been described, modifying the backbone of those natural products remains a major challenge. One alternative to chemical alteration is the elucidation and subsequent manipulation of the biosynthetic pathway via genetic engineering in the producing organism. This type of approach is known as “combinatorial biosynthesis” and holds great promise, especially in conjunction with semi-synthesis methods to alter the structure of the natural product. In parallel, production can be optimized in the natural producer if the regulatory mechanisms governing the biosynthesis are understood. Alternatively, the entire gene cluster can be transferred into a heterologous host, more amenable both to genetic alteration and overexpression.

Müller, Rolf


Circular bacteriocins: biosynthesis and mode of action.  


Circular bacteriocins are a group of N-to-C-terminally linked antimicrobial peptides, produced by Gram-positive bacteria of the phylum Firmicutes. Circular bacteriocins generally exhibit broad-spectrum antimicrobial activity, including against common food-borne pathogens, such as Clostridium and Listeria spp. These peptides are further known for their high pH and thermal stability, as well as for resistance to many proteolytic enzymes, properties which make this group of bacteriocins highly promising for potential industrial applications and their biosynthesis of particular interest as a possible model system for the synthesis of highly stable bioactive peptides. In this review, we summarize the current knowledge on this group of bacteriocins, with emphasis on the recent progress in understanding circular bacteriocin genetics, biosynthesis, and mode of action; in addition, we highlight the current challenges and future perspectives for the application of these peptides. PMID:25172850

Gabrielsen, Christina; Brede, Dag A; Nes, Ingolf F; Diep, Dzung B



Preparation, co-assembling and interfacial crosslinking of photocurable and folate-conjugated amphiphilic block copolymers for controlled and targeted drug delivery: smart armored nanocarriers.  


Novel pH-sensitive, biodegradable and biocompatible copolymers based on polycaprolactone-poly(ethylene glycol) (PCL/PEG) were synthesized and further modified with folic acid and/or acryloyl chloride. The mixed polymeric micelles were formed by self-assembling of folated-copolymer and non-folated-copolymer with different compositions via nanoprecipitation method. The solubilization of quercetin as anti-cancer drug by the mixed micelle with the optimized composition (folated/non-folated 20/80) was more efficient than those made of each one alone. Nanogels with different crosslinking density were produced in the presence of ethylene glycol dimethacrylate (EGDMA) as the crosslinker via a photochemical method. Interfacial crosslinking of acrylated groups were utilized to produce a core-shell spherical nanoparticle to evaluate their in-vitro drug release and degradation rate. PMID:24374349

Khoee, Sepideh; Kavand, Alireza



Initiation of biosynthesis in cis polyisoprenes  

Microsoft Academic Search

The molecular species initiating rubber biosynthesis in leaves of Solidago altissima and Helianthus annuus and sporophores of Lactarius volemus have been analysed by structural characterization of the polyisoprenes by 13C NMR spectroscopy. The alignment of trans and cis isoprene units in these cis polyisoprenes has been determined using polyprenol-16 [dimethylallyl-(trans)2-(cis)13-OH] and ficaprenol-11 [dimethylallyl-(trans)3-(cis)7-OH], respectively, as model compounds. The C-1 methylene

Yasuyuki Tanaka; Seiichi Kawahara; Eng Aik-Hwee; Kenichi Shiba; Norimasa Ohya



Targeting NAD biosynthesis in bacterial pathogens  

US Patent & Trademark Office Database

The emergence of multidrug-resistant pathogens necessitates the search for new antibiotics acting on previously unexplored targets. Nicotinate mononucleotide adenylyltransferase of the NadD family, an essential enzyme of NAD biosynthesis in most bacteria, was selected as a target for structure-based inhibitor development. To this end, the inventors have identified small molecule compounds that inhibit bacterial target enzymes by interacting with a novel inhibitory binding site on the enzyme while having no effect on functionally equivalent human enzymes.



Biosynthesis of Gold Nanoparticles: A Review  

Microsoft Academic Search

\\u000a Many living and dead bacteria, cyanobacteria, and algae have the ability to produce gold nanoparticles with properties similar\\u000a to chemically synthesised materials. During the past two decades, the interaction of these microorganisms and two gold solutions\\u000a [gold(I)–thiosulfate and gold(III)–chloride] have been well investigated, although biosynthesis of gold nanoparticles is relatively\\u000a new. Intracellular synthesis of gold nanoparticles, as well as extracellular

Maggy F. Lengke; Charoen Sanpawanitchakit; Gordon Southam


Dual methylation pathways in lignin biosynthesis  

PubMed Central

Caffeoyl-coenzyme A (CoA) O-methyltransferase (CCoAOMT) has been proposed to be involved in an alternative methylation pathway of lignin biosynthesis. However, no direct evidence has been available to confirm that CCoAOMT is essential for lignin biosynthesis. To understand further the methylation steps in lignin biosynthesis, we used an antisense approach to alter O-methyltransferase (OMT) gene expression and investigated the consequences of this alteration. We generated transgenic tobacco plants with a substantial reduction in CCoAOMT as well as plants with a simultaneous reduction in both CCoAOMT and caffeic acid O-methyltransferase (CAOMT). Lignin analysis showed that the reduction in CCoAOMT alone resulted in a dramatic decrease in lignin content. The reduction in CCoAOMT also led to a dramatic alteration in lignin composition. Both guaiacyl lignin and syringyl lignin were reduced in the transgenic plants. However, guaiacyl lignin was preferentially reduced, which resulted in an increase in the S/G (syringl/guaiacyl) ratio. We have also analyzed lignin content and composition in transgenic plants having a simultaneous reduction in both CCoAOMT and CAOMT. The reduction in both OMTs resulted in a further decrease in total lignin content. This is in sharp contrast to the effect that resulted from the reduction in CAOMT alone, which only decreased the syringl lignin unit without a reduction in overall lignin content. These results unequivocally demonstrate that methylation reactions in lignin biosynthesis are catalyzed by both CCoAOMT and CAOMT. PMID:9836743

Zhong, R; III, WH; Negrel, J; Ye, ZH



Control of Arginine Biosynthesis in Pseudomonas aeruginosa  

Microsoft Academic Search

SUMMARY Arginine biosynthesis in Pseudoinonas aeruginosa proceeded via transacetylation of acetylornithine with glutamate ; it resembled Micrococcus glutamicus rather than Escherichia coli. Of four arginine biosynthetic enzymes, N-acetyl-y-glutamokinase, N-acetylornithine glutamate transacetylase, ornithine transcarbamylase and argininosuccinase determined under various conditions of arginine excess and deprivation, only ornithine transcarbamylase (OTCase) varied. It appeared to be fully derepressed in the wild-type strain grown




Thiamin Biosynthesis - still yielding fascinating biological chemistry  

PubMed Central

This paper will describe the biosynthesis of the thiamin thiazole in Bacillus subtilis and Saccharomyces cerevisiae. The two pathways are quite different: in B. subtilis, the thiazole is formed by an oxidative condensation of glycine, deoxy-D-xylulose- 5-phosphate and a protein thiocarboxylate, while in S. cerevisiae the thiazole is assembled from glycine, NAD and Cys205 of the thiazole synthase. PMID:22616866

Begley, Tadhg P.; Ealick, Steven E.; McLafferty, Fred W.



Phytosterol biosynthesis pathway in Mortierella alpina  

Microsoft Academic Search

The Zygomycetes fungus Mortierella alpina was cultured to growth arrest to assess the phytosterol biosynthesis pathway in a less-advanced fungus. The mycelium was found to produce 13 sterols, but no ergosterol. The sterol fractions were purified to homogeneity by HPLC and their identifies determined by a combination of GC–MS and 1H NMR spectroscopy. The principal sterol of the mycelium was

W. David Nes; Shawn D. Nichols



What happens to the microspherocytosis of hereditary spherocytosis in folate deficiency?  


The case is presented of an elderly man in whom hereditary spherocytosis (HS) had been diagnosed many years previously. He also had diverticulitis and was referred because of increasing anaemia (Hb 7.7 g/dl). He was suffering from diarrhoea and anorexia, and was taking a very poor diet. Serum investigations showed low folate and vitamin B12 levels. His blood film, despite the history of HS, showed very few spherocytes, and the red cell osmotic fragility curve was virtually normal. Instead, the blood film showed normocytes and oval macrocytes, mostly with normal central pallor. He was treated with vitamin B12 injections and folic acid tablets. On this treatment, the Hb rapidly rose, the macrocytosis disappeared, the film appearances reverted to the classical picture of HS with large numbers of microspherocytes, and the osmotic fragility curve to the picture of markedly increased fragility typical of HS. PMID:3250788

Blecher, T E



Poly(amidoamine) Dendrimer-Methotrexate Conjugates: The Mechanism of Interaction with Folate Binding Protein.  


Generation 5 poly(amidoamine) (G5 PAMAM) methotrexate (MTX) conjugates employing two small molecular linkers, G5-(COG-MTX)n, G5-(MFCO-MTX)n were prepared along with the conjugates of the G5-G5 (D) dimer, D-(COG-MTX)n, D-(MFCO-MTX)n. The monomer G5-(COG-MTX)n conjugates exhibited only a weak, rapidly reversible binding to folate binding protein (FBP) consistent with monovalent MTX binding. The D-(COG-MTX)n conjugates exhibited a slow onset, tight-binding mechanism in which the MTX first binds to the FBP, inducing protein structural rearrangement, followed by polymer-protein van der Waals interactions leading to tight-binding. The extent of irreversible binding is dependent on total MTX concentration and no evidence of multivalent MTX binding was observed. PMID:25222480

van Dongen, Mallory A; Rattan, Rahul; Silpe, Justin; Dougherty, Casey; Michmerhuizen, Nicole L; Van Winkle, Margaret; Huang, Baohua; Choi, Seok Ki; Sinniah, Kumar; Orr, Bradford G; Banaszak Holl, Mark M



Folate Receptor Alpha, Mesothelin and Megakaryocyte Potentiating Factor as Potential Serum Markers of Chronic Kidney Disease  

PubMed Central

Renal disease is the eighth leading cause of death in the United States. Early diagnosis is usually based on the detection of proteinuria or elevated serum creatinine, a relatively poor biomarker that does not accurately predict renal disease progression. As a result, more predictive biomarkers of renal function are sought. We present preliminary data on three protein biomarkers, folate receptor alpha (FRA), mesothelin (MSLN), and megakaryocyte potentiating factor (MPF), currently being pursued for applications in oncology diagnostics, and evaluate serum and urine levels in subjects with renal disease. Compared to healthy subjects, a significant (P < 0.0001) increase in all three biomarkers in both serum and urine of subjects with renal disease was demonstrated. Further, serum levels of these three protein biomarkers increased with increasing stage of disease suggesting their potential value in predicting progression in subjects with renal disease and raising caution in interpretation of data in oncology applications. PMID:24932099

Somers, Elizabeth B; O'Shannessy, Daniel J



118 SNPs of folate-related genes and risks of spina bifida and conotruncal heart defects  

PubMed Central

Background Folic acid taken in early pregnancy reduces risks for delivering offspring with several congenital anomalies. The mechanism by which folic acid reduces risk is unknown. Investigations into genetic variation that influences transport and metabolism of folate will help fill this data gap. We focused on 118 SNPs involved in folate transport and metabolism. Methods Using data from a California population-based registry, we investigated whether risks of spina bifida or conotruncal heart defects were influenced by 118 single nucleotide polymorphisms (SNPs) associated with the complex folate pathway. This case-control study included 259 infants with spina bifida and a random sample of 359 nonmalformed control infants born during 1983–86 or 1994–95. It also included 214 infants with conotruncal heart defects born during 1983–86. Infant genotyping was performed blinded to case or control status using a designed SNPlex assay. We examined single SNP effects for each of the 118 SNPs, as well as haplotypes, for each of the two outcomes. Results Few odds ratios (ORs) revealed sizable departures from 1.0. With respect to spina bifida, we observed ORs with 95% confidence intervals that did not include 1.0 for the following SNPs (heterozygous or homozygous) relative to the reference genotype: BHMT (rs3733890) OR = 1.8 (1.1–3.1), CBS (rs2851391) OR = 2.0 (1.2–3.1); CBS (rs234713) OR = 2.9 (1.3–6.7); MTHFD1 (rs2236224) OR = 1.7 (1.1–2.7); MTHFD1 (hcv11462908) OR = 0.2 (0–0.9); MTHFD2 (rs702465) OR = 0.6 (0.4–0.9); MTHFD2 (rs7571842) OR = 0.6 (0.4–0.9); MTHFR (rs1801133) OR = 2.0 (1.2–3.1); MTRR (rs162036) OR = 3.0 (1.5–5.9); MTRR (rs10380) OR = 3.4 (1.6–7.1); MTRR (rs1801394) OR = 0.7 (0.5–0.9); MTRR (rs9332) OR = 2.7 (1.3–5.3); TYMS (rs2847149) OR = 2.2 (1.4–3.5); TYMS (rs1001761) OR = 2.4 (1.5–3.8); and TYMS (rs502396) OR = 2.1 (1.3–3.3). However, multiple SNPs observed for a given gene showed evidence of linkage disequilibrium indicating that the observed SNPs were not individually contributing to risk. We did not observe any ORs with confidence intervals that did not include 1.0 for any of the studied SNPs with conotruncal heart defects. Haplotype reconstruction showed statistical evidence of nonrandom associations with TYMS, MTHFR, BHMT and MTR for spina bifida. Conclusion Our observations do not implicate a particular folate transport or metabolism gene to be strongly associated with risks for spina bifida or conotruncal defects. PMID:19493349

Shaw, Gary M; Lu, Wei; Zhu, Huiping; Yang, Wei; Briggs, Farren BS; Carmichael, Suzan L; Barcellos, Lisa F; Lammer, Edward J; Finnell, Richard H



Biosynthesis of salicylic acid in plants  

PubMed Central

Salicylic acid (SA) is an important signal molecule in plants. Two pathways of SA biosynthesis have been proposed in plants. Biochemical studies using isotope feeding have suggested that plants synthesize SA from cinnamate produced by the activity of phenylalanine ammonia lyase (PAL). Silencing of PAL genes in tobacco or chemical inhibition of PAL activity in Arabidopsis, cucumber and potato reduces pathogen-induced SA accumulation. Genetic studies, on the other hand, indicate that the bulk of SA is produced from isochorismate. In bacteria, SA is synthesized from chorismate through two reactions catalyzed by isochorismate synthase (ICS) and isochorismate pyruvate lyase (IPL). Arabidopsis contains two ICS genes but has no gene encoding proteins similar to the bacterial IPL. Thus, how SA is synthesized in plants is not fully elucidated. Two recently identified Arabidopsis genes, PBS3 and EPS1, are important for pathogen-induced SA accumulation. PBS3 encodes a member of the acyl-adenylate/thioester-forming enzyme family and EPS1 encodes a member of the BAHD acyltransferase superfamily. PBS3 and EPS1 may be directly involved in the synthesis of an important precursor or regulatory molecule for SA biosynthesis. The pathways and regulation of SA biosynthesis in plants may be more complicated than previously thought. PMID:19816125

Zheng, Zuyu; Huang, Junli; Lai, Zhibing; Fan, Baofang



Moss cell walls: structure and biosynthesis  

PubMed Central

The genome sequence of the moss Physcomitrella patens has stimulated new research examining the cell wall polysaccharides of mosses and the glycosyl transferases that synthesize them as a means to understand fundamental processes of cell wall biosynthesis and plant cell wall evolution. The cell walls of mosses and vascular plants are composed of the same classes of polysaccharides, but with differences in side chain composition and structure. Similarly, the genomes of P. patens and angiosperms encode the same families of cell wall glycosyl transferases, yet, in many cases these families have diversified independently in each lineage. Our understanding of land plant evolution could be enhanced by more complete knowledge of the relationships among glycosyl transferase functional diversification, cell wall structural and biochemical specialization, and the roles of cell walls in plant adaptation. As a foundation for these studies, we review the features of P. patens as an experimental system, analyses of cell wall composition in various moss species, recent studies that elucidate the structure and biosynthesis of cell wall polysaccharides in P. patens, and phylogenetic analysis of P. patens genes potentially involved in cell wall biosynthesis. PMID:22833752

Roberts, Alison W.; Roberts, Eric M.; Haigler, Candace H.



Folate deficiency  


... Eating an unhealthy diet that not include enough fruits and vegetables ... people in the United States eat enough folic acid because it is ... fruits and juices Dark green leafy vegetables Liver Poultry, ...


A human membrane-associated folate binding protein is anchored by a glycosyl-phosphatidylinositol tail.  


Membrane-associated and soluble forms of folate binding protein (FBP) have been identified in mammalian tissues and biological fluids. Despite their solubility differences, these two forms are functionally similar, immunologically cross-reacting, and have the same apparent molecular weights. In this study we demonstrate, for the first time, that the membrane FBP of cultured human KB cells contains a glycosyl-phosphatidylinositol (GPI) tail which is responsible for its hydrophobic properties and distinguishes it from the soluble FBP released into the medium. Treatment of the purified membrane FBP with phospholipase C specific for phosphatidylinositol (PI-PLC) removed the GPI tail and converted it to the soluble form without a change in apparent Mr by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. In addition, virtually all of the folate binding sites on the plasma membrane of the intact cells were released as soluble, functional FBP following treatment with PI-PLC. The GPI tail contained 1-O-alkyl-2-O-acylglycerol as a mixture of fatty alcohols in ether linkage at C1 of the glycerol backbone and almost exclusively docosanoic acid (22:0) as the fatty acid on C2. The inositol also contained a mixture of fatty acids (16:0, 18:0, 18:1, 20:4, 22:0) located on a site other than the C2 position since the FBP was susceptible to PI-PLC cleavage. After nitrous acid deamination, the aqueous portion of the FBP contained covalently bound fatty acids, predominantly palmitate (16:0) and stearate (18:0), indicating the presence of additional acyl groups attached to the peptide in the form of amide, ester, or thioester linkage. PMID:2557328

Luhrs, C A; Slomiany, B L



Avidity Modulation of Folate-Targeted Multivalent Dendrimers for Evaluating Biophysical Models of Cancer Targeting Nanoparticles  

PubMed Central

We investigated two types of generation 5 polyamidoamine (PAMAM) dendrimers, each conjugated stochastically with a mean number of five or ten methotrexate (MTX) ligands per dendrimer (G5-MTX5, G5-MTX10), for their binding to surface-immobilized folate binding protein (FBP) as a function of receptor density. The binding study was performed under flow by surface plasmon resonance spectroscopy. Two multivalent models were examined to simulate binding of the dendrimer to the receptor surface, showing that at relatively high receptor density, both dendrimer conjugates exhibit high avidity. However, upon reducing the receptor density by a factor of three and thirteen relative to the high density level, the avidity of the lower-valent G5-MTX5 decreases by up to several orders of magnitude (KD = nM to ?M), whereas the avidity of G5-MTX10 remains largely unaffected regardless of the density variation. Notably, on the 13-fold reduced FBP surface, G5-MTX5 displays binding kinetics similar to that of monovalent methotrexate, which is patently different from the still tight binding of the higher-valent G5-MTX10. Thus, the binding analysis demonstrates that avidity displayed by multivalent MTX conjugates varies in response to the receptor density, and it can be modulated for achieving tighter, more specific binding to the higher receptor density by modulation of ligand valency. We believe this study provides experimental evidence supportive of the mechanistic hypothesis of multivalent NP uptake to a cancer cell over a healthy cell where the diseased cell expresses the folate receptor at higher density. PMID:23855478

Silpe, Justin E.; Sumit, Madhuresh; Thomas, Thommey P.; Huang, Baohua; Kotlyar, Alina; van Dongen, Mallory A.; Banaszak Holl, Mark M.; Orr, Bradford G.; Choi, Seok Ki



Polymorphisms in folate-related genes and risk of pediatric acute lymphoblastic leukemia.  


Polymorphisms in folate pathway genes may influence the susceptibility to acute lymphoblastic leukemia (ALL). DNA was isolated from 245 pediatric ALL patients (cases) and from 500 blood bank donors (controls). Polymorphisms in methylene-tetrahydrofolate reductase (MTHFR 677C>T, 1298A>C), methionine synthase (MTR 2756A>G), methionine synthase reductase (MTRR 66A>G), methylenetetrahydrofolate dehydrogenase (MTHFD1 1958G>A), nicotinamide N-methyltransferase (NNMT IVS -151C>T), serine hydroxymethyl transferase (SHMT1 1420C>T), thymidylate synthase (TS 2R3R), and the reduced folate carrier (RFC1 80G>A) were detected. In ALL patients, an increased occurrence was observed of the RFC1 80AA variant (odds ratio [OR] = 2.1; 95% confidence interval [CI] = 1.3-3.2; P = .002) and the RFC1 80A allele (OR = 1.5; 95% CI, 1.1-2.1; P = .02). Likewise, the NNMT IVS -151TT genotype showed a 2.2-fold increased ALL risk (OR = 2.2; 95% CI, 1.1-4.6; P = .04). A 1.4-fold reduction in ALL risk was observed for (heterozygous or homozygous) carriers of the TS 2R allele and the MTHFR 677T allele (OR = 0.7; 95% CI, 0.5-1.0; P < .05). Furthermore, interactions between NNMT and MTHFR 677C>T and RFC1 were observed. NNMT IVS -151CC/MTHFR 677CT + TT patients exhibited a 2-fold reduction in ALL risk whereas RFC1 80AA/NNMT IVS -151CT + TT subjects had a 4.2-fold increase in ALL risk (P = .001). For the first time, we associate the RFC1 80G>A and NNMT IVS -151C>T variants to an increased ALL susceptibility. PMID:19020309

de Jonge, Robert; Tissing, Wim J E; Hooijberg, Jan Hendrik; Jansen, Gerrit; Kaspers, Gertjan J L; Lindemans, Jan; Peters, Godefridus J; Pieters, Rob



Folate deprivation reduces homocysteine remethylation in a human intestinal epithelial cell culture model: role of serine in one-carbon donation.  


Little is known about homocysteine metabolism in intestine. To address this question, we investigated homocysteine metabolism under conditions of folate adequacy and folate deprivation in the Caco-2 cell line, a model of human intestinal mucosal cells. Caco-2 cells were cultured in media enriched with [3-(13)C]serine and [U-(13)C(5)]methionine tracers, and enrichments of intracellular free amino acid pools of these amino acids as well as homocysteine, cystathionine, and cysteine were measured by using gas chromatography/mass spectrometry. Homocysteine transsulfuration plus folate-dependent and total remethylation were quantified from these amino acid enrichments. Homocysteine remethylation accounted for 19% of the intracellular free methionine pool in cells cultured with supplemental folate, and nearly all one-carbon units used for remethylation originated from the three carbon of serine via folate-dependent remethylation. Labeling of cystathionine and cysteine indicated the presence of a complete transsulfuration pathway in Caco-2 cells, and this pathway produced 13% of the intracellular free cysteine pool. Appearance of labeled homocysteine and cystathionine in culture medium suggests export of these metabolites from intestinal cells. Remethylation was reduced by one-third in folate-restricted cell cultures (P < 0.001), and only approximately 50% of the one-carbon units used for remethylation originated from the three carbon of serine under these conditions. In conclusion, the three carbon of serine is the primary source of one-carbon units used for homocysteine remethylation in folate-supplemented Caco-2 cell cultures. Remethylation is reduced as a result of folate restriction in this mucosal cell model, and one-carbon sources other than the three carbon of serine contribute to remethylation under this condition. PMID:14615285

Townsend, Justin H; Davis, Steven R; Mackey, Amy D; Gregory, Jesse F



Involvement of gene polymorphisms of the folate pathway enzymes in gene expression and anticancer drug sensitivity using the NCI60 panel as a model  

Microsoft Academic Search

Folate, a vitamin of the B group involved in one-carbon group metabolism, plays an important role in DNA synthesis and methylation. Several polymorphisms in the genes involved in folate uptake and biotransformations have been shown to be associated to the risk of cancer and to anticancer drug response. We studied common polymorphisms in MTHFR (N5,10-methylene-tetrahydrofolate reductase), MTHFD1 (N5,10-methylene-tetrahydrofolate dehydrogenase), MTR

Virginie Charasson; Dominique Hillaire-Buys; Isabelle Solassol; Armelle Laurand-Quancard; Frédéric Pinguet; Valérie Le Morvan; Jacques Robert



Serum homocysteine, folate and vitamin B 12 in patients with Paget’s disease of bone: the effect of zoledronic acid  

Microsoft Academic Search

High serum homocysteine (HCY) and indirectly deficiency of folate and\\/or vitamin B12 stimulate bone resorption and adversely affect collagen cross-linking. The aim of this study was the evaluation of serum\\u000a levels of HCY, folate and vitamin B12 in patients with Paget’s disease of bone (PDB) and the effect of zoledronic acid (ZOL) on their serum levels. Nine consecutive\\u000a patients with

Stergios A. PolyzosAthanasios; Athanasios D. Anastasilakis; Zoe Efstathiadou; Ioannis Litsas; Marina Kita; Athanasios Panagiotou; Athanasios Papatheodorou; Georgios Arsos; Efstratios Moralidis; Georgios Barmpalios; Efthimia Zafeiriadou; Efthimia Triantafillidou; Eleni Makrigiannaki; Evangelos Terpos



Socioeconomic factors are associated with folate and vitamin B12 intakes and related biomarkers concentrations in European adolescents: the Healthy Lifestyle in Europe by Nutrition in Adolescence study.  


Because socioeconomic factors (SEFs) may influence dietary quality and vitamin intakes, this study aimed to examine associations between socioeconomic factors and folate and vitamin B12 intakes as well as their related biomarkers in the Healthy Lifestyle in Europe by Nutrition in Adolescence study. Vitamin intakes were obtained from two 24-hour recalls in 2253 participants (47% males). Vitamin B biomarkers were assessed in a subsample of 977 participants (46% males). Socioeconomic factors were assessed by questionnaire, and 1-way analysis of covariance and linear regression analysis were applied. For males and females, mean intakes of folate were 211.19 and 177.18 ?g/d, and for vitamin B12, 5.98 and 4.54 ?g/d, respectively. Levels of plasma folate, red blood cell folate, serum B12, and holotranscobalamin were 18.74, 807.19, 330.64, and 63.04 nmol/L in males, respectively, and 19.13, 770.16, 377.9, and 65.63 nmol/L in females, respectively. Lower folate intakes were associated with several SEFs, including maternal and paternal education in both sexes. Regarding folate biomarkers, lower plasma folate intakes were associated with single/shared care in males and with lower paternal occupation in females. Lower vitamin B12 intakes were associated with almost all the studied SEFs, except paternal occupation in both sexes. In females, when considering vitamin B12 biomarkers, lower plasma vitamin B12 was associated with lower maternal education and occupation, and lower holotranscobalamin was associated with lower maternal education and lower paternal occupation. In conclusion, from the set of socioeconomic determinants studied in a sample of European adolescents, maternal education and paternal occupation were more consistently associated with folate and vitamin B12 intakes and biomarkers concentrations. PMID:24655486

Iglesia, Iris; Mouratidou, Theodora; González-Gross, Marcela; Novakovic, Romana; Breidenassel, Christina; Jiménez-Pavón, David; Huybrechts, Inge; De Henauw, Stefaan; Geelen, Anouk; Gottrand, Frédéric; Kafatos, Anthony; Mistura, Lorenza; de Heredia, Fátima Pérez; Widhalm, Kurt; Manios, Yanis; Molnar, Denes; Stehle, Peter; Gurinovic, Mirjana; Cavelaars, Adrienne E J M; Van't Veer, Pieter; Moreno, Luis A



Plasma 25-hydroxyvitamin D3, folate and vitamin B12 biomarkers among international colorectal cancer patients: a pilot study.  


Vitamin D and folate are associated with decreased colorectal cancer risk and their association with colorectal cancer prognosis is under investigation. We assessed the levels of plasma 25-hydroxyvitamin D3 (25(OH)D3), folate and vitamin B12 in an international pilot study in order to determine variability of these biomarkers based on geographical location. Plasma 25(OH)D3, folate and vitamin B12 concentrations were measured in 149 invasive, newly diagnosed colorectal cancer cases from Heidelberg (Germany), Seattle (WA, USA), and Tampa (FL, USA) and in ninety-one age- and sex-matched controls. Their associations with potential predictors were assessed using multivariate linear regression analyses. Plasma 25(OH)D3, folate and vitamin B12 concentrations differed by location. Other predictors were season for 25(OH)D3 and tumour stage (vitamin B12). Season-corrected average 25(OH)D3 concentrations were higher in Heidelberg (31·7 ng/ml; range 11·0-83·0 ng/ml) than in Seattle (23·3 ng/ml; range 4·0-80·0 ng/ml) and Tampa (21·1 ng/ml; range 4·6-51·6 ng/ml). In Heidelberg, a strong seasonal variation was observed. Folate (11·1 ng/ml) and vitamin B12 (395 pg/ml) concentrations in Heidelberg were lower than those in Seattle (25·3 ng/ml and 740 pg/ml, respectively) and Tampa (23·8 ng/ml and 522 pg/ml, respectively). Differences in plasma 25(OH)D3 and folate concentrations between Heidelberg and the US sites were observed, probably reflecting variation in outdoor activities and sun-avoidance behaviour during summer as well as in folic acid fortification and supplement use. Intra-site differences at each study location were greater than between-location variability, suggesting that individual health behaviours play a significant role. Nevertheless, the intra-site differences we observed may be due to chance because of the limited sample size. Our pilot study illustrates the value of an international cohort in studying colorectal cancer prognosis to discern geographical differences in a broad range of exposures. PMID:25191595

Ulrich, Cornelia M; Toriola, Adetunji T; Siegel, Erin M; Brenner, Hermann; Chang-Claude, Jenny; Abbenhardt, Clare; Kotzmann, Jana; Song, Xiaoling; Owen, Robert W; Hoffmeister, Michael; Becher, Heiko; Shibata, David; Vickers, Kathy; Rush, Shannon K; Makar, Karen; Würtele, Gerd; Haubner, Roswitha; Sellers, Thomas A; Grady, William



Identification of the folate binding sites on the Escherichia coli T-protein of the glycine cleavage system.  


T-protein is a component of the glycine cleavage system and catalyzes the tetrahydrofolate-dependent reaction. To determine the folate-binding site on the enzyme, 14C-labeled methylenetetrahydropteroyltetraglutamate (5,10-CH2-H4PteGlu4) was enzymatically synthesized from methylenetetrahydrofolate (5, 10-CH2-H4folate) and [U-14C]glutamic acid and subjected to cross-linking with the recombinant Escherichia coli T-protein using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, a zero-length cross-linker between amino and carboxyl groups. The cross-linked product was digested with lysylendopeptidase, and the resulting peptides were separated by reversed-phase high performance liquid chromatography. Amino acid sequencing of the labeled peptides revealed that three lysine residues at positions 78, 81, and 352 were involved in the cross-linking with polyglutamate moiety of 5, 10-CH2-H4PteGlu4. The comparable experiment with 5,10-CH2-H4folate revealed that Lys-81 and Lys-352 were also involved in cross-linking with the monoglutamate form. Mutants with single or multiple replacement(s) of these lysine residues to glutamic acid were constructed by site-directed mutagenesis and subjected to kinetic analysis. The single mutation of Lys-352 caused similar increase (2-fold) in Km values for both folate substrates, but that of Lys-81 affected greatly the Km value for 5,10-CH2-H4PteGlu4 rather than for 5,10-CH2-H4folate. It is postulated that Lys-352 may serve as the primary binding site to alpha-carboxyl group of the first glutamate residue nearest the p-aminobenzoic acid ring of 5,10-CH2-H4folate and 5,10-CH2-H4PteGlu4, whereas Lys-81 may play a key role to hold the second glutamate residue through binding to alpha-carboxyl group of the second glutamate residue. PMID:10364177

Okamura-Ikeda, K; Fujiwara, K; Motokawa, Y