Microbiological assay of folates in 96-well microtiter plates

Horne, Donald W.

doi:10.1016/s0076-6879(97)81006-3

Cited by 89 publications

(87 citation statements)

References 7 publications

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“…For quantification of breast folate, a microbiological microtiter plate assay using Lactobacillus casei was used as previously described. 63 Briefly, 10-20 mg of breast tissues were homogenized with folate extraction buffer (2% sodium ascorbate, 2% Bis-Tris, and 0.07% 2-mercaptoethanol). The mixtures were immersed in boiling water (20 minutes), cooled on ice, and then centrifuged at 36,000g (20 minutes; 4 C).…”

Section: Plasma and Breast Folate Analysismentioning

confidence: 99%

Associations between genetic variation in one-carbon metabolism and LINE-1 DNA methylation in histologically normal breast tissues

Llanos

Marian²,

Brasky

et al. 2015

Epigenetics

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Genome-wide DNA hypomethylation is an early event in the carcinogenic process. Percent methylation of long interspersed nucleotide element-1 (LINE-1) is a biomarker of genome-wide methylation and is a potential biomarker for breast cancer. Understanding factors associated with percent LINE-1 DNA methylation in histologically normal tissues could provide insight into early stages of carcinogenesis. In a cross-sectional study of 121 healthy women with no prior history of cancer who underwent reduction mammoplasty, we examined associations between plasma and breast folate, genetic variation in one-carbon metabolism, and percent LINE-1 methylation using multivariable regression models (adjusting for race, oral contraceptive use, and alcohol use). Results are expressed as the ratio of LINE-1 methylation relative to that of the referent group, with the corresponding 95% confidence intervals (CI). We found no significant associations between plasma or breast folate and percent LINE-1 methylation. Variation in MTHFR, MTR, and MTRR were significantly associated with percent LINE-1 methylation. Variant allele carriers of MTHFR A1289C had 4% lower LINE-1 methylation (Ratio 0.96, 95% CI 0.93-0.98), while variant allele carriers of MTR A2756G (Ratio 1.03, 95% CI 1.01-1.06) and MTRR A66G (Ratio 1.03, 95% CI 1.01-1.06) had 3% higher LINE-1 methylation, compared to those carrying the more common genotypes of these SNPs. DNA methylation of LINE-1 elements in histologically normal breast tissues is influenced by polymorphisms in genes in the one-carbon metabolism pathway. Future studies are needed to investigate the sociodemographic, environmental and additional genetic determinants of DNA methylation in breast tissues and the impact on breast cancer susceptibility.

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Section: Plasma and Breast Folate Analysismentioning

confidence: 99%

Associations between genetic variation in one-carbon metabolism and LINE-1 DNA methylation in histologically normal breast tissues

Llanos

Marian²,

Brasky

et al. 2015

Epigenetics

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“…The Swiss Vitamin Institute analysed plasma samples from WRA for folate concentrations using the microbiological assay and Lactobacillus caseii ATCC 7469 (20) . On a sub-sample (random selection of half of the samples), vitamin B 12 was analysed using the same method but working with Lactobacillus leichmanii (ATCC 7830).…”

Section: Blood Sampling and Analysismentioning

confidence: 99%

Prevalence and public health relevance of micronutrient deficiencies and undernutrition in pre-school children and women of reproductive age in Côte d'Ivoire, West Africa

Rohner

Northrop-Clewes

Tschannen

et al. 2013

Public Health Nutr.

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Objective: To provide nationally representative data on the prevalence of anaemia, vitamin A and Fe deficiencies among pre-school age children (pre-SAC) and nonpregnant women of reproductive age (WRA), and on vitamin B 12 and folate deficiencies in WRA, and the influence of inflammation on their interpretation. Design: A cross-sectional survey to measure anthropometry, malaria parasitaemia and micronutrient status. Specifically, blood samples were analysed for Hb, plasma ferritin, soluble transferrin receptors, C-reactive protein, a 1 -acid glycoprotein, retinol-binding protein, vitamin B 12 and folate. Setting: Côte d'Ivoire in 2007. Subjects: Nine hundred and twenty-eight WRA and 879 pre-SAC. Results: In WRA, prevalence of Plasmodium parasitaemia (5 %) was low, but inflammation (34 %) was higher. Anaemia was a severe public health problem and prevalence differed by residency and eco-region. Inflammation-adjusted Fe deficiency was highest in urban areas (20 %). Nationally, folate deficiency was 86 %, higher in urban areas and varied by eco-region. Prevalence of vitamin B 12 deficiency was low but higher in the rural areas and the north. Inflammationadjusted vitamin A deficiency was very low (1 %). In pre-SAC, prevalence of inflammation (67 %) and Plasmodium parasites (25 %) was high; the latter was associated with poverty, rural residency and higher ferritin concentrations. Anaemia was classified as a severe public health problem (72 %), and was higher in rural areas (76 %) and the north (87 %). A quarter of pre-SAC suffered from vitamin A deficiency (inflammation-adjusted) and prevalence of undernutrition was high. Conclusions: Prevalence of inflammation, Plasmodium parasitaemia and micronutrient deficiencies were high in Côte d'Ivoire, particularly in pre-SAC. Nutritional interventions should be accompanied by strategies to reduce exposure to infections.

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“…The folate content was assayed by using Lactobacillus casei method as described [27]. The protein samples were mixed with 10 volumes of extraction buffer (50 mM HEPES, 50 mM CHES, pH 7.85, 18 mM β-mercaptoethanol, 2% ascorbate) and heated for 10 min in a boiling water bath.…”

Section: Folate Assaymentioning

confidence: 99%

“…The protein samples were mixed with 10 volumes of extraction buffer (50 mM HEPES, 50 mM CHES, pH 7.85, 18 mM β-mercaptoethanol, 2% ascorbate) and heated for 10 min in a boiling water bath. Precipitated proteins were separated by centrifugation and the supernatant was treated with conjugase prepared from rat for 3 hours at +37° C [27]. Reaction mixtures were boiled again, centrifuged and the supernatant was used for analysis.…”

Section: Folate Assaymentioning

confidence: 99%

Acetylation of N-terminal valine of glycine N-methyltransferase affects enzyme inhibition by folate

Luka

Loukachevitch

Wagner

2008

Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics

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SummaryNative liver glycine N-methyltransferase is N-acetylated while the recombinant enzyme is not. We show here that acetylation of the N-terminal valine affects several of kinetic parameters of the enzyme. Glycine N-methyltransferase is a regulatory enzyme mediating the availability of methyl groups by virtue of being inhibited by folate. N-acetylation does not affect the overall structure of the protein and does not affect basal enzyme activity of GNMT. Binding of both the mono-and pentaglutamate forms of 5-methyltetrahydrofolate is the same for the acetylated and non-acetylated forms of the enzyme, however the pentaglutamate form is bound more tightly than the monoglutamate form in both cases. Although binding of the folates are similar for the acetylated and non-acetylated forms of the enzyme, inhibition of enzyme activity differs significantly. The native, N-acetylated form of the enzyme shows 50% inhibition at 1.3 µM concentration of the pentaglutamate while the recombinant non-acetylated form shows 50% inhibition at 590 µM. In addition, the binding of folate results in cooperativity of the substrate, AdoMet, with a Hill coefficient of 1.5 for 5-methyltetrahydrofolate pentaglutamate.

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Microbiological assay of folates in 96-well microtiter plates

Cited by 89 publications

References 7 publications

Associations between genetic variation in one-carbon metabolism and LINE-1 DNA methylation in histologically normal breast tissues

Associations between genetic variation in one-carbon metabolism and LINE-1 DNA methylation in histologically normal breast tissues

Prevalence and public health relevance of micronutrient deficiencies and undernutrition in pre-school children and women of reproductive age in Côte d'Ivoire, West Africa

Acetylation of N-terminal valine of glycine N-methyltransferase affects enzyme inhibition by folate

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