L-methionine, also known as L-aminomethane, is one of the eight essential amino acids required by the human body and has important applications in the fields of feed, medicine, and food. In this study, an L-methionine high-yielding strain was constructed using a modular metabolic engineering strategy based on the M2 strain (Escherichia coli W3110 ΔIJAHFEBC/PAM) previously constructed in our laboratory. Firstly, the production of one-carbon module methyl donors was enhanced by overexpression of methylenetetrahydrofolate reductase (methylenetetrahydrofolate reductase, MetF) and screening of hydroxymethyltransferase (GlyA) from different sources, optimizing the one-carbon module. Subsequently, cysteamine lyase (hydroxymethyltransferase, MalY) and cysteine internal transporter gene (fliY) were overexpressed to improve the supply of L-homocysteine and L-cysteine, two precursors of the one-carbon module. The production of L-methionine in shake flask fermentation was increased from 2.8 g/L to 4.05 g/L, and up to 18.26 g/L in a 5 L fermenter. The results indicate that the one carbon module has a significant impact on the biosynthesis of L-methionine, and efficient biosynthesis of L-methionine can be achieved through optimizing the one carbon module. This study may facilitate further improvement of microbial fermentation production of L-methionine.
Humans ; Methionine ; Methylenetetrahydrofolate Reductase (NADPH2) ; Carbon ; Cysteine ; Escherichia coli/genetics* ; Hydroxymethyl and Formyl Transferases ; Carrier Proteins ; Escherichia coli Proteins

To investigate the expression of small dense low-density lipoprotein cholesterol (sdLDL-C) in patients with H-type hypertension and its association with H-type hypertension and methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms. The retrospective study method was used,and a total of 207 hospitalized hypertensive patients (76 males and 131 females, aged 40-82 years, median age 66 years) admitted to the Zibo First Hospital from March 2021 to March 2022 were enrolled in this study. The levels of homocysteine (Hcy), sdLDL-C, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), total cholesterol (TC), triglyceride (TG) and lipoprotein (a) [Lp(a)] were measured. The patients were divided into H-type hypertensive group (n=105, 40 males and 65 females) and non-H-type hypertensive group (n=102, 36 males and 66 females) according to Hcy levels. The C677T polymorphism of methylenetetrahydrofolate reductase (MTHFR) gene was detected in each group. Logistic regression analysis was performed for the related factors of H-type hypertension. The serum sdLDL-C levels were (0.92±0.31) and (0.65±0.28) mmol/L in H-type hypertension group and non-H-type hypertension group, respectively. The sdLDL-C levels in H-type hypertension group were significantly higher than those in non-H-type hypertension group (t=6.500, P<0.01). There was no significant difference in the serum sdLDL-C levels between males and females in H-type hypertension group (t=-1.543, P=0.129). The CC, CT, TT genotypes and C and T allele frequencies of MTHFR C677T in H-type hypertension group were significantly different from those in non-H-type hypertension group (P<0.05). The Hcy and sdLDL-C levels in different genotypes of MTHFR in H-type hypertension group were significantly different (H=12.742, P=0.002; F=3.345, P=0.042). Among them, Hcy levels were higher in TT genotype than in CT and CC genotypes, respectively (Z=-28.099, P=0.003; Z=-16.112, P=0.040), and sdLDL-C levels were higher in TT genotype than in CC genotype (t=-2.587, P=0.012). Logistic regression analysis showed that age, sdLDL-C, and MTHFRC677T TT genotypes were associated with the development for H-type hypertension. In conclusion, the level of sdLDL-C is associated with MTHFR gene polymorphisms and may be associated with the development of H-type hypertension.
Male ; Female ; Humans ; Aged ; Methylenetetrahydrofolate Reductase (NADPH2)/genetics* ; Cholesterol, LDL/genetics* ; Retrospective Studies ; Polymorphism, Genetic ; Gene Frequency ; Genotype ; Hypertension ; Homocysteine/genetics*

BACKGROUND: Excessive exposure to fluoride can reduce intelligence. Methylenetetrahydrofolate dehydrogenase, cyclohydrolase, and formyltetrahydrofolate synthetase 1 ( MTHFD1 ) polymorphisms have important roles in neurodevelopment. However, the association of MTHFD1 polymorphisms with children's intelligence changes in endemic fluorosis areas has been rarely explored. METHODS: A cross-sectional study was conducted in four randomly selected primary schools in Tongxu County, Henan Province, from April to May in 2017. A total of 694 children aged 8 to 12 years were included in the study with the recruitment by the cluster sampling method. Urinary fluoride (UF) and urinary creatinine were separately determined using the fluoride ion-selective electrode and creatinine assay kit. Children were classified as the high fluoride group and control group according to the median of urinary creatinine-adjusted urinary fluoride (UF Cr ) level. Four loci of MTHFD1 were genotyped, and the Combined Raven's Test was used to evaluate children's intelligence quotient (IQ). Generalized linear model and multinomial logistic regression model were performed to analyze the associations between children's UF Cr level, MTHFD1 polymorphisms, and intelligence. The general linear model was used to explore the effects of gene-environment and gene-gene interaction on intelligence. RESULTS: In the high fluoride group, children's IQ scores decreased by 2.502 when the UF Cr level increased by 1.0 mg/L (β = -2.502, 95% confidence interval [CI]:-4.411, -0.593), and the possibility for having "excellent" intelligence decreased by 46.3% (odds ratio = 0.537, 95% CI: 0.290, 0.994). Children with the GG genotype showed increased IQ scores than those with the AA genotype of rs11627387 locus in the high fluoride group ( P   <  0.05). Interactions between fluoride exposure and MTHFD1 polymorphisms on intelligence were observed (Pinteraction < 0.05). CONCLUSION Our findings suggest that excessive fluoride exposure may have adverse effects on children's intelligence, and changes in children's intelligence may be associated with the interaction between fluoride and MTHFD1 polymorphisms.
Child ; Creatinine ; Cross-Sectional Studies ; Fluorides/urine* ; Formate-Tetrahydrofolate Ligase ; Humans ; Intelligence/genetics* ; Methylenetetrahydrofolate Dehydrogenase (NADP) ; Methylenetetrahydrofolate Reductase (NADPH2)

OBJECTIVE: To assess the association of C677T polymorphism of methylenetetrahydrofolate reductase (MTHFR) gene with autistic behavior and inheritance pattern of children patients. METHODS: Ninety three autism patients were selected as the study group, whilst 93 healthy children were selected as the control group. The C677T genotype of the MTHFR gene was determined, and the correlation between the genotype and the autistic behavior and inheritance pattern were investigated. RESULTS: MTHFR gene C677T locus revealed three genotypes CC, CT and TT. Compared with the control group, the study group had fewer CC genotype but more TT genotype (P<0.05). Individuals with the three genotypes showed a statistically significant difference in the frequencies of four problem behaviors (P<0.05). Regression analysis showed that at least one T allele encoding the degree of 1 and 2 for the 4 problem behaviors that were statistically different. MTHFR gene C677T genotype was associated with autism under the recessive inheritance model and allelic inheritance model (P<0.05). CONCLUSION The C677T polymorphism of the MTHFR gene is associated with autistic behaviors. Children with the TT genotype or T allele are at higher risk of developing autism, particularly direct gaze, complex limb movements, self-injurious behavior and hyperactivity 1 and 2 related with the degree of coding.
Autistic Disorder/genetics* ; Child ; Genetic Predisposition to Disease ; Genotype ; Humans ; Inheritance Patterns ; Methylenetetrahydrofolate Reductase (NADPH2)/genetics* ; Problem Behavior

OBJECTIVES: To study the distribution characteristics of methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism in children with primary hypertension, and to explore the association between MTHFR C677T gene polymorphism and H-type hypertension in children. METHODS: A total of 121 children with primary hypertension who were hospitalized in the department of cardiovascular medicine from January to July 2021, newly diagnosed, and untreated were retrospectively selected as the subjects. The children were divided into three groups: CC genotype (19 children), CT genotype (51 children), and TT genotype (51 children). According to the serum homocysteine (Hcy) level, they were divided two groups: H-type hypertension (47 children) and simple hypertension (74 children). The medical data were compared between the groups. The association between MTHFR C677T gene polymorphism and H-type hypertension was evaluated. RESULTS: The mutation frequency of T allele in children with primary hypertension was significantly higher than that in healthy adults in Beijing and Chinese Han adults (P<0.001). The serum Hcy level in the TT genotype group was significantly higher than that in the CC and CT genotype groups (P<0.001). The serum Hcy level in the H-type hypertension group was significantly higher than that in the simple hypertension group (P<0.001), and MTHFR C677T was mostly TT genotype, which was associated with the risk of H-type hypertension (OR=12.71, P<0.001). There was no significant difference in the incidence rate of target organ damage between the H-type hypertension and simple hypertension groups (P>0.05). However, multiple organ involvement was observed in the H-type hypertension group at diagnosis, accounting for 11% (5/47). CONCLUSIONS The mutation rate of MTHFR C677T T allele in children with primary hypertension is high and associated with the serum Hcy level. TT genotype is an independent risk factor for H-type hypertension in children, and it may be related to the severity of early target organ damage.
Alleles ; Child ; Genotype ; Humans ; Hypertension/genetics* ; Methylenetetrahydrofolate Reductase (NADPH2)/genetics* ; Polymorphism, Genetic ; Retrospective Studies

OBJECTIVE: To observe the expression level of serum homocysteine (Hcy) and methylenetetrahydrofolate reductase (MTHFR) gene polymorphism in patients with hematological diseases complicated with coronary heart disease, and analyze the relationship between serum Hcy level, MTHFR gene polymorphism and coronary heart disease. METHODS: The medical records of 80 patients with coronary heart disease who completed treatment of hematological diseases during the period from March 2018 to March 2020 were selected as observation group. In addition, the medical records of 92 patients with hematological diseases who completed treatment in our hospital during the same period were selected as control group. Venous blood samples of the two groups were collected to detect serum Hcy level and MTHFR gene polymorphism. The serum Hcy levels of the two groups with different MTHFR genotypes were compared, and the effects of the above indicators on hematological diseases complicated with coronary heart disease were analyzed. RESULTS: The detection rates of MTHFR gene TT and TC in the observation group were higher than those in the control group, while the distribution frequency of MTHFR genotype CC was lower (P<0.05). The serum Hcy levels of the patients with MTHFR genotype TT and TC in the observation group was higher than the control group (P<0.05). Binary logistic regression analysis showed that MTHFR gene TC/CC genotype serum Hcy overexpression may be influencing factor which induced coronary heart disease in patients with hematological diseases (OR=2.107/OR=1.634, P<0.05). ROC curves showed that the AUC of serum Hcy level of MTHFR gene TC/CC genotype and hematological disease complicated with coronary heart disease were both > 0.8. When MTHFR gene TC reaching the optimal threshold of 22.165 μmol/L, the sensitivity was 0.950 and the specificity was 0.837, While MTHFR gene CC reached the optimal threshold of 19.630 μmol/L, the sensitivity was 0.938 and the specificity was 0.826, the best predictive value could be obtained. CONCLUSION The changes of serum Hcy and MTHFR gene polymorphisms may be involved in the pathological process in patients with hematological diseases complicated with coronary heart disease. In the future, early detection of serum Hcy levels and MTHFR gene polymorphisms in patients with hematological diseases can be used to predict the risk of coronary heart disease.
Coronary Disease/genetics* ; Genotype ; Hematologic Diseases/complications* ; Homocysteine ; Humans ; Methylenetetrahydrofolate Reductase (NADPH2)/genetics* ; Polymorphism, Genetic

Alleles ; Asthma/genetics* ; Child ; Genetic Predisposition to Disease ; Genotype ; Glucocorticoids ; Humans ; Methylenetetrahydrofolate Reductase (NADPH2)/genetics* ; Polymorphism, Genetic

Objective To investigate the association between the methylenetetrahydrofolate reductase gene C677T (MTHFR C677T) polymorphism and diabetic retinopathy (DR). Methods A total of 6971 subjects including 2707 DR patients and 4264 controls from 23 studies were enrolled in the study. A random-effects model was applied to estimate the overall effects and the stratified effects of the MTHFR C677T polymorphism on the risk of DR, and study quality was also assessed. Results Strong associations were observed between the MTHFR C677T polymorphism and DR. The carries of MTHFR C677T were more likely to be found in the DR group in relative to the healthy control group with odds ratio 1.68, 2.55, and 2.31 respectively in allele contrast model (T vs. C, 95%CI: 1.29-2.18, P<0.001, I ²=78.4%), homozygous model (TT vs. CC, 95%CI: 1.70-3.83, P=0.008, I ²=54.4%) and dominant model (TT+CT vs. CC, 95%CI: 1.62-3.29, P<0.001, I ²=74.7%). This association can also be found in contrast to the Ncd (non-complicated diabetic mellitus) group (allele contrast, OR=1.50, 95%CI: 1.07-2.11, P=0.032, I ²=62.1%; homozygous, OR=2.39, 95%CI: 1.06-5.38, P=0.017, I ²=66.7%; dominant, OR=1.59, 95%CI: 0.97-2.62, P=0.056, I ²=56.5%). For the heterozygous model (CT vs. CC), the association was significant in contrast to the healthy control group (OR=1.46, 95%CI: 1.64-3.69, P=0, I ²=77.3%), while in contrast to the Ncd control group the association was not statistically meaningful (OR=1.38, 95%CI: 0.87-2.18, P=0.131, I ²=43.7%). For the recessive model, 1.92-fold increased risk was found only in contrast to the Ncd control group (95%CI: 1.07-3.43, P=0.064, I ²=55.0%). There was no significant association found in the models in contrast to the DM control group. Conclusion In this meta-analysis, we found an association between the MTHFR C677T polymorphism and DR, especially in contrast to the Ncd control group. Further studies are required to establish more definite relationship.
Alleles ; Diabetic Retinopathy/genetics* ; Female ; Gene Frequency ; Genetic Predisposition to Disease/genetics* ; Genotype ; Humans ; Male ; Methylenetetrahydrofolate Reductase (NADPH2)/genetics* ; Polymorphism, Single Nucleotide

Objective To investigate the association between total homocysteine (tHcy) level in plasma and methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C genetic polymorphisms in a Chinese Han nationality population with type 2 diabetes mellitus (T2DM) accompanied by dyslipidemia. Methods This case-control study enrolled T2DM patients with dyslipidemia and without dyslipidemia respectively. Sanger dideoxy-mediated chain-termination method was used to detect the gene polymorphisms of MTHFR C677T and A1298C. Plasma tHcy and lipid levels were measured as well. The genotype frequency and allele frequency between the dyslipidemia and non-dyslipidemia groups were compared by using Chi-square test. Plasma tHcy level of T2DM patients who carried the different genotypes was compared by Student's t test. Results Finally, 82 T2DM patients with dyslipidemia and 94 ones without dyslipidemia were included in this study. There was a significant correlation between tHcy level and MTHFR C677T gene polymorphism in T2DM patients (t=2.27, P=0.02). Moreover, the plasma tHcy level in the dyslipidemia patients who carried MTHFR 677 TT genotype was significantly higher than that in those with CT+CC genotype (13.62±6.97 vs. 10.95±3.62 μmol/L, t=2.20, P=0.03); while for patients without dyslipidemia, comparison of the tHcy level between those who carried the above two alleles showed no significantly difference (13.34±6.03 vs. 12.04±5.09 μmol/L, t=1.08, P=0.29). Conclusion MTHFR 677TT genotype might associate with higher tHcy level in T2DM patients with dyslipidemia.
Adult ; Aged ; Alleles ; Asian People/genetics* ; Base Sequence ; Case-Control Studies ; China ; Diabetes Mellitus, Type 2/genetics* ; Dyslipidemias/genetics* ; Gene Frequency ; Genotype ; Homocysteine/blood* ; Humans ; Linkage Disequilibrium ; Methylenetetrahydrofolate Reductase (NADPH2)/genetics* ; Middle Aged ; Polymorphism, Single Nucleotide

The isolated type of orofacial cleft, termed non-syndromic cleft lip with or without cleft palate (NSCL/P), is the second most common birth defect in China, with Asians having the highest incidence in the world. NSCL/P involves multiple genes and complex interactions between genetic and environmental factors, imposing difficulty for the genetic assessment of the unborn fetus carrying multiple NSCL/P-susceptible variants. Although genome-wide association studies (GWAS) have uncovered dozens of single nucleotide polymorphism (SNP) loci in different ethnic populations, the genetic diagnostic effectiveness of these SNPs requires further experimental validation in Chinese populations before a diagnostic panel or a predictive model covering multiple SNPs can be built. In this study, we collected blood samples from control and NSCL/P infants in Han and Uyghur Chinese populations to validate the diagnostic effectiveness of 43 candidate SNPs previously detected using GWAS. We then built predictive models with the validated SNPs using different machine learning algorithms and evaluated their prediction performance. Our results showed that logistic regression had the best performance for risk assessment according to the area under curve. Notably, defective variants in MTHFR and RBP4, two genes involved in folic acid and vitamin A biosynthesis, were found to have high contributions to NSCL/P incidence based on feature importance evaluation with logistic regression. This is consistent with the notion that folic acid and vitamin A are both essential nutritional supplements for pregnant women to reduce the risk of conceiving an NSCL/P baby. Moreover, we observed a lower predictive power in Uyghur than in Han cases, likely due to differences in genetic background between these two ethnic populations. Thus, our study highlights the urgency to generate the HapMap for Uyghur population and perform resequencing-based screening of Uyghur-specific NSCL/P markers.
Asian Continental Ancestry Group ; genetics ; China ; ethnology ; Cleft Lip ; genetics ; Cleft Palate ; genetics ; Genome-Wide Association Study ; Humans ; Infant ; Logistic Models ; Machine Learning ; Methylenetetrahydrofolate Reductase (NADPH2) ; genetics ; Polymorphism, Single Nucleotide ; Retinol-Binding Proteins, Plasma ; genetics ; Risk Assessment