To utilize Pichia pastoris to produce S-adenosyl-L-methionine (SAM), an intracellular expression vector harboring S. cerevisiae SAM2 was transformed into GS115. A recombinant strain having 2 copies of expression cassette was obtained through G418 resistance screening. This strain had higher SAM synthetase activity and higher SAM production capacity than the original strain, when cultured in medium containing methanol and methionine. The carbon source and nitrogen source of medium was optimized. The results showed SAM production by this strain was closely related to carbon metabolism. With supplementation of 0.2% glycerol every day from the beginning of 3rd day, this strain produced 1.58 g/L SAM when cultured in a medium containing 0.75% L-methionine and optimized carbon and nitrogen source after 6 days.
Methionine Adenosyltransferase ; genetics ; metabolism ; Pichia ; genetics ; Recombinant Proteins ; metabolism ; S-Adenosylmethionine ; biosynthesis

The yield of S-adenosyl-L-methionine (SAM) on high-cell-density fermentation by saccharomyces cerevisiae is mostly affected by the feeding strategy of pre-L-methionine. The mutant strain SAM0801 that could accumulate more SAM was used in this study. Six high-cell-density fermentation experiments in 5 L fermentor were investigated to get the optimal feeding time and amount of L-methionine. The results showed that when 40 g L-methionine was added in the fermentor after 30 h fermentation, a dry cell weight of 100 g/L was achieved. Under this condition, after 58 h fermentation, both the dry cell weight and the yield of SAM reached the maximum, 168 g/L and 14.48 g/L respectively.
Bioreactors ; microbiology ; Fermentation ; Methionine ; analysis ; metabolism ; Mutation ; S-Adenosylmethionine ; biosynthesis ; Saccharomyces cerevisiae ; genetics ; growth & development ; metabolism

OBJECTIVE: To explore the clinical features and genetic basis of a child with Galactosemia. METHODS: A child who had presented at the Children's Hospital Affiliated to Zhengzhou University on November 20, 2019 was selected as the study subject. Clinical data of the child was collected. Whole exome sequencing was carried out for the child. Candidate variants were validated by Sanger sequencing. RESULTS: Clinical manifestations of the child have included anemia, feeding difficulty, jaundice, hypomyotonia, abnormal liver function and coagulation abnormality. Tandem mass spectrometry showed increased citrulline, methionine, ornithine and tyrosine. Urine organic acid analysis showed increased phenyllactic acid, 4-hydroxyphenylacetic acid, 4-hydroxyphenyllactic acid, 4-hydroxyphenylpyruvate and N-acetyltyrosine. Genetic testing revealed that the child has harbored compound heterozygous variants of the GALT gene, namely c.627T>A (p.Y209*) and c.370G>C (p.G124R), which were respectively inherited from her healthy parents. Among these, c.627T>A (p.Y209*) was known as a likely pathogenic variant, while c.370G>C (p. G124R) was unreported previously and also predicted as a likely pathogenic variant(PM1+PM2_Supporting+PP3_Moderate+PPR). CONCLUSION Above discovery has expanded the spectrum of the GALT gene variants underlying Galactosemia. Patients with thrombocytopenia, feeding difficulties, jaundice, abnormal liver function and coagulation abnormality without obvious causes should be analyzed by screening of metabolic diseases in combination with genetic testing.
Child ; Female ; Humans ; Galactosemias/genetics* ; Genetic Testing ; Health Status ; Methionine ; Muscle Hypotonia ; Mutation

Circadian Clocks/genetics* ; Reactive Oxygen Species ; Methionine ; Gastrointestinal Microbiome ; Gastrointestinal Tract ; Racemethionine ; Gene Expression

OBJECTIVE: To summarize newborn screening for methionine adenosyltransferase I/III (MAT I/III) deficiency in Quanzhou region of Fujian Province. METHODS: A total of 364 545 neonates were screened for inherited metabolic diseases by tandem mass spectrometry. High-throughput next generation sequencing combined with Sanger sequencing was used to detect potential variants in newborns with MAT I/III deficiency. Pathogenicity of suspected variants was predicted by using MutationTaster and HSF software. RESULTS: Three newborns were identified with MAT I/III deficiency by newborn screening, which yielded an incidence rate of 1 in 121 515. Amino acid and acylcarnitine analysis suggested that the serum methionine of the three patients have increased to various extents. All patients showed normal growth and development during follow-up, and were found to carry MAT1A gene variants including two missense variants [c.776C>T (p.Ala259Val) and c.791G>A (p.Arg264His)] and a synonymous variant [c.360C>T (p.Cys120Cys)]. Among these, c.776C>T (p.Ala259Val) and c.791G>A (p.Arg264His) were known to be pathogenic, whereas c.360C>T (p.Cys120Cys) was a novel variant. Bioinformatics analysis suggested that this variant may alter RNA splicing and affect the structure and function of the MAT1A protein. CONCLUSION A systematic review of newborn screening for MAT I/III deficiency was provided. Discovery of the novel variant has enriched the variant profile of the MAT1A gene and provided a basis for the diagnosis of this disease.
Amino Acid Metabolism, Inborn Errors ; diagnosis ; China ; Genetic Variation ; Humans ; Infant, Newborn ; Methionine Adenosyltransferase ; deficiency ; genetics ; Neonatal Screening

OBJECTIVE: To explore the role of the microbiota in drug naïve first-onset schizophrenia patients and to seek evidence from multidimensional longitudinal analyses of the intestinal microbiome and clinical phenotype with antipsychotic drugs (APDs) therapy. METHODS: In this study, 28 drug naïve first onset schizophrenia patients and age-, gender- and education-matched 29 healthy controls were included, and the patients were treated with APDs. We collected fecal and serum samples at baseline and after 6 weeks of treatment to identify the different microbiota strains and analyse their correlation with clinical symptoms and serum metabolites. The 16S rRNA genes of the gut microbiota were sequenced, and the diversity and relative abundance at the phylum and genus levels were analyzsed in detail. The PANSS score, BMI changed value, and serum metabolome were included in the data analyses. RESULTS: A multiomics study found a potential connection among the clinical phenotype, microbiota and metabolome. The species diversity analyses revealed that the alpha diversity index (chao1, ACE, and goods_coverage) in the schizophrenia APDs group was significantly lower than that in the control group, and the schizophrenia group had clear demarcation from the control group. The microbiota composition analysis results showed that the relative abundance of the genera of Bacteroides, Streptococcus, Romboutsia, and Eubacterium ruminantium group significantly changed after APDs treatment in the schizophrenia patients. These strains could reflect the APDs treatment effect. More genera had differences between the patient and control groups. The LEfSe analysis showed that Prevotella_9 and Bacteroides were enriched in schizophrenia, while Blautia, Dialister, and Roseburia were enriched in the control group. The correlation analysis between microbiota and clinical symptoms showed that Bifidobacterium in schizophrenia was positively correlated with the PANSS reduction rate of the general psychopathology scale. The BMI changed value was positively correlated with the alteration of Clostridium_sensu_stricto_1 during treatment and the baseline abundance of Bacteroides. Moreover, metabolomic data analysis revealed a significant correlation between specific genera and metabolites, such as L-methionine, L-proline, homovanillic acid, N-acetylserotonin, and vitamin B6. CONCLUSION Our study found some microbiota features in schizophrenia patients and healthy controls, and several strains were correlated with APDs effects. Furthermore, the multiomics analysis implies the intermediate role of microbiota between antipsychotic effects and serum metabolites and provides new evidence to interpret the difference from multiple levels in the pathogenesis and pharmacological mechanism of schizophrenia.
Humans ; Antipsychotic Agents ; Homovanillic Acid ; Metabolomics/methods* ; Methionine ; Microbiota ; Proline ; RNA, Ribosomal, 16S/genetics* ; Schizophrenia ; Vitamin B 6 ; Feces

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

OBJECTIVETo investigate the association of the polymorphisms of methionine metabolism genes and the phenotype of X-linked adrenoleukodystrophy (X-ALD) and clinical severity.

METHODSThe clinical information of 120 X-ALD patients were analyzed and three genetic variants involved in the methionine metabolism, including cystathionine beta-synthase (CBS) c.844_855ins68, 5-methyltetrahydrofolate-homocysteine-S-methyltransferase (MTR) c.2756A to G, and transcobalamin 2 (TC2) c.776 C to G were analyzed by polymerase chain reaction and sequencing. The association between these polymorphisms and phenotype of X-ALD was studied.

RESULTSThe frequency of GG genotype of the TC2 c.776 C/G was higher in patients with central nervous system(CNS) demyelination than in controls (P= 0.012). However, the other two polymorphisms did not show any significant associations with the phenotypes.

CONCLUSIONThe GG genotype of TC2 c.776 C/G may contribute to X-ALD phenotype.

5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase ; genetics ; Adrenoleukodystrophy ; genetics ; Cystathionine beta-Synthase ; genetics ; Gene Frequency ; Genotype ; Humans ; Male ; Methionine ; metabolism ; Phenotype ; Polymorphism, Genetic ; Transcobalamins ; genetics

This case study reports a rare fibrinogen variant, gamma Met310Thr mutation, for the first time in Korea. The case shows a point mutation from T to C in the 1,007th nucleotide of the FGG gene. This report describes a variant fibrinogen, hereinafter called "fibrinogen Yecheon", using the name after the town where the patient was living at the time of diagnosis. Fibrinogen Yecheon has a de novo heterozygous point mutation of FGG resulting in gamma Met310Thr and subsequent extra N-glycosylation at gamma Asn308. Extra N-glycosylated fibrinogen is considered a main inhibitor of normal fibrinogen activity.
Base Sequence ; *Blood Coagulation Disorders, Inherited/genetics/physiopathology ; DNA Mutational Analysis ; Fibrinogens, Abnormal/*genetics ; Humans ; Korea ; Male ; Methionine/*genetics ; Molecular Sequence Data ; *Point Mutation ; Threonine/*genetics ; Young Adult

OBJECTIVE: To investigate the relationship between serum brain-derived neurotrophic factor, concentrations and BDNF gene Val66Met polymorphism and amnestic mild cognitive impairment (aMCI), and neuropsychological characteristics. METHODS: Ninety-nine aMCI patients and 99 matched normal controls were recruited for the study. Multi-dimension neuropsychologic tests were used to extensively assess the cognitive function, an enzyme-linked immunosorbent assay was applied to measure serum BDNF concentrations, and polymerase chain reaction-restriction fragment length polymorphism was used to analyse BDNF gene Val66Met polymorphism in the subjects. RESULTS: The scores of neuropsychologic tests in aMCI patients were significantly lower than those in the normal controls (all P<0.001), with the largest impairment on delayed recall of the auditory verbal memory test (AVMT) which reflect verbal episodic memory. The serum concentrations of BDNF in aMCI patients (median: 4.37 microg/L) were significantly lower than those of the normal controls (median: 4.98 microg/L) (z=-2.449, P=0.014). There was positive correlation between the serum concentrations of BDNF and the scores on delayed recall of AVMT (r=0.264, P=0.008). No significant differences were found for the genotype and allele distribution of BDNF Val66Met polymorphism between aMCI patients and the normal controls. BDNF Val66Met polymorphism was not associated with serum BDNF concentrations and cognitive assessment scores in aMCI patients (P>0.05). CONCLUSION aMCI is characterized by episodic memory impairment. Decreased BDNF concentrations may play a role in the pathophysiology of aMCI, and BDNF gene Val66Met polymorphism may not be an important genetic factor in susceptibility to aMCI.
Aged ; Aged, 80 and over ; Alzheimer Disease ; genetics ; Amnesia ; blood ; genetics ; Brain-Derived Neurotrophic Factor ; blood ; genetics ; Cognition Disorders ; blood ; genetics ; Female ; Humans ; Male ; Methionine ; genetics ; Polymorphism, Genetic ; genetics ; Valine ; genetics