Genetic polymorphisms modulate the folate metabolism of Brazilian individuals with Down syndrome

Individuals with Down syndrome (DS) carry three copies of the Cystathionine beta-synthase (C beta S) gene. The increase in the dosage of this gene results in an altered profile of metabolites involved in the folate pathway, including reduced homocysteine (Hcy), methionine, S-adenosylhomocysteine (SAH) and S-adenosylmethionine (SAM). Furthermore, previous studies in individuals with DS have shown that genetic variants in genes involved in the folate pathway influence the concentrations of this metabolism's products. The purpose of this study is to investigate whether polymorphisms in genes involved in folate metabolism affect the plasma concentrations of Hcy and methylmalonic acid (MMA) along with the concentration of serum folate in individuals with DS. Twelve genetic polymorphisms were investigated in 90 individuals with DS (median age 1.29 years, range 0.07-30.35 years; 49 male and 41 female). Genotyping for the polymorphisms was performed either by polymerase chain reaction (PCR) based techniques or by direct sequencing. Plasma concentrations of Hcy and MMA were measured by liquid chromatography-tandem mass spectrometry as previously described, and serum folate was quantified using a competitive immunoassay. Our results indicate that the MTHFR C677T, MTR A2756G, TC2 C776G and BHMT G742A polymorphisms along with MMA concentration are predictors of Hcy concentration. They also show that age and Hcy concentration are predictors of MMA concentration. These findings could help to understand how genetic variation impacts folate metabolism and what metabolic consequences these variants have in individuals with trisomy 21.

Evaluation of plasma homocysteine level according to the C677T and A1298C polymorphism of the enzyme MTHRF in type 2 diabetic adults

Objective: To determine plasma homocysteine levels during fasting and after methionine overload, and to correlate homocysteinemia according to methylenetetrahydrofolate reductase (MTHFR) polymorphism in type 2 diabetic adults. Subjects and methods: The study included 50 type 2 diabetic adults (DM group) and 52 healthy subjects (Control group). Anthropometric data, and information on food intake, serum levels of vitamin B 12, folic acid and plasma homocysteine were obtained. The identification of C677T and A1298C polymorphisms was carried out in the MTHFR gene. Results: There was no significant difference in homocysteinemia between the two groups, and hyperhomocysteinemia during fasting occurred in 40% of the diabetic patients and in 23% of the controls. For the same polymorphism, there was not any significant difference in homocysteine between the groups. In the Control group, homocysteinemia was greater in those subjects with C677T and A1298C polymorphisms. Among diabetic subjects, those with the A1298C polymorphism had lower levels of homocysteine compared with individuals with C677T polymorphism. Conclusion: The MTHFR polymorphism (C677T and A1298C) resulted in different outcomes regarding homocysteinemia among individuals of each group (diabetic and control). These data suggest that metabolic factors inherent to diabetes influence homocysteine metabolism. Arq Bras Endocrinol Metab. 2012;56(7):429-34

Association study between the rs165599 catechol-O-methyltransferase genetic polymorphism and schizophrenia in a Brazilian sample

Schizophrenia is a severe psychiatric disorder with frequent recurrent psychotic relapses and progressive functional impairment. It results from a poorly understood gene-environment interaction. The gene encoding catechol-O-methyltransferase (COMT) is a likely candidate for schizophrenia. Its rs165599 (A/G) polymorphism has been shown to be associated with alteration of COMT gene expression. Therefore, the present study aimed to investigate a possible association between schizophrenia and this polymorphism. The distribution of the alleles and genotypes of this polymorphism was investigated in a Brazilian sample of 245 patients and 834 controls. The genotypic frequencies were in Hardy-Weinberg equilibrium and no statistically significant differences were found between cases and controls when analyzed according to gender or schizophrenia subtypes. There was also no difference in homozygosis between cases and controls. Thus, in the sample studied, there was no evidence of any association between schizophrenia and rs165599 (A/G) polymorphism in the non-coding region 3' of the COMT gene.

Plasmatic higher levels of homocysteine in Non-alcoholic fatty liver disease (NAFLD)

Background Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease, which includes a spectrum of hepatic pathology such as simple steatosis, steatohepatitis, fibrosis and cirrhosis. The increased serum levels of homocysteine (Hcy) may be associated with hepatic fat accumulation. Genetic mutations in the folate route may only mildly impair Hcy metabolism. The aim of this study was to investigate the relation between liver steatosis with plasma homocysteine level and MTHFR C677T and A1298C polymorphisms in Brazilian patients with NAFLD. Methods Thirty-five patients diagnosed with NAFLD by liver biopsy and forty-five healthy controls neither age nor sex matched were genotyped for C677T and A1298C MTHFR polymorphisms using PCR-RFLP and PCR-ASA, respectively, and Hcy was determined by HPLC. All patients were negative for markers of Wilson’s, hemochromatosis and autoimmune diseases. Their daily alcohol intake was less than 100 g/week. A set of metabolic and serum lipid markers were also measured at the time of liver biopsies. Results The plasma Hcy level was higher in NAFLD patients compared to the control group (p = 0.0341). No statistical difference for genotypes 677C/T (p = 0.110) and 1298A/C (p = 0.343) in patients with NAFLD and control subjects was observed. The genotypes distribution was in Hardy-Weinberg equilibrium (677C/T p = 0.694 and 1298 A/C p = 0.188). The group of patients and controls showed a statistically significant difference (p < 0.001) for BMI and HOMA_IR, similarly to HDL cholesterol levels (p < 0,006), AST, ALT, γGT, AP and triglycerides levels (p < 0.001). A negative correlation was observed between levels of vitamin B12 and Hcy concentration (p = 0.005). Conclusion Our results indicate that plasma Hcy was higher in NAFLD than controls. The MTHFR C677T and A1298C polymorphisms did not differ significantly between groups, despite the 677TT homozygous frequency was higher in patients (17.14%) than in controls (677TT = 4.44%) (p > 0.05). The suggested genetic susceptibility to the MTHFR C677T and A1298C should be confirmed in large population based studies.

Expression of genes from the lignin synthesis pathway in guineagrass genotypes differing in cell-wall digestibility

Rapid decline in cell-wall digestibility hinders efficient use of warm-season grasses. The objective of this study was to identify genes whose expressions are related to the slope of decline in cell-wall digestibility. Eleven guineagrass genotypes were harvested at three ages and classified according to fibre digestibility. Extreme genotypes were separated into groups with either FAST or SLOW decline in fibre digestibility. Expression of transcripts from six genes from the lignin synthesis pathway was quantified by real-time PCR. Fast decline in fibre digestibility was associated with higher DM yield after 90 d of regrowth. Apart from lower fibre digestibility and higher lignin content for the FAST group, there were no other differences between the two groups for the chemical composition of stems and leaves. Maturity affected differently the expression of two of the six genes, cinnamate 4-hydroxylase and caffeoyl-CoA O-methyltransferase (C4H and CCoAOMT). Genotypes with fast decline in fibre digestibility had greater increase in the expression of C4H and CCoAOMT from 30 to 60 d of regrowth, than genotypes with slower decline. Expression of C4H and CCoAOMT appears to be related to the decline in cell-wall digestibility with advance in maturity of guineagrass.

COMT Met (158) modulates facial emotion recognition in bipolar I disorder mood episodes

Background: One of the many cognitive deficits reported in bipolar disorder (BD) patients is facial emotion recognition (FER), which has recently been associated with dopaminergic catabolism. Catechol-O-methyltransferase (COMT) is one of the main enzymes involved in the metabolic degradation of dopamine (DA) in the prefrontal cortex (PFC). The COMT gene polymorphism rs4680 (Val(158)Met) Met allele is associated with decreased activity of this enzyme in healthy controls. The objective of this study was to evaluate the influence of Val(158)Met on FER during manic and depressive episodes in BD patients and in healthy controls. Materials and methods: 64 BD type I patients (39 in manic and 25 in depressive episodes) and 75 healthy controls were genotyped for COMT rs4680 and assessed for FER using the Ekman 60 Faces (EK60) and Emotion Hexagon (Hx) tests. Results: Bipolar manic patients carrying the Met allele recognized fewer surprised faces, while depressed patients with the Met allele recognized fewer "angry" and "happy" faces. Healthy homozygous subjects with the Met allele had higher FER scores on the Hx total score, as well as on "disgust" and "angry" faces than other genotypes. Conclusion: This is the first study suggesting that COMT rs4680 modulates FER differently during BD episodes and in healthy controls. This provides evidence that PFC DA is part of the neurobiological mechanisms of social cognition. Further studies on other COMT polymorphisms that include euthymic BD patients are warranted. ClinicalTrials.gov Identifier: NCT00969. (C) 2011 Elsevier B.V. All rights reserved.

Polymorphism C1420T of Serine hydroxymethyltransferase gene on maternal risk for Down syndrome

Recent researches have investigated the factors that determine the maternal risk for Down syndrome (DS) in young woman. In this context, some studies have demonstrated the association between polymorphisms in genes involved on folate metabolism and the maternal risk for DS. These polymorphisms may result in abnormal folate metabolism and methyl deficiency, which is associated with aberrant chromosome segregation leading to trisomy 21. In this study, we analyzed the influence of the polymorphism C1420T in Serine hydroxymethyltransferase (SHMT) gene on maternal risk for DS and on metabolites concentrations of the folate pathway (serum folate and plasma homocysteine and methylmalonic acid). The study group was composed by 105 mothers with DS children (case group) and 185 mothers who had no children with DS (control group). The genotype distribution did not show significant statistical difference between case and control mothers (P = 0.24) however a protective effect between genotypes CC (P = 0.0002) and CT (P < 0.0001) and maternal risk for DS was observed. Furthermore, the SHMT C1420T polymorphism (rs1979277) does not affect the concentration of metabolites of folate pathway in our DS mothers. In conclusion, our data showed a protective role for the genotypes SHMT CC and CT on maternal risk for DS. The concentrations of metabolites of folate pathway did not differ significantly between the genotypes SHMT.

The Diversity of Polyketide Synthase Genes from Sugarcane-Derived Fungi

The chemical ecology and biotechnological potential of metabolites from endophytic and rhizosphere fungi are receiving much attention. A collection of 17 sugarcane-derived fungi were identified and assessed by PCR for the presence of polyketide synthase (PKS) genes. The fungi were all various genera of ascomycetes, the genomes of which encoded 36 putative PKS sequences, 26 shared sequence homology with beta-ketoacyl synthase domains, while 10 sequences showed homology to known fungal C-methyltransferase domains. A neighbour-joining phylogenetic analysis of the translated sequences could group the domains into previously established chemistry-based clades that represented non-reducing, partially reducing and highly reducing fungal PKSs. We observed that, in many cases, the membership of each clade also reflected the taxonomy of the fungal isolates. The functional assignment of the domains was further confirmed by in silico secondary and tertiary protein structure predictions. This genome mining study reveals, for the first time, the genetic potential of specific taxonomic groups of sugarcane-derived fungi to produce specific types of polyketides. Future work will focus on isolating these compounds with a view to understanding their chemical ecology and likely biotechnological potential.

Analysis of MLL2 gene in the first Brazilian family with Kabuki syndrome

Most patients with Kabuki syndrome (KS) are the only person in their family with the condition. However, familial cases of KS have been described showing evidence that this syndrome can be inherited as a dominant trait with variable expressivity. We report on two related individuals with facial findings characteristic of KS. The proposita had arched eyebrows, long and upward slanting palpebral fissures, cleft lip and palate, retromicrognathia, brachydactyly of hands and feet, stubby fingers, nail hypoplasia, and prominent finger pads. Her mother had eyebrows with dispersed lateral half, long and upward slanting palpebral fissures, retrognathia, abnormal and posteriorly rotated ears, prominent finger pads, brachydactyly of feet, learning difficulties, and psychomotor development delay. DNA sequencing revealed a novel missense mutation in the MLL2 gene in both the proposita and her mother. The mutation (p.R5432Q) was found in the exon 51, within the SET domain of the gene, which confers methyltransferase activity on the protein. Therefore, the epigenetic and transcriptional regulatory properties of this protein may be altered and this suggests that the mutation is the cause of phenotype observed in both the patient and her mother. The clinical signs and the molecular evidence in this family further support the notion that KS is an autosomal dominant condition with variable expressivity. To our knowledge this is the first report of a Brazilian family with recurrence of this syndrome. (C) 2012 Wiley Periodicals, Inc.

Methionine-induced hyperhomocysteinemia reverts fibrinolytic pathway activation in a murine model of acute promyelocytic leukemia

Increased fibrinolysis is an important component of acute promyelocytic leukemia (APL) bleeding diathesis. APL blasts overexpress annexin II (ANXII), a receptor for tissue plasminogen activator (tPA), and plasminogen, thereby increasing plasmin generation. Previous studies suggested that ANXII plays a pivotal role in APL coagulopathy. ANXII binding to tPA can be inhibited by homocysteine and hyperhomocysteinemia can be induced by L-methionine supplementation. In the present study, we used an APL mouse model to study ANXII function and the effects of hyperhomocysteinemia in vivo. Leukemic cells expressed higher ANXII and tPA plasma levels (11.95 ng/mL in leukemic vs 10.74 ng/mL in wild-type; P = .004). In leukemic mice, administration of L-methionine significantly increased homocysteine levels (49.0 mu mol/mL and < 6.0 mu mol/mL in the treated and nontreated groups, respectively) and reduced tPA levels to baseline concentrations. The latter were also decreased after infusion of the LCKLSL peptide, a competitor for the ANXII tPA-binding site (11.07 ng/mL; P = .001). We also expressed and purified the p36 component of ANXII in Pichia methanolica. The infusion of p36 in wild-type mice increased tPA and thrombin-antithrombin levels, and the latter was reversed by L-methionine administration. The results of the present study demonstrate the relevance of ANXII in vivo and suggest that methionine-induced hyperhomocysteinemia may reverse hyperfibrinolysis in APL. (Blood. 2012;120(1):207-213)

Proteomic analysis of banana fruit reveals proteins that are differentially accumulated during ripening

Bananas (Musa spp.) are highly perishable fruit of notable economic and nutritional relevance. Because the identification of proteins involved in metabolic pathways could help to extend green-life and improve the quality of the fruit, this study aimed to compare the proteins of banana pulp at the pre-climacteric and climacteric stages. The use of two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) revealed 50 differentially expressed proteins, and comparing those proteins to the Mass Spectrometry Protein Sequence Database (MSDB) identified 26 known proteins. Chitinases were the most abundant types of proteins in unripe bananas, and two isoforms in the ripe fruit have been implicated in the stress/defense response. In this regard, three heat shock proteins and isoflavone reductase were also abundant at the climacteric stage. Concerning fruit quality, pectate lyase, malate dehydrogenase, and starch phosphorylase accumulated during ripening. In addition to the ethylene formation enzyme amino cyclo carboxylic acid oxidase, the accumulation of S-adenosyl-L-homocysteine hydrolase was needed because of the increased ethylene synthesis and DNA methylation that occurred in ripening bananas. Differential analysis provided information on the ripening-associated changes that occurred in proteins involved in banana flavor, texture, defense, synthesis of ethylene, regulation of expression, and protein folding, and this analysis validated previous data on the transcripts during ripening. In this regard, the differential proteomics of fruit pulp enlarged our understanding of the process of banana ripening. (C) 2012 Elsevier B.V. All rights reserved.

Ciprofloxacin has antifibrotic effects in scleroderma fibroblasts via downregulation of Dnmt1 and upregulation of Fli1

Systemic sclerosis (SSc) is characterized by fibrosis of the skin and internal organs. The present study was undertaken to examine the effects of ciprofloxacin, a fluoroquinolone antibiotic implicated in matrix remodeling, on dermal and lung fibroblasts obtained from SSc patients. Dermal and lung fibroblasts from SSc patients and healthy subjects were treated with ciprofloxacin. Western blotting was used to analyze protein levels and RT-PCR was used to measure in RNA expression. The pharmacologic inhibitor UO126 was used to block Erk1/2 signaling. SSc dermal fibroblasts demonstrated a significant decrease in collagen type I mRNA and protein levels after antibiotic treatment, while healthy dermal fibroblasts were less sensitive to ciprofloxacin, downregulating collagen only at the protein levels. Connective tissue growth factor (CCN2) gene expression was significantly reduced and matrix metalloproteinase (MMPI) levels were enhanced after ciprofloxacin treatment to a similar extent in healthy and SSc fibroblasts. Ciprofloxacin induced Erk1/2 phosphorylation, and Erk1/2 blockade completely prevented MMP1 upregulation. However. Smad1 and Smad3 activation in response to TGF beta was not affected. The expression of friend leukemia integration factor 1 (Fli1). a transcriptional repressor of collagen, was increased after treatment with ciprofloxacin only in SSc fibroblasts, and this was accompanied by a decrease in the levels of DNA methyltransferase 1 (Dnmt1). Similar effects were observed in SSc-interstitial lung disease (ILD) lung fibroblasts. In summary, our study demonstrates that ciprofloxacin has antifibrotic actions in SSc dermal and lung fibroblasts via the downregulation of Dnmt1, the upregulation of Fli1 and induction of MMPI gene expression via an Erk1/2-dependent mechanism. Thus, our data suggest that ciprofloxacin may he an attractive therapy for SSc skin and lung fibrosis.

Molecular phylogeny and phenotypic variability of clinical and environmental strains of Aspergillus flavus

Aspergillus flavus is the second most common cause of aspergillosis infection in immunocompromised patients and is responsible for the production of aflatoxins. Little is known about the population structure of A. flavus, although recent molecular and phenotypic data seem to demonstrate that different genetic lineages exist within this species. The aim of this study was to carry out a morphological, physiological, and molecular analysis of a set of clinical and environmental isolates to determine whether this variability is due to species divergence or intraspecific diversity, and to assess whether the clinical isolates form a separate group. The amdS and omtA genes were more phylogenetically informative than the other tested genes and their combined analysis inferred three main clades, with no clear distinction between clinical and environmental isolates. No important morphological and physiological differences were found between the members of the different clades, with the exception of the assimilation of D-glucosamine, which differentiates the members of the clade II from the others. (C) 2012 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

Brazilian nut consumption improves selenium status and glutathione peroxidase activity and reduces atherogenic risk in obese women

Studies have shown that there are inverse relationships between nut consumption and the reduction of cardiovascular risk. This study tested the hypothesis that daily consumption of Brazilian nuts would have a positive effect upon selenium (Se) status, erythrocyte glutathione peroxidase activity, lipid profile, and atherogenic risk in severely obese women. Thirty-seven severely obese women each consumed 1 Brazilian nut a day (290 mu g of Se a day) for 8 weeks. Blood Se concentrations, total erythrocyte glutathione peroxidase activity, lipid profile, and Castelli I and H indexes were evaluated before and after the nuts consumption. All the patients were Se deficient at baseline; this deficiency was remedied by the consumption of the Brazilian nut (P < .0001). The intake of Brazilian nuts promoted a significant increase in high-density lipoprotein cholesterol concentrations (P < .00001), which then resulted in a significant improvement of the Castelli I (P < .0002) and II (P < .0004) indexes. This study shows that obese people who implement daily consumption of Brazilian nuts can improve both Se status and lipid profile, especially high-density lipoprotein cholesterol levels, thereby reducing cardiovascular risks. (C) 2012 Published by Elsevier Inc.

Genome analysis of DNA repair genes in the alpha proteobacterium Caulobacter crescentus

Abstract Background The integrity of DNA molecules is fundamental for maintaining life. The DNA repair proteins protect organisms against genetic damage, by removal of DNA lesions or helping to tolerate them. DNA repair genes are best known from the gamma-proteobacterium Escherichia coli, which is the most understood bacterial model. However, genome sequencing raises questions regarding uniformity and ubiquity of these DNA repair genes and pathways, reinforcing the need for identifying genes and proteins, which may respond to DNA damage in other bacteria. Results In this study, we employed a bioinformatic approach, to analyse and describe the open reading frames potentially related to DNA repair from the genome of the alpha-proteobacterium Caulobacter crescentus. This was performed by comparison with known DNA repair related genes found in public databases. As expected, although C. crescentus and E. coli bacteria belong to separate phylogenetic groups, many of their DNA repair genes are very similar. However, some important DNA repair genes are absent in the C. crescentus genome and other interesting functionally related gene duplications are present, which do not occur in E. coli. These include DNA ligases, exonuclease III (xthA), endonuclease III (nth), O6-methylguanine-DNA methyltransferase (ada gene), photolyase-like genes, and uracil-DNA-glycosylases. On the other hand, the genes imuA and imuB, which are involved in DNA damage induced mutagenesis, have recently been described in C. crescentus, but are absent in E. coli. Particularly interesting are the potential atypical phylogeny of one of the photolyase genes in alpha-proteobacteria, indicating an origin by horizontal transfer, and the duplication of the Ada orthologs, which have diverse structural configurations, including one that is still unique for C. crescentus. Conclusion The absence and the presence of certain genes are discussed and predictions are made considering the particular aspects of the C. crescentus among other known DNA repair pathways. The observed differences enlarge what is known for DNA repair in the Bacterial world, and provide a useful framework for further experimental studies in this organism.