Discovery of methoxyacetylcarbamide in the urine of normal adults and phenylketonuric children

In order to study metabolic distinctions in phenylketonuria, urinary metabolites in the form of trimethylsilyl derivatives have been characterized by high resolution gas chromatography and mass spectrometry. A previously unknown metabolite has been found in the urine of some untreated phenylketonuric infants between 2 and 5 yr of age. The metabolite was absent in healthy children of the same age. The metabolite appeared to be present in the urine of apparently healthy adults (25-32 yr old). The metabolite was identified as methoxyacetylcarbamide on the basis of mass fragmentation analysis and compared with synthetic methoxyacetylcarbamide. Their retention times and mass spectra coincided.     

Indications of changed amino acid homeostasis in untreated and treated PKU

Amino acid patterns were investigated in children with untreated and treated phenylketonuria (PKU) and compared with hospitalized paediatric control group. Correlation ratios, i.e. the ratio between the number of statistically significant correlations between pairs of amino acids, were calculated and found to be 0.125, 0.331 and 0.35 in the three groups. Link ratios, i.e. the frequency of statistically significant correlations between particular amino acid and other amino acids, varied between 0.00 and 0.18, 0.06 and 0.56, and 0.18 and 0.59 in the same groups. Link ratios for especially isoleucine, histidine and arginine were decreased in treated PKU compared to the control group. A reverse non-linear relationship was established between decreased plasma phenylalanine induced by dietary treatment and increased threonine in plasma. These findings indicate that amino acid homostasis is disturbed in untreated PKU and not fully normalized in treated patients. The clinical relevance of the findings is unknown.     

Excretion of phenylpyruvic, 4-hydroxyphenylpyruvic and indolyl-3-acetic acids by the skin fibroblasts from a phenylketonuric child

Summary High-resolution gas chromatography and mass spectrometry have been used to analyse the changing chemical composition of the culture medium upon the growth of skin fibroblasts from a healthy individual and from a classical phenylketonuric (PKU) patient. The PKU fibroblasts, unlike normal ones, were found to excrete into the culture medium phenylpyruvate, 4-hydroxyphenylpyruvate, indolyl-3-acetate and an unidentified metabolite containing the phenyl group. This testifies to the disturbed metabolism of phenylalanine, tyrosine and tryptophan in the PKU fibroblasts. This seems to be the reason for their reduced viability as compared with normal fibroblasts.     

Content of phenylalanine,tyrosine and their metabolites in CSF in phenylketonuria

Summary By using ion-exchange chromatography and gas chromatography coupled with mass spectrometry, the content of phenylalanine, tyrosine and their metabolites typical of phenylketonuria (PKU) was determined in the cerebrospinal fluid (CSF) of 8 untreated children with classical PKU and 9 controls. At the same time, plasma and urine were analysed. In PKU the content of phenylalanine is increased on average 23 times in plasma and CSF. The content of phenylalanine and tyrosine in CSF is about 4 times less as compared with plasma. The phenylalanine-to-tyrosine ratio is approximately the same for these fluids both in control and in PKU. This indicates that the transport of phenylalanine and tyrosine through the blood-brain barrier is not disturbed in PKU.Phenylpyruvate and 4-hydroxyphenylpyruvate are either not detected or present in very low concentrations in the CSF of children with PKU; their derivatives, phenyllactate and 4-hydroxyphenyllactate, are present in relatively higher concentrations. This indicates increased metabolic conversion in brain tissues.     

Scaffolding a Caenorhabditis nematode genome with RNA-seq

Efficient sequencing of animal and plant genomes by next-generation technology should allow many neglected organisms of biological and medical importance to be better understood. As a test case, we have assembled a draft genome of Caenorhabditis sp. 3 PS1010 through a combination of direct sequencing and scaffolding with RNA-seq. We first sequenced genomic DNA and mixed-stage cDNA using paired 75-nt reads from an Illumina GAII. A set of 230 million genomic reads yielded an 80-Mb assembly, with a supercontig N50 of 5.0 kb, covering 90% of 429 kb from previously published genomic contigs. Mixed-stage poly(A)(+) cDNA gave 47.3 million mappable 75-mers (including 5.1 million spliced reads), which separately assembled into 17.8 Mb of cDNA, with an N50 of 1.06 kb. By further scaffolding our genomic supercontigs with cDNA, we increased their N50 to 9.4 kb, nearly double the average gene size in C. elegans. We predicted 22,851 protein-coding genes, and detected expression in 78% of them. Multigenome alignment and data filtering identified 2672 DNA elements conserved between PS1010 and C. elegans that are likely to encode regulatory sequences or previously unknown ncRNAs. Genomic and cDNA sequencing followed by joint assembly is a rapid and useful strategy for biological analysis.     

ON INTRACELLULAR FORMATION OF ETHANOL AND ITS POSSIBLE ROLE IN ENERGY METABOLISM

Despite a great number of papers devoted to studies of the influenceof alcohol on man's health, very few of them discuss the issueof the presence of ethanol in the human body not connected withalcohol consumption. Such ethanol is commonly called endogenous.It is believed to originate from the microbial fermentationof the carbohydrates in the gastro-intestinal tract (Krebs andPerkins, . . . [Full Text of this Article]REFERENCES     

Analysis of effects of the herbal preparation Circulat on gene expression levels in cultured human fibroblasts

Circulat is a systemic standardized plant extract formulation that was developed for the prevention of severe manifestations of type 2 diabetes such as necrotic damage of the plantar foot. With the aim of revealing the molecular mechanisms underlying Circulat's biological activity, the effects of Circulat treatment on gene expression levels were examined in the cultured human fibroblast cell line MRC-5 using Affymetrix oligonucleotide microarrays. The analysis identified 187 genes, the expression levels of which underwent significant changes upon Circulat treatment. These include four genes (IL6, HMGA1, SLC19A2 and C4A) that have been implicated previously in the development of diabetes. A large proportion of the identified genes are involved in energy metabolism, protein synthesis, glucose metabolism and signaling pathways. Synergistic action of the Circulat components has also been revealed. Prospective applications of microarray analysis in phytopharmacology are discussed.