Nucleolar Essential Protein 1 (Nep1): Elucidation of enzymatic catalysis mechanism by molecular dynamics simulation and quantum mechanics study.

The Nep1 protein is essential for the formation of eukaryotic and archaeal small ribosomal subunits, and it catalyzes the site-directed SAM-dependent methylation of pseudouridine (Ψ) during pre-rRNA processing. It possesses a non-trivial topology, namely, a 3 knot in the active site. Here, we address the issue of seemingly unfeasible deprotonation of Ψ in Nep1 active site by a distant aspartate residue (D101 in S.

Genetic Attenuation of Paraoxonase 1 Activity Induces Proatherogenic Changes in Plasma Proteomes of Mice and Humans.

High-density lipoprotein (HDL), in addition to promoting reverse cholesterol transport, possesses anti-inflammatory, antioxidative, and antithrombotic activities. Paraoxonase 1 (PON1), carried on HDL in the blood, can contribute to these antiatherogenic activities. The - polymorphism involves a change from glutamine (Q variant) to arginine (R variant) at position 192 of the PON1 protein and affects its enzymatic activity.

Cystathionine β-synthase deficiency: different changes in proteomes of thrombosis-resistant Cbs mice and thrombosis-prone CBS humans.

Cystathionine β-synthase (CBS)-deficient patients are prone to vascular thrombosis. In contrast, Cbs mice show no abnormalities in blood coagulation. To identify molecular basis underlying these disparately different thrombotic phenotypes, we analyzed plasma proteomes of Cbs vs.

Serum Proteome Alterations in Human Cystathionine β-Synthase Deficiency and Ischemic Stroke Subtypes.

Ischemic stroke induces brain injury via thrombotic or embolic mechanisms involving large or small vessels. Cystathionine β-synthase deficiency (CBS), an inborn error of metabolism, is associated with vascular thromboembolism, the major cause of morbidity and mortality in affected patients. Because thromboembolism involves the brain vasculature in these patients, we hypothesize that CBS deficiency and ischemic stroke have similar molecular phenotypes.

The protective effect of niacinamide on CHO AA8 cell line against ultraviolet radiation in the context of main cytoskeletal proteins.

Background: Niacinamide is a stable and water-soluble form of vitamin B3, a valuable and versatile cosmetic ingredient, which is well absorbed and tolerated by the skin. A large body of literature has reported on the antioxidant and cell repair properties of niacinamide. Therefore, it has been shown to be useful in the protection of the skin against ultraviolet B (UVB) radiation and free radicals.

Assessment of intake and nutritional status of vitamin b1, b2, and b6 in men and women with different physical activity levels.

The purpose of the present study was to examine the nutritional status of vitamin B1, B2, and B6 in respect to dietary intake of these vitamins and activity coefficients of the erythrocyte enzymes transketolase, glutathione reductase, and aspartic aminotransferase in young men and women with different physical activity levels. The participants of this study were 20 women and 20 men with high physical activity (groups HAW and HAM, respectively), and 20 women and 20 men with low physical activity (groups LAW and LAM, respectively). The intake of vitamins B1, B2, B6, proteins, and calorie content of the diet was based on the average of the 4-day dietary recalls.

The level of sulfane sulfur in the fungus Aspergillus nidulans wild type and mutant strains.

The interdependence of the sulfane sulfur metabolism and sulfur amino acid metabolism was studied in the fungus Aspergillus nidulans wild type strain and in mutants impaired in genes encoding enzymes involved in the synthesis of cysteine (a precursor of sulfane sulfur) or in regulatory genes of the sulfur metabolite repression system. It was found that a low concentration of cellular cysteine leads to elevation of two sulfane sulfurtransferases, rhodanase and cystathionine gamma-lyase, while the level of 3-mercaptopyruvate sulfurtransferase remains largely unaffected. In spite of drastic differences in the levels of biosynthetic enzymes and of sulfur amino acids due to mutations or sulfur supplementation of cultures, the level of total sulfane sulfur is fairly stable.

A novel mutation in the glucose-6-phosphate dehydrogenase gene in a subject with chronic nonspherocytic hemolytic anemia--characterization of enzyme using yeast expression system and molecular modeling.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human enzymopathy. Human G6PD gene is highly polymorphic, with over 130 mutations identified, many of which cause hemolytic anemia. We studied a novel point mutation in the G6PD gene 1226 C-->G, predicting the proline 409 to arginine substitution (G6PD Suwalki).

Transcriptional regulation of methionine synthase by homocysteine and choline in Aspergillus nidulans.

Roles played by homocysteine and choline in the regulation of MS (methionine synthase) have been examined in fungi. The Aspergillus nidulans metH gene encoding MS was cloned and characterized. Its transcription was not regulated by methionine, but was enhanced by homocysteine and repressed by choline and betaine.

Compound heterozygosity of two missense mutations in the NADH-cytochrome b5 reductase gene of a Polish patient with type I recessive congenital methaemoglobinaemia.

A case of type I methaemoglobinaemia observed in a Polish subject with compound heterozygosity for two mutations in the reduced nicotinamide adenine dinucleotide (NADH) cytochrome b5 reductase (b5R) gene is described. One is a novel mutation 647T-->C which leads to substitution of isoleucine by threonine at position 215 (I215T). This maternal mutation was found in several family members.

Several mutations including two novel mutations of the glucose-6-phosphate dehydrogenase gene in Polish G6PD deficient subjects with chronic nonspherocytic hemolytic anemia, acute hemolytic anemia, and favism.

DNA sequencing revealed seven different glucose-6-phosphate dehydrogenase (G6PD) mutations in G6PD deficient subjects from 10 Polish families. Among them we found two novel mutations: 679C-->T (G6PD Radlowo, class 2) and a 1006A-->G (G6PD Torun, class 1). Variant G6PD Radlowo was characterized biochemically.

Identification of new regulatory genes controlling synthesis of folate-dependent enzymes in Aspergillus nidulans.

Prototrophic revertants of a meth2 strain of aspergillus nidulans which is impaired in the regulation of synthesis of folate-dependent enzymes were isolated and six of them analysed. In three of the isolates reversion was the result of an intragenic suppressor mutation in the metH locus. In the remaining strains suppressor mutations occurred in independent genes.

Regulation of folate-dependent enzyme levels in Aspergillus nidulans: studies with regulatory mutants.

The synthesis of folate-dependent enzymes in Aspergillus nidulans appears to be regulated by intracellular pools of homocysteine and methionine. The results are consistent with the view that homocysteine acts as an inducer and methionine as a corepressor, but the molecular mechanism of the regulation is still unknown. Methionine-requiring mutants, metH2 and metD10, apparently allelic, show deregulation of folate-dependent enzymes.

[A method of determining global migration from plastic packing materials into model fluids simulating food products containing fat according to directives of the EWG Commission].

A method is described for determination of global migration into model fluids simulating food products with fat of isooctane, 50% and 96% ethanol from 33 samples of foils and laminates used for food packing. Bag, chamber, immersion and padding methods were used. Most samples complied with the requirements of the EEC Directives and the used method is simple and convenient.

[A method for determining global migration into model fluids from plastic packaging materials, in accordance with recommendations of the EWG commission].

Samples of polypropylene, polyethylene, polystyrene foils, softened polyvinyl chloride foils and laminates, in which polyethylene or EVA copolymer or SULRYN ionomer formed the inner layer were subjected to tests for determination of the global migration to aqueous fluids using model methods: chamber test, bag test, immersion test and lining test. The tested materials comprised 37 samples of packaging materials. The tested samples were not exceeding the range of permitted global migration into aqueous model fluids as recommended by the EEC directives.

[Formaldehyde determination in packing paper for food products by the colorimetric method with acetylacetone].

Papers used for food packing were studied for formaldehyde migration from them by the colorimetric method with acetylacetone. The studied material comprised 14 samples of paper of Polish or foreign production: pergamenous paper, offset and sulphite papers and one sample from waste paper imported from Germany. Formaldehyde migration from these samples differed but never exceeded 1 mg/dm2, with the exception of the recycled paper from which it was 1.

[Determination of unbound formaldehyde in protein coverings using the colorimetric method with chromotropic acid].

In the period 1989-1991 in a control of health quality of packing material and utility objects in contact with food 1964 samples of protein coverings for processed food were analysed, determining the content of formaldehyde, lead, arsenic and copper according to the requirements of Production Standard ZN-76/MPSS-M-19-149. It was found that in about 40% of covering samples formaldehyde level exceeded the acceptable level of 1000 mg/kg. In about 90% of the samples the level of formaldehyde was below 1800 mg/kg.

[Determination of formaldehyde content in artificial cellulose casings by the colorimetric method with acetylacetone].

Artificial cellulose casings destined for production of processed pork were studied for their ability of formaldehyde release by a colorimetric method with acetylacetone. The studied material comprised 24 samples of colourless imported cellulose casings. The migration of formaldehyde into distilled water under conditions laid down in the BGA regulations (Empfehlung XLIV) was not exceeding 0.

[Examination of plastic food-packaging materials].

The aim of the work was evaluation of the hygienic quality of plastic packaging material and its elements intended for direct contact with food products. The study carried out in the years 1986-1989 comprised 3066 samples taken from 20 provinces. A considerable number of the studied materials had no attest of the State Institute of Hygiene (19.

[Determining acebutolol level in the blood serum].

A simple method for isolation of acebutolol from blood serum, and conditions of thin-layer chromatography for detection of this drug in blood are reported. An own colorimetric method has been developed for the determination of acebutolol after its isolation and hydrolysis in the medium of sulphuric acid. Results of the determinations were subjected to statistical analysis.