Various characteristics of the structure and synthesis of procollagens produced by cultured skin fibroblasts from patients with Danlos-Ehlers syndrome type I

The electrophoretic mobilities of the collagen and procollagen type I and III chains synthesized by the fibroblasts isolated from patients with type I Ehlers-Danlos syndrome as well as a set of peptides obtained by splitting of pro alpha 1(I) and pro alpha 2(I) type I procollagens by cyanbromide are not different from the normal ones. The fact demonstrates the absence of long insertions or deletions, or the sufficient defects in intracellular chain modifications. The changes were also nor registered for the ratio of type I and III collagens from the digested by pepsin preparations of protein accumulating in the culture media of the cultured skin fibroblasts from patients. The studied strains of cultured fibroblasts from patients suffering the Ehlers-Danlos syndrome have the trend to increased accumulation of partially processed chains of proc alpha 1(I) and proc alpha 2(I) type I procollagen and to the increased ratio of pro alpha 1(I) to pro alpha 2(I).     

Down's syndrome,Edwards' syndrome,Patau's syndrome —synthesis of glycosaminoglycans

Synthesis of glycosaminoglycans (GAGS) by fibroblasts derived from seven patients with Down's syndrome, five patients with Edwards' syndrome, and two patients with Patau's syndrome were studied in cell culture. The aneuploid strains were compared with diploid fibroblasts from age-matched controls. In terms of hyaluronic acid and sulfated GAG synthesis, the amount of synthesized hyaluronic acid was not significantly different between postnatal aneuploid strains and controls.     

Role of gamma-glutamyltranspeptidase in detoxification of xenobiotics in the yeasts Hansenula polymorpha and Saccharomyces cerevisiae

GGT1 gene of the methylotrophic yeast Hansenula polymorpha appears to be a structural and functional homologue of Saccharomyces cerevisiae CIS2/ECM38 gene encoding gamma-glutamyltranspeptidase (gammaGT). This is confirmed by the absence of the corresponding activity of gammaGT in the mutant with disrupted GGT1 gene. It was shown that gammaGT of both H. polymorpha and S. cerevisiae are involved in detoxification of electrophilic xenobiotics, as the corresponding mutants appeared to be defective in the disappearance of the fluorescent vacuolar complex of GSH with xenobiotic bimane and the further diffuse distribution of this complex in the cytosol. We hypothesize that metabolism of electrophilic xenobiotics in the yeasts H. polymorpha and S. cerevisiae occurs through a gammaGT-dependent mercapturic acid pathway of GSH-xenobiotic detoxification, similar to that known for mammalian cells, with cysteine-xenobiotics and/or N-acetylcysteine-xenobiotics as the end products.     

Structural analysis of the PP2C phosphatase tPphA from Thermosynechococcus elongatus: a flexible flap subdomain controls access to the catalytic site

The homologue of the phosphoprotein PII phosphatase PphA from Thermosynechococcus elongatus, termed tPphA, was identified and its structure was resolved in two different space groups, C222₁ and P4₁2₁2, at a resolution of 1.28 and 3.05 Å, respectively. tPphA belongs to a large and widely distributed subfamily of Mg²⁺/Mn²⁺-dependent phosphatases of the PPM superfamily characterized by the lack of catalytic and regulatory domains. The core structure of tPphA shows a high degree of similarity to the two PPM structures identified so far. In contrast to human PP2C, but similar to Mycobacterium tuberculosis phosphatase PstP, the catalytic centre exhibits a third metal ion in addition to the dinuclear metal centre universally conserved in all PPM members. The fact that the third metal is only liganded by amino acids, which are universally conserved in all PPM members, implies that the third metal could be general for all members of this family. As a specific feature of tPphA, a flexible subdomain, previously recognized as a flap domain, could be revealed. Comparison of different structural isomers of tPphA as well as site-specific mutagenesis implied that the flap domain is involved in substrate binding and catalytic activity. The structural arrangement of the flap domain was accompanied by a large side-chain movement of an Arg residue (Arg169) at the basis of the flap. Mutation of this residue strongly impaired protein stability as well as catalytic activity, emphasizing the importance of this amino acid for the regional polysterism of the flap subdomain and confirming the assumption that flap domain flexibility is involved in catalysis.     

The role of soluble acids from oxidative-hydrolytic breakdown of coal in the development of the fibrous process in anthracosis

The oxidative-hydrolytic mechanism of interaction of coal with tissue medium and the formation of humic acids (HA) and polycarboxylic acids (PCA) from coal in the organism were demonstrated. The composition of PCA obtained from the coal withdrawn from the organism of animals was investigated by gas-liquid chromatography by means of which 28 acids of the aromatic series were identified. The method of elemental spectral analysis revealed the transition of a number of macro- and microelements into the medium of the organism. It has been shown experimentally that the decrease in the mass of coal correlates with the fibrogenic process. The conclusion has been drawn that the soluble products of the oxidative-hydrolytic breakdown of coal in the organism are among the fibrogenic factors of pneumosclerosis in anthracosis. The initial mechanism in the development of fibrosis is the damage caused by polycarboxylic acids to the microcirculatory bed of the lungs and the structures of the aerohematic barrier.     

Oxidative Stress Induces Mitochondrial Dysfunction in a Subset of Autism Lymphoblastoid Cell Lines in a Well-Matched Case Control Cohort

There is increasing recognition that mitochondrial dysfunction is associated with the autism spectrum disorders. However, little attention has been given to the etiology of mitochondrial dysfunction or how mitochondrial abnormalities might interact with other physiological disturbances associated with autism, such as oxidative stress. In the current study we used respirometry to examine reserve capacity, a measure of the mitochondrial ability to respond to physiological stress, in lymphoblastoid cell lines (LCLs) derived from children with autistic disorder (AD) as well as age and gender-matched control LCLs. We demonstrate, for the first time, that LCLs derived from children with AD have an abnormal mitochondrial reserve capacity before and after exposure to increasingly higher concentrations of 2,3-dimethoxy-1,4-napthoquinone (DMNQ), an agent that increases intracellular reactive oxygen species (ROS). Specifically, the AD LCLs exhibit a higher reserve capacity at baseline and a sharper depletion of reserve capacity when ROS exposure is increased, as compared to control LCLs. Detailed investigation indicated that reserve capacity abnormalities seen in AD LCLs were the result of higher ATP-linked respiration and maximal respiratory capacity at baseline combined with a marked increase in proton leak respiration as ROS was increased. We further demonstrate that these reserve capacity abnormalities are driven by a subgroup of eight (32%) of 25 AD LCLs. Additional investigation of this subgroup of AD LCLs with reserve capacity abnormalities revealed that it demonstrated a greater reliance on glycolysis and on uncoupling protein 2 to regulate oxidative stress at the inner mitochondria membrane. This study suggests that a significant subgroup of AD children may have alterations in mitochondrial function which could render them more vulnerable to a pro-oxidant microenvironment derived from intrinsic and extrinsic sources of ROS such as immune activation and pro-oxidant environmental toxicants. These findings are consistent with the notion that AD is caused by a combination of genetic and environmental factors.     

Characteristics of intracellular metabolism of procollagen and other proteins in human embryo fibroblasts in trisomy for chromosome 7

A comparative study of the relative rates of intracellular total protein metabolism in diploid and aneuploid (with trisomy for chromosome 7) human embryo fibroblasts in the logarithmic and stationary growth phases was carried out. Using double labeling with [14C]proline (24 hrs) and [3H]proline (3 hrs), it was found that: the rates of intracellular protein metabolism during transition to the stationary phase of growth are increased in diploid cells and decreased in cells with trisomy for chromosome 7; the relative rate of protein metabolism in the logarithmic phase is higher in trisomic cells than in diploid ones. The intracellular degradation of procollagen in trisomic cells is increased approximately by 17% as compared to normal fibroblasts. Treatment of cell lysates with bacterial collagenase revealed the presence of procollagen incomplete degradation products in anomalous fibroblasts. The observed differences in the rates and mode of protein metabolism during transition of diploid and trisomic fibroblasts to the stationary phase of growth suggest that the odd autosome interferes with the normal coordinated activity of genes in chromosomes.