Dimethyl adipimidate: a new antisickling agent.
A new approach to the prevention of sickling in vitro by use of the bifunctional crosslinking reagent, dimethyl adipimidate, is described. Prior treatment of sickle erythrocytes with dimethyl adipimidate will inhibit sickling in completely deoxygenated erythrocytes. Treated erythrocytes do not demonstrate the potassium loss and viscosity increase that usually accompany sickling. The oxygen affinity of hemoglobin in these cells is increased independently from changes in the concentration of 2,3-diphosphoglycerate. The hemoglobin obtained from treated erythrocytes contains a high-molecular-weight component as well as additional positively charged components. The relative degree to which chemical modification and/or crosslinking is an essential part of the antisickling properties of the material is not known. (+info)
In vitro cytotoxicity of textile paint components linked to the "Ardystil syndrome".
The spraying of a paint formula (Acramin F system) had led to severe pulmonary disease in textile printing sprayers in Spain and Algeria (Ardystil syndrome). In order to elucidate the underlying mechanisms of the toxicity of this paint and its main polymeric components, Acramin FWR, Acramin FWN, Acrafix FHN, and Acramoll W, we have undertaken studies using a battery of different cell-types and assessing in vitro cytotoxicity by measuring LDH leakage. This study shows that, as in in vivo studies, the three polycationic paint components, Acramin FWR (a polyurea), Acramin FWN (a polyamide-amine), and Acrafix FHN (a polyamine) exhibited considerable cytotoxicity (LC50 generally below 100 microg/ml for an incubation of 20-24 h) in vitro, while Acramoll W, which is not a polycation, was almost non-toxic (in the concentration range tested). The cytotoxicity was comparable in primary cultures of rat and human type II pneumocytes and alveolar macrophages as well as in the pulmonary cell line A549 and the hepatic cell line HepG2. In human erythrocytes, the toxicity was less pronounced. We speculate that the multiple positive charges play an important role in the toxic mechanism. It is concluded that Acramin FWR and Acramin FWN have similar intrinsic toxicity and that these polymeric compounds, which have no irritant properties or systemic toxicity when given orally, exert a high, unexpected, degree of cytotoxicity. (+info)
Desulfovirga adipica gen. nov., sp. nov., an adipate-degrading, gram-negative, sulfate-reducing bacterium.
A novel, mesophilic, Gram-negative bacterium was isolated from an anaerobic digestor for municipal wastewater. The bacterium degraded adipate in the presence of sulfate, sulfite, thiosulfate and elemental sulfur. (E)-2-Hexenedioate accumulated transiently in the degradation of adipate. (E)-2-Hexenedioate, (E)-3-hexenedioate, pyruvate, lactate, C1-C12 straight-chain fatty acids and C2-C10 straight-chain primary alcohols were also utilized as electron donors. 3-Phenylpropionate was oxidized to benzoate. The G + C content of the DNA was 60 mol%. 16S rDNA sequence analysis revealed that the new isolate clustered with species of the genus Syntrophobacter and Desulforhabdus amnigenus. Strain TsuAS1T resembles Desulforhabdus amnigenus DSM 10338T with respect to the ability to utilize acetate as an electron donor and the inability to utilize propionate without sulfate in co-culture with Methanospirillum hungatei DSM 864. Strains TsuAS1T and DSM 10338T form a 'non-syntrophic subcluster' within the genus Syntrophobacter. Desulfovirga adipica gen. nov., sp. nov. is proposed for the newly isolated bacterium, with strain TsuAS1T (= DSM 12016T) as the type strain. (+info)
Characterization of a second tfd gene cluster for chlorophenol and chlorocatechol metabolism on plasmid pJP4 in Ralstonia eutropha JMP134(pJP4).
Within the 5.9-kb DNA region between the tfdR and tfdK genes on the 2,4-dichlorophenoxyacetic acid (2,4-D) catabolic plasmid pJP4 from Ralstonia eutropha JMP134, we identified five open reading frames (ORFs) with significant homology to the genes for chlorocatechol and chlorophenol metabolism (tfdCDEF and tfdB) already present elsewhere on pJP4. The five ORFs were organized and assigned as follows: tfdD(II)C(II)E(II)F(II) and tfdB(II) (in short, the tfd(II) cluster), by analogy to tfdCDEF and tfdB (the tfd(I) cluster). Primer extension analysis of mRNA isolated from 2,4-D-grown R. eutropha JMP134 identified a single transcription start site in front of the first gene of the cluster, tfdD(II), suggesting an operon-like organization for the tfd(II) genes. By expressing each ORF in Escherichia coli, we confirmed that tfdD(II) coded for a chloromuconate cycloisomerase, tfdC(II) coded for a chlorocatechol 1, 2-dioxygenase, tfdE(II) coded for a dienelactone hydrolase, tfdF(II) coded for a maleylacetate reductase, and tfdB(II) coded for a chlorophenol hydroxylase. Dot blot hybridizations of mRNA isolated from R. eutropha JMP134 showed that both tfd(I) and tfd(II) genes are transcribed upon induction with 2,4-D. Thus, the functions encoded by the tfd(II) genes seem to be redundant with respect to those of the tfd(I) cluster. One reason why the tfd(II) genes do not disappear from plasmid pJP4 might be the necessity for keeping the regulatory genes for the 2,4-D pathway expression tfdR and tfdS. (+info)
Genetic analysis of a gene cluster for cyclohexanol oxidation in Acinetobacter sp. Strain SE19 by in vitro transposition.
Biological oxidation of cyclic alcohols normally results in formation of the corresponding dicarboxylic acids, which are further metabolized and enter the central carbon metabolism in the cell. We isolated an Acinetobacter sp. from an industrial wastewater bioreactor that utilized cyclohexanol as a sole carbon source. A cosmid library was constructed from Acinetobacter sp. strain SE19, and oxidation of cyclohexanol to adipic acid was demonstrated in recombinant Escherichia coli carrying a SE19 DNA segment. A region that was essential for cyclohexanol oxidation was localized to a 14-kb fragment on the cosmid DNA. Several putative open reading frames (ORFs) that were expected to encode enzymes catalyzing the conversion of cyclohexanol to adipic acid were identified. Whereas one ORF showed high homology to cyclohexanone monooxygenase from Acinetobacter sp. strain NCIB 9871, most of the ORFs showed only moderate homology to proteins in GenBank. In order to assign functions of the various ORFs, in vitro transposon mutagenesis was performed using the cosmid DNA as a target. A set of transposon mutants with a single insertion in each of the ORFs was screened for cyclohexanol oxidation in E. coli. Several of the transposon mutants accumulated a variety of cyclohexanol oxidation intermediates. The in vitro transposon mutagenesis technique was shown to be a powerful tool for rapidly assigning gene functions to all ORFs in the pathway. (+info)
Identification in Saccharomyces cerevisiae of two isoforms of a novel mitochondrial transporter for 2-oxoadipate and 2-oxoglutarate.
The nuclear genome of Saccharomyces cerevisiae encodes 35 members of a family of membrane proteins. Known members transport substrates and products across the inner membranes of mitochondria. We have localized two hitherto unidentified family members, Odc1p and Odc2p, to the inner membranes of mitochondria. They are isoforms with 61% sequence identity, and we have shown in reconstituted liposomes that they transport the oxodicarboxylates 2-oxoadipate and 2-oxoglutarate by a strict counter exchange mechanism. Intraliposomal adipate and glutarate and to a lesser extent malate and citrate supported [14C]oxoglutarate uptake. The expression of Odc1p, the more abundant isoform, made in the presence of nonfermentable carbon sources, is repressed by glucose. The main physiological roles of Odc1p and Odc2p are probably to supply 2-oxoadipate and 2-oxoglutarate from the mitochondrial matrix to the cytosol where they are used in the biosynthesis of lysine and glutamate, respectively, and in lysine catabolism. (+info)
Key aromatic-ring-cleaving enzyme, protocatechuate 3,4-dioxygenase, in the ecologically important marine Roseobacter lineage.
Aromatic compound degradation in six bacteria representing an ecologically important marine taxon of the alpha-proteobacteria was investigated. Initial screens suggested that isolates in the Roseobacter lineage can degrade aromatic compounds via the beta-ketoadipate pathway, a catabolic route that has been well characterized in soil microbes. Six Roseobacter isolates were screened for the presence of protocatechuate 3,4-dioxygenase, a key enzyme in the beta-ketoadipate pathway. All six isolates were capable of growth on at least three of the eight aromatic monomers presented (anthranilate, benzoate, p-hydroxybenzoate, salicylate, vanillate, ferulate, protocatechuate, and coumarate). Four of the Roseobacter group isolates had inducible protocatechuate 3, 4-dioxygenase activity in cell extracts when grown on p-hydroxybenzoate. The pcaGH genes encoding this ring cleavage enzyme were cloned and sequenced from two isolates, Sagittula stellata E-37 and isolate Y3F, and in both cases the genes could be expressed in Escherichia coli to yield dioxygenase activity. Additional genes involved in the protocatechuate branch of the beta-ketoadipate pathway (pcaC, pcaQ, and pobA) were found to cluster with pcaGH in these two isolates. Pairwise sequence analysis of the pca genes revealed greater similarity between the two Roseobacter group isolates than between genes from either Roseobacter strain and soil bacteria. A degenerate PCR primer set targeting a conserved region within PcaH successfully amplified a fragment of pcaH from two additional Roseobacter group isolates, and Southern hybridization indicated the presence of pcaH in the remaining two isolates. This evidence of protocatechuate 3, 4-dioxygenase and the beta-ketoadipate pathway was found in all six Roseobacter isolates, suggesting widespread abilities to degrade aromatic compounds in this marine lineage. (+info)
Identification of the human mitochondrial oxodicarboxylate carrier. Bacterial expression, reconstitution, functional characterization, tissue distribution, and chromosomal location.
In Saccharomyces cerevisiae, the genes ODC1 and ODC2 encode isoforms of the oxodicarboxylate carrier. They both transport C5-C7 oxodicarboxylates across the inner membranes of mitochondria and are members of the family of mitochondrial carrier proteins. Orthologs are encoded in the genomes of Caenorhabditis elegans and Drosophila melanogaster, and a human expressed sequence tag (EST) encodes part of a closely related protein. Information from the EST has been used to complete the human cDNA sequence. This sequence has been used to map the gene to chromosome 14q11.2 and to show that the gene is expressed in all tissues that were examined. The human protein was produced by overexpression in Escherichia coli, purified, and reconstituted into phospholipid vesicles. It has similar transport characteristics to the yeast oxodicarboxylate carrier proteins (ODCs). Both the human and yeast ODCs catalyzed the transport of the oxodicarboxylates 2-oxoadipate and 2-oxoglutarate by a counter-exchange mechanism. Adipate, glutarate, and to a lesser extent, pimelate, 2-oxopimelate, 2-aminoadipate, oxaloacetate, and citrate were also transported by the human ODC. The main differences between the human and yeast ODCs are that 2-aminoadipate is transported by the former but not by the latter, whereas malate is transported by the yeast ODCs but not by the human ortholog. In mammals, 2-oxoadipate is a common intermediate in the catabolism of lysine, tryptophan, and hydroxylysine. It is transported from the cytoplasm into mitochondria where it is converted into acetyl-CoA. Defects in human ODC are likely to be a cause of 2-oxoadipate acidemia, an inborn error of metabolism of lysine, tryptophan, and hydroxylysine. (+info)