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S Neumann

Publications and source records attributed to S Neumann.

At least 19 recordsLinked to original sources
PubMed2000

Characterization of the cys gene locus from Allochromatium vinosum indicates an unusual sulfate assimilation pathway.

Homologues of the genes cysB, cysI, cysH, cysD, cysN, and selD were identified in the genome of the phototrophic purple sulfur bacterium Allochromatium vinosum (formerly Chromatium vinosum). On the basis of amino acid comparisons these genes encode a ferredoxin-dependent siroheme-sulfite reductase (CysI), a plant-type assimilatory APS reductase without thioredoxin domain (CysH), the two different subunits of heterodimeric ATP sulfurylase (CysDN), a transcriptional regulator (CysB) and a selenophosphate synthase (SelD). cysIHDN appear to form an operon and are preceded by cysB which is transcribed in the opposite direction. SelD is situated downstream of cysN and transcribed divergently to cysIHDN. The lack of a gene for APS kinase and presence of a gene for an assimilatory APS reductase implies that assimilatory sulfate reduction in A. vinosum proceeds along the pathway suggested for higher plants without intermediary formation of PAPS. Two completely separate pathways involving specialized enzymes are used for assimilatory sulfate reduction and dissimilatory sulfur oxidation in A. vinosum. The presence of cysB indicates that the genes for assimilatory sulfate reduction are expressed only in the absence of reduced sulfur compounds.

Amino Acid Sequence↗
PubMed2000

Genomic organization of the dog dystroglycan gene DAG1 locus on chromosome 20q15.1-q15.2.

Dystroglycan is a laminin binding protein, which provides a structural link between the subsarcolemmal cytoskeleton and the extracellular matrix. It is also involved in the organization of basement membranes. So far the genomic organization of the dystroglycan gene DAG1 has not been completely investigated. Here we report the cloning and sequencing of 162 kb of dog genomic DNA containing the complete approximately 71-kb canine DAG1 gene, which consists of three exons, with the translation start codon located in exon 2. Its 2679-nucleotide ORF encodes a polypeptide of 892 amino acids, which is highly similar to human, rabbit, and bovine orthologs. To further characterize the dog DAG1 gene we determined the transcription start site and several naturally occurring polymorphisms, which partially result in amino acid substitutions of the dystroglycan protein. The dog DAG1 gene was assigned to chromosome 20q15.1-q15.2 by FISH analysis. The analysis of the entire reported sequence revealed that the genes for aminomethyltransferase (AMT), bassoon (BSN), TCTA (T-cell leukemia translocation-associated) gene, and an as yet uncharacterized protein are located very close to the DAG1 gene. Therefore, this study defines a novel syntenic region among dog chromosome 20q15, human chromosome 3p21, and murine chromosome 9F.

Animals↗
PubMed1999

Regeneration of dorsal column fibers into and beyond the lesion site following adult spinal cord injury.

Regeneration is abortive following adult mammalian CNS injury. We have investigated whether increasing the intrinsic growth state of primary sensory neurons by a conditioning peripheral nerve lesion increases regrowth of their central axons. After dorsal column lesions, all fibers stop at the injury site. Animals with a peripheral axotomy concomitant with the central lesion show axonal growth into the lesion but not into the spinal cord above the lesion. A preconditioning lesion 1 or 2 weeks prior to the dorsal column injury results in growth into the spinal cord above the lesion. In vitro, the growth capacity of DRG neurite is also increased following preconditioning lesions. The intrinsic growth state of injured neurons is, therefore, a key determinant for central regeneration.

Animals↗
PubMed1999

Linkage of familial euthyroid goiter to the multinodular goiter-1 locus and exclusion of the candidate genes thyroglobulin, thyroperoxidase, and Na+/I- symporter.

Iodine deficiency is the most important etiological factor for euthyroid endemic goiter. However, family and twin pair studies also indicate a genetic predisposition for euthyroid simple goiter. In hypothyroid goiters several molecular defects in the thyroglobulin (TG), thyroperoxidase (TPO), and Na+/I- symporter (NIS) genes have been identified. The TSH receptor with its central role for thyroid function and growth is also a strong candidate gene. Therefore, we investigated a proposita with a relapsing euthyroid goiter and her family, in which several members underwent thyroidectomy for euthyroid goiter. Sequence analysis of the complementary DNA (cDNA) of the TPO and TSH receptor genes revealed several previously reported polymorphisms. As it is not possible to exclude a functional relevance for all polymorphisms, we opted for linkage analysis with microsatellite markers to investigate whether the candidate genes are involved in the pathogenesis of euthyroid goiter. The markers for the genes TG, TPO, and NIS gave two-point and multipoint logarithm of odds score analysis scores that were negative or below 1 for all assumed recombination fractions. As no significant evidence of linkage was found, we conclude that these candidate genes can be excluded as a major cause of the euthyroid goiters in this family. In contrast, we have found evidence for linkage of familial euthyroid goiter to the recently identified locus for familial multinodular nontoxic goiter (MNG-1) on chromosome 14q. The haplotype cosegregates clearly with familial euthyroid goiter. Our results provide the first confirmation for MNG-1 as a locus for nontoxic goiter.

Adolescent↗
PubMed1998

Purification and properties of the F1F0 ATPase of Ilyobacter tartaricus, a sodium ion pump.

The ATPase of Ilyobacter tartaricus was solubilized from the bacterial membranes and purified. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified enzyme revealed the usual subunit pattern of a bacterial F1F0 ATPase. The polypeptides with apparent molecular masses of 56, 52, 35, 16.5, and 6.5 kDa were identified as the alpha, beta, gamma, epsilon, and c subunits, respectively, by N-terminal protein sequencing and comparison with the sequences of the corresponding subunits from the Na(+)-translocating ATPase of Propionigenium modestum. Two overlapping sequences were obtained for the polypeptides moving with an apparent molecular mass of 22 kDa (tentatively assigned as b and delta subunits). No sequence could be determined for the putative a subunit (apparent molecular mass, 25 kDa). The c subunits formed a strong aggregate with the apparent molecular mass of 50 kDa which required treatment with trichloroacetic acid for dissociation. The ATPase was inhibited by dicyclohexyl carbodiimide, and Na+ ions protected the enzyme from this inhibition. The ATPase was specifically activated by Na+ or Li+ ions, markedly at high pH. After reconstitution into proteoliposomes, the enzyme catalyzed the ATP-dependent transport of Na+, Li+, or Hi+. Proton transport was specifically inhibited by Na+ or Li+ ions, indicating a competition between these alkali ions and protons for binding and translocation across the membrane. These experiments characterize the I. tartaricus ATPase as a new member of the family of FS-ATPases, which use Na+ as the physiological coupling ion for ATP synthesis.

Amino Acid Sequence↗