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D W Niesel

Publications and source records attributed to D W Niesel.

43 records · Page 3Linked to original sources
PubMed1984

Purification and characterization of the naturally occurring allelic variants of sn-glycerol-3-phosphate dehydrogenase in Drosophila melanogaster.

The naturally occurring electrophoretic variants of sn-glycerol-3-phosphate dehydrogenase and a heterodimeric form of the enzyme resulting from a genetic cross of two variant strains of Drosophila were purified to homogeneity by a combination of DEAE-cellulose chromatography and 8-(6-aminohexyl)-amino-ATP-Sepharose affinity chromatography. Each purified protein was compared with respect to a number of physicochemical and kinetic properties. All forms of the enzyme were found to be similar, except for pI differences associated with the electrophoretic variation observed.

Amino Acids↗
PubMed1983

Expression of hydroxamate and phenolate siderophores by Shigella flexneri.

Shigella flexneri strains were assayed for the ability to synthesize and utilize phenolate and hydroxamate siderophores. The hydroxamate aerobactin was synthesized by all isolates tested, whereas phenolates were only rarely produced. Expression of aerobactin was accompanied by production of a single iron-regulated outer membrane protein (Mr = 74,000). This protein was not produced by a mutant defective in aerobactin utilization and may serve as the aerobactin receptor. Phenolate (enterobactin)-producing strains synthesized three additional outer membrane proteins (Mr = 74,000, 81,000, and 83,000) in response to iron starvation. These proteins are the same apparent size as those produced by Escherichia coli K-12 strains. Ent sequences are apparently present in strains which do not synthesize this compound. Although normally silent, ent genes can be activated in Ent- strains to produce Ent+ variants. These laboratory variants are phenotypically indistinguishable from clinical Ent+ isolates.

Bacterial Outer Membrane Proteins↗
PubMed1982

Structural analysis of adult and larval isozymes of sn-glycerol-3-phosphate dehydrogenase of Drosophila melanogaster.

Compositional analysis of the soluble tryptic peptides representing about 70% of the 293 residues of sn-glycerol-3-phosphate dehydrogenase in Drosophila melanogaster reveals a single peptide difference between the sn-glycerol-3-phosphate dehydrogenase adult (GPDHF-1) and larval (GPDHF-3) isozymes. This peptide was shown to be the carboxyl terminus by sequence determination and by carboxypeptidase A digestion of the native protein. For GPDHF-1, the sequence of the COOH-terminal tryptic peptide is Asn-His-Pro-Glu-His-Met-Gln-Asn-Leu-COOH, while that of GPDHF-3 is Asn-His-Pro-Glu-His-Met-COOH.

Amino Acid Sequence↗
PubMed1981

Avian reticuloendotheliosis virus: identification of the hematopoietic target cell for transformation.

Non-virus-producing hematopoietic cells transformed in vitro by reticuloendotheliosis virus (REV-T) induce lethal "reticuloendotheliosis" when inoculated into histocompatible chickens. This is the first direct demonstration that an in vivo target cell of an avian acute leukemia virus can be transformed in vitro. The tumorigenic, REV-T-transformed non-virus-producing cells fail to express helper-virus-coded proteins. REV-T transformed tumorigenic cells therefore do not require helper-virus functions. Cells transformed in vivo or in vitro by REV-T have lymphoblastoid morphology and express low levels of terminal-deoxynucleotidyl-transferase activity and bursal-cell determinants. One clone synthesized Ig mu. The preferred target cells for REV-T transformation are therefore immature lymphoid cells that express B-cell determinants. We propose that the unique transforming sequence of REV-T be designated rel (lymphoid).

Animals↗
PubMedDate not supplied

Enhancement by calcium of the invasiveness of Salmonella for HeLa cell monolayers.

An outer membrane-associated cytotoxin and the invasive capacity of Salmonella were shown to be modulated by divalent cations. Cell detachment activity of salmonella cytotoxin was blocked by addition of either Ca++ or Mg++. It is interesting that Ca++ but not other divalent cations was shown to enhance the invasiveness of Salmonella for HeLa cell monolayers. The dose-dependent Ca++ effect required metabolism and was not simply the result of Ca++ binding to the surface of the bacteria. These data suggest a possible role of divalent cations in the unique relationship of invasive bacteria and host cells.

Calcium↗
PubMedDate not supplied

Characterization of an antiviral agent from primary murine fibroblast cultures: murine tissue culture CVI.

We have previously described a class of virus inhibitors which are produced spontaneously by many types of cells in culture and present in a number of physiological fluids. These inhibitors are differentiated from all other known naturally occurring antiviral substances in regard to their (i) lack of species specificity, (ii) broad antiviral activity (iii) absence of high affinity binding by the inhibitor to the virus, (iv) mechanism of the action of the inhibitor is through inhibition of viral attachment, and (v) extreme thermal stability. In this report, we show that this class of inhibitors can be divided into two distinct subclasses. The first category includes the inhibitor spontaneously produced by cells in culture, originally described as contact-blocking viral inhibitor (CVI), and has a polypeptide component associated with its antiviral activity. The second category includes the inhibitors detected in body fluids and tissue extracts and has no essential peptide structure. Further characterization of CVI with respect to molecular size and stability to heat and a number of chemical reagents and enzymes indicate that the antiviral activity of CVI is associated with a large molecule (90s or approximately 4 million daltons), is stable at 100(8)C, and is resistant to the action of RNase, DNase, sulfhydral reagents, protein denaturants, and extraction by organic solvents.

Animals↗