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9 results on '"Burgess, B. W."'

6. The PS2 integrin ligand tiggrin is required for proper muscle function in Drosophila.

Author

Bunch, T A, Graner, M W, Fessler, L I, Fessler, J H, Schneider, K D, Kerschen, A, Choy, L P, Burgess, B W, and Brower, D L

Abstract

Tiggrin is a novel extracellular matrix ligand for the Drosophila PS2 integrins. We have used flanking P elements to generate a precise deletion of tiggrin. Most flies lacking tiggrin die as larvae or pupae. A few adults do emerge and these appear to be relatively normal, displaying only misshapen abdomens and a low frequency of wing defects. Examination of larvae shows that muscle connections, function and morphology are defective in tiggrin mutants. Muscle contraction waves that extend the length of the larvae are much slower in tiggrin mutants. Direct examination of bodywall muscles shows defects in muscle attachment sites, where tiggrin is specifically localized, and muscles appear thinner. Transgenes expressing tiggrin are capable of rescuing tiggrin mutant phenotypes. Transgenes expressing a mutant tiggrin, whose Arg-Gly-Asp (RGD) integrin recognition sequence has been mutated to Leu-Gly-Ala (LGA) show much reduced, but significant, rescuing ability. Cell spreading assays detect no interactions of this mutant tiggrin with PS2 integrins. Therefore, while the RGD sequence is critical for PS2 interactions and full activity in the whole fly, the mutant tiggrin retains some function(s) that are probably mediated by interactions with other ECM molecules or cell surface receptors

Published
1998

7. Production of leptin in Escherichia coli: a comparison of methods.

Author

Varnerin JP, Smith T, Rosenblum CI, Vongs A, Murphy BA, Nunes C, Mellin TN, King JJ, Burgess BW, Junker B, Chou M, Hey P, Frazier E, MacIntyre DE, Van der Ploeg LH, and Tota MR

Subjects
Animals, Biological Assay, Cell Line, Endotoxins analysis, Escherichia coli genetics, Filtration, Genetic Vectors genetics, Humans, Inclusion Bodies chemistry, Leptin, Mice, Mice, Mutant Strains, Mice, Obese, Peptides chemistry, Proteins chemistry, Proteins isolation & purification, Proteins pharmacology, Radioimmunoassay, Recombinant Fusion Proteins biosynthesis, Recombinant Fusion Proteins chemistry, Recombinant Fusion Proteins isolation & purification, Recombinant Fusion Proteins pharmacology, Weight Loss drug effects, Histidine, Protein Biosynthesis, Protein Folding
Abstract

A procedure is described for gram-scale refolding of Escherichia coli-derived human leptin inclusion bodies. Refolding was achieved by gradually reducing denaturant using a diafiltration method. Refolded leptin is characterized by in vivo modulation of food intake, reduction in body weight, and lowering of insulin and glucose levels in ob/ob mice. In addition, refolded leptin is characterized by radioimmunoassay (RIA) and activation of the leptin receptor in a cell-based assay. For comparison we also refolded leptin by a simple dilution method and produced periplasmic derived leptin, which did not require ex vivo folding. Leptin produced by these three methods and leptin obtained from commercial sources were compared using the RIA and the cell-based assay and appeared to be of comparable quality and potency., (Copyright 1998 Academic Press.)

Published
1998
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8. Additional cochinmicins from a Microbispora sp.

Author

Lam YK, Zink DL, Williams DL Jr, and Burgess BW

Subjects
Bacteria drug effects, Chemical Phenomena, Chemistry, Physical, Fermentation, Magnetic Resonance Spectroscopy, Molecular Structure, Peptides, Cyclic biosynthesis, Peptides, Cyclic pharmacology, Endothelins antagonists & inhibitors, Micromonosporaceae metabolism, Peptides, Cyclic chemistry
Published
1992
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9. Physiological effects of TGF(alpha)-PE40 expression in recombinant Escherichia coli JM109.

Author

George HA, Powell AL, Dahlgren ME, Herber WK, Maigetter RZ, Burgess BW, Stirdivant SM, and Greasham RL

Abstract

Physiological effects of isopropyl-thiogalactopyranoside (IPTG) induction were examined in Escherichia coli strain JM109 expressing a fusion protein composed of transforming growth factor alpha and a 40-kD portion of Pseudomonas aeruginosa exotoxin A (TGF(alpha)-PE40) under control of the tac promoter. Fermentations at the 15-L scale in complex medium compared growth and metabolite profiles of the untransformed JM109 host strain, the strain transformed with the vector lacking the TGF(alpha)-PE40 open reading frame (JM109[pKK2.7]), and the strain with the complete plasmid for TGF(alpha)-PE40 expression (JM109[pTAC-TGF57-PE40]). Metabolite and growth profiles of JM109 (pTAC-TGF57-PE40) cultures changed significantly in IPTG-induced versus uninduced cultures. Prior to induction, glucose was metabolized to acetate or completely oxidized to CO(2). Following induction, pyruvate was also excreted in addition to acetate. In the absence of inducer, pyruvate was excreted by JM109 (pTAC-TGF57-PE40) only when dissolved oxygen levels fell to less than 10% of saturation (microaerobic rather than anaerobic conditions). The untransformed JM109 host strain or JM109 (pKK2.7) did not excrete pyruvate in the presence or absence of inducer, although JM109 (pKK2.7) exhibited a pattern of growth following addition of IPTG that closely resembled JM109 (pTAC-TFG57-PE40). Fermentations of JM109 (pTAC-TFG57-PE40) in a synthetic medium supported lower expression levels, but resulted in similar alterations in metabolite profiles. Induction in synthetic medium resulted in pyruvate excretion without further acetate accumulation. Taken together, these data suggest that one consequence of TGF(alpha)-PE40 expression in JM109 is altered patterns of pyruvate oxidation., ((c) 1992 John Wiley & Sons, Inc.)

Published
1992
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