scholarly journals Isolation and characterization of a myeloma–spleen-cell hybrid producing antibody to phenylalanine hydroxylase

1980 ◽  
Vol 191 (3) ◽  
pp. 777-783 ◽  
Author(s):  
R G H Cotton ◽  
I G Jennings ◽  
K H Choo ◽  
K Fowler

Application of the technique of myeloma–spleen-cell fusion [Kohler & Milstein (1975) Nature (London) 256, 495–497] has allowed the isolation of a cell colony that produced a monoclonal antibody against monkey liver phenylalanine hydroxylase. The antibody exhibited cross-reactivity against hepatic phenylalanine hydroxylase from other mammalian species, including human, rat and mouse. Cross-reactivity was established by (a) enzyme-inhibition assay, (b) double-immunodiffusion reaction, and (c) two-dimensional polyacrylamide-gel-electrophoretic analysis of immunoprecipitate. The various properties of the monoclonal antibody and its use in the study of mammalian phenylalanine hydroxylase are presented.

1985 ◽  
Vol 98 (1) ◽  
pp. 209-217 ◽  
Author(s):  
Osamu URAYAMA ◽  
Hideaki NAGAMUNE ◽  
Makoto NAKAO ◽  
Yukichi HARA ◽  
Hiroyuki SUGIYAMA ◽  
...  

2001 ◽  
Vol 56 (3-4) ◽  
pp. 402-405 ◽  
Author(s):  
H.-B. Hong ◽  
Y.-S. Chang ◽  
S.-D. Choi ◽  
I.-H. Nam ◽  
Y.-E. Lee

2002 ◽  
Vol 68 (9) ◽  
pp. 4390-4398 ◽  
Author(s):  
S. A. F. T. van Hijum ◽  
G. H. van Geel-Schutten ◽  
H. Rahaoui ◽  
M. J. E. C. van der Maarel ◽  
L. Dijkhuizen

ABSTRACT Fructosyltransferase (FTF) enzymes produce fructose polymers (fructans) from sucrose. Here, we report the isolation and characterization of an FTF-encoding gene from Lactobacillus reuteri strain 121. A C-terminally truncated version of the ftf gene was successfully expressed in Escherichia coli. When incubated with sucrose, the purified recombinant FTF enzyme produced large amounts of fructo-oligosaccharides (FOS) with β-(2→1)-linked fructosyl units, plus a high-molecular-weight fructan polymer (>107) with β-(2→1) linkages (an inulin). FOS, but not inulin, was found in supernatants of L. reuteri strain 121 cultures grown on medium containing sucrose. Bacterial inulin production has been reported for only Streptococcus mutans strains. FOS production has been reported for a few bacterial strains. This paper reports the first-time isolation and molecular characterization of (i) a Lactobacillus ftf gene, (ii) an inulosucrase associated with a generally regarded as safe bacterium, (iii) an FTF enzyme synthesizing both a high molecular weight inulin and FOS, and (iv) an FTF protein containing a cell wall-anchoring LPXTG motif. The biological relevance and potential health benefits of an inulosucrase associated with an L. reuteri strain remain to be established.


1980 ◽  
Vol 87 (3) ◽  
pp. 755-763 ◽  
Author(s):  
P A Harper ◽  
R L Juliano

Variant clones of Chinese hamster ovary (CHO) cells were selected for reduced adhesion to serum-coated tissue culture plates. These clones also displayed reduced adhesion to substrata composed of collagen layers coated with bovine serum or with fibronectin (cold-insoluble globulin). Wild-type (WT) and adhesion variant (ADv) cells grew at comparable rates in suspension culture, but the adhesion variants could not be grown in monolayer culture because of their inability to attach to the substratum. The adhesion deficit in these cells was not corrected by raising the concentration of divalent cations or of serum to levels 10-fold greater than those normally utilized in cell culture. However, both WT and ADv clones could adhere, spread, and attain a normal CHO morphology on substrata coated with concanavalin A or poly-L-lysine. In addition, the adhesion variants could attach to substrata coated with "footpad" material (substratum-attached material) derived from monolayers of human diploid fibroblasts or WT CHO cells. These observations suggest that the variant clones may have a cell surface defect that prevents them from utilizing exogeneous fibronectin as an adhesion-promoting ligand; however the variants seem to have normal cytoskeletal and metabolic capacities that allow them to attach and spread on substrata coated with alternative ligands. These variants should be extremely useful in studying the molecular basis of cell adhesion.


2005 ◽  
Vol 71 (8) ◽  
pp. 4487-4496 ◽  
Author(s):  
Yongqin Jiao ◽  
Andreas Kappler ◽  
Laura R. Croal ◽  
Dianne K. Newman

ABSTRACT We report the isolation and characterization of a phototrophic ferrous iron [Fe(II)]-oxidizing bacterium named TIE-1 that differs from other Fe(II)-oxidizing phototrophs in that it is genetically tractable. Under anaerobic conditions, TIE-1 grows photoautotrophically with Fe(II), H2, or thiosulfate as the electron donor and photoheterotrophically with a variety of organic carbon sources. TIE-1 also grows chemoheterotrophically in the dark. This isolate appears to be a new strain of the purple nonsulfur bacterial species Rhodopseudomonas palustris, based on physiological and phylogenetic analysis. Fe(II) oxidation is optimal at pH 6.5 to 6.9. The mineral products of Fe(II) oxidation are pH dependent: below pH 7.0 goethite (α-FeOOH) forms, and above pH 7.2 magnetite (Fe3O4) forms. TIE-1 forms colonies on agar plates and is sensitive to a variety of antibiotics. A hyperactive mariner transposon is capable of random insertion into the chromosome with a transposition frequency of ∼10−5. To identify components involved in phototrophic Fe(II) oxidation, mutants of TIE-1 were generated by transposon mutagenesis and screened for defects in Fe(II) oxidation in a cell suspension assay. Among approximately 12,000 mutants screened, 6 were identified that are specifically impaired in Fe(II) oxidation. Five of these mutants have independent disruptions in a gene that is predicted to encode an integral membrane protein that appears to be part of an ABC transport system; the sixth mutant has an insertion in a gene that is a homolog of CobS, an enzyme involved in cobalamin (vitamin B12) biosynthesis.


2012 ◽  
Vol 95 (2) ◽  
pp. 372-376 ◽  
Author(s):  
Elisabeth Halbmayr-Jech ◽  
Elisabeth Hammer ◽  
Richard Fielder ◽  
Jacqueline Coutts ◽  
Adrian Rogers ◽  
...  

Abstract In this work, a monoclonal antibody called G12, raised against the most immunotoxic peptide to celiac disease patients, was used to develop a sandwich ELISA. Preliminary results on cross-reactivities, recoveries, and extraction methods of the new assay are presented. The assay calibration was performed using material from the Prolamin Working Group. The antibody's specificity was determined by cross-reactivity studies on different grains, nuts, oils, and starches. Recovery of the assay was determined by spiking experiments on common food matrixes, as well as on problematic matrixes. Furthermore, sample extraction methods using ethanol, cocktail solution, and a proprietary buffer have been compared.


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