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W C Hollifield

Publications and source records attributed to W C Hollifield.

6 recordsLinked to original sources
PubMed1993

Childhood sledding injuries in 1990-91.

Sledding injuries are a common wintertime problem. To better characterize these injuries, three analyses were done: a retrospective chart review of all injured sledders at St. Louis Children's Hospital (SLCH) in the winter of 1990-91, a review of Consumer Product Safety Commission (CPSC) injury data for 1990, and measurements of sledding speeds. Analyses of the SLCH data and the CPSC data yielded similar results. Younger children incur more head injuries, while older children incur more extremity injuries. The SLCH data indicate that most injuries occur close to home when a sledder strikes a fixed object in his path. Velocities of 10 to 20 mph may be easily achieved. Injury prevention includes appropriate selection of sledding site, use of protective clothing, and refraining from sledding at times of highest risk.

Adolescent↗
PubMed1987

Efficient RecABC-dependent, homologous recombination between coliphage lambda and plasmids requires a phage ninR region gene.

A phage lambda gene that gives a 100-fold increase in recombinant frequencies for RecABC pathway-mediated, phage-plasmid homologous recombination (Shen and Huang 1986) maps to ninG (orf 204) of lambda. We call this gene rap, for recombination adept with plasmid. A similar determinant exists in Charon 4A and maps in phi 80-derived sequences, between nin5 and the Rz homology with lambda. The absence of the Rap+ phenotype from certain lambda vectors explains the inefficiency of screening the resulting phage libraries using phage-plasmid homologous recombination. The mapping of rap permits the construction of lambda vectors more suitable for this screening technique.

Bacteriophage lambda↗
PubMed1987

Syrinx 2A: an improved lambda phage vector designed for screening DNA libraries by recombination in vivo.

The Syrinx 2A phage and pi AN13 plasmid were designed for screening of DNA libraries by homologous recombination in vivo. Syrinx 2A carries multiple cloning sites and a recently identified lambda gene, rap (recombination adept with plasmid), required for efficient phage-plasmid recombination. We describe a rapid, reliable, and technically easy method to screen Syrinx 2A libraries, expand the resulting phage-plasmid cointegrates, and subclone plasmid in as little as 2 days. Recombination screening allows one specific member of a closely related multigene family to be isolated selectively.

Bacteriophage lambda↗
PubMed1978

Ferric enterobactin transport system in Escherichia coli K-12. Extraction, assay, and specificity of the outer membrane receptor.

An outer membrane preparation from cells of Escherichia coli K-12 grown in low iron medium was found to retain ferric enterobactin binding activity following solubilization in a Tris-HCl, Na2EDTA buffer containing Triton X-100. Activity was measured by means of a DEAE-cellulose column which separated free and receptor bound ferric enterobactin. The binding activity was greatly reduced in preparations obtained from cells grown in iron rich media or from cells of a colicin B resistant mutant grown in either high or low iron media. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis enabled correlation of this lack of activity to a single band missing in the outer membrane profile of the colicin B mutant. Evidence was obtained for in vitro competition between ferric enterobactin and colicin B for the extracted receptor. The binding specificity of the extracted receptor was examined by competition between ferric enterobactin and several iron chelates including a carbocyclic analogue of enterobactin, cis-1,5,9-tris(2,3-dihydroxybenzamido)cyclododecane. The ferric form of the latter compound supported growth of siderophore auxotrophs, apparently without hydrolysis to dihydroxybenzoic acid and resynthesis into enterobactin. These data may require revision of the accepted mechanism of enterobactin mediated iron utilization.

Cell Membrane↗