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K C Hall

Publications and source records attributed to K C Hall.

3 recordsLinked to original sources
PubMed1992

DNA sequences and characterization of dtxR alleles from Corynebacterium diphtheriae PW8(-), 1030(-), and C7hm723(-).

The structural gene encoding DtxR, an iron-dependent diphtheria tox regulatory element, has recently been cloned and sequenced from the C7(-) strain of Corynebacterium diphtheriae (J. M. Boyd, M. Oza, and J. R. Murphy, Proc. Natl. Acad. Sci. USA 87:5972, 1990). We report here the molecular cloning, DNA sequence analysis, and characterization of DtxR from the PW8(-), 1030(-), and C7hm723 strains of C. diphtheriae. While the sequence of dtxR from PW8(-) is identical to that of the C7(-) allele, the sequence of dtxR from the 1030(-) strain is only 91.4% identical; however, the deduced amino acid sequence of DtxR from 1030(-) differs by only 6 of 678 amino acids. Moreover, DtxR from all three strains is shown to regulate expression of beta-galactosidase from a tox promoter-operator (toxPO)-lacZ transcriptional fusion. In contrast, the dtxR allele from the iron-insensitive tox constitutive mutant C7hm723 was found to have a single G----A transition, resulting in a substitution of Arg-47 to His and the loss of tox regulatory activity in recombinant Escherichia coli.

Alleles↗
PubMed1985

Evaluation readiness: improved evaluation planning using a data inventory framework.

Factors intrinsic to many programs, such as ambiguously stated objectives, inadequately defined performance measures, and incomplete or unreliable databases, often conspire to limit the evaluability of these programs. Current evaluation planning approaches are somewhat constrained in their ability to overcome these obstacles and to achieve full preparedness for evaluation. In this paper, the concept of evaluation readiness is introduced as a complement to other evaluation planning approaches, most notably that of evaluability assessment. The basic products of evaluation readiness--the formal program definition and the data inventory framework--are described, along with a guide for assuring more timely and appropriate evaluation response capability to support the decision making needs of program managers. The utility of evaluation readiness for program planning, as well as for effective management, is also discussed.

Evaluation Studies as Topic↗