Biomedical subjects

N K Davis

Publications and source records attributed to N K Davis.

8 recordsLinked to original sources

PubMed1995

Assessing elderly acute care services: improving quality amid chaos.

Elderly service delivery within the medical-surgical division of a large midwestern tertiary care center was assessed to explore how to meet better the special needs and address the complex situations that older adults present. Twenty-seven nursing staff members working in the four medical-surgical units and the medical intensive care unit were interviewed using participant observation and unstructured interviewing methods as they delivered care to older adults. The following categories emerged from the qualitative data analysis: problems related to the care of older adults, causes of confusion, effective and potentially effective interventions for older patients, and staff educational needs. A major suggestion was to develop an interdisciplinary seniors team to provide consultation on issues related to older adults to nursing staff, medical staff, and other interdisciplinary staff involved in patient care. The team would evaluate the appropriateness of interventions, equipment, and personnel use related to older adults as well as identify and develop quality assurance activities to monitor and evaluate the care delivered to older adults.

Aged↗

PubMed1993

Transgenic animals as tools in drug development.

A transgenic animal can be defined as an organism that has undergone a stable modification of genotype as a result of genetic manipulation. Such animals are being increasingly employed as research and development tools by both academic and commercial institutions. The primary methods by which transgenic animals can be generated will be described. The relative merits of the approaches will be illustrated, as will their potential use in the discovery and development of novel therapeutic entities.

Animals↗

PubMed1992

The Streptomyces coelicolor whiB gene encodes a small transcription factor-like protein dispensable for growth but essential for sporulation.

A non-sporulating mutant (whiB218) of Streptomyces coelicolor A3(2), which proved to contain a deletion of more than 5 kb of DNA including whiB, was complemented by a small cloned DNA fragment, deduced from DNA sequencing to encode a protein of only 87 amino acids. This protein would bear some similarities to transcription factors, including an acidic, somewhat amphipathic alpha-helical region predicted near its N-terminus, and a basic alpha-helical region predicted at its C-terminus. A point mutation (whiB70) giving a phenotype indistinguishable from that of the whiB218 deletion mutant would cause a leucine to proline change at the start of the latter region. The whiB homologue from the closely related species S. lividans differed at only one base from its S. coelicolor counterpart, and would specify an identical polypeptide.

Amino Acid Sequence↗

PubMed1990

Spore colour in Streptomyces coelicolor A3(2) involves the developmentally regulated synthesis of a compound biosynthetically related to polyketide antibiotics.

Streptomyces coelicolor produces spores whose development of a grey colour requires the activity of the whiE locus. The cloned whiE locus was identified after mobilization into a whiE mutant of a library of S. coelicolor DNA inserted into a transmissible plasmid vector. The whiE region of the cloned DNA was localized both by subcloning and by mutagenesis of the cloned DNA with the Streptomyces transposon Tn4560. Nucleotide sequencing of this region revealed seven open reading frames, of which six show homology at the level of deduced gene products with genes involved in the synthesis of polyketide antibiotics. A previously described S. coelicolor DNA segment encoding biosynthesis of a brown pigment (Horinouchi and Beppu, 1985) corresponds to the cloned whiE DNA. It is proposed that whiE is normally expressed only in the aerial hyphae, where the biosynthetic product is responsible for spore colour.

Amino Acid Sequence↗

PubMed1989

Cloning and structural characterization of the genes coding for adenosylcobalamin-dependent methylmalonyl-CoA mutase from Propionibacterium shermanii.

The structural genes coding for both subunits of adenosylcobalamin-dependent methylmalonyl-CoA mutase from the Gram-positive bacterium Propionibacterium shermanii have been cloned, with the use of synthetic oligonucleotides as primary hybridization probes. The genes are closely linked and are transcribed in the same direction. Nucleotide sequence analysis of 4.5 kb of DNA encompassing both genes allowed us to infer the complete amino acid sequence of the two subunits: the beta-subunit is the product of the upstream gene, and consists of 638 amino acid residues (Mr 69465) and the alpha-subunit consists of 728 amino acid residues (Mr 80,147). There is a very close structural homology between the two subunits, reflecting the probable duplication of a common ancestral gene. A sequence present only in the alpha-subunit is significantly homologous to a portion of the sequence of the methylmalonyl-CoA-binding subunit of transcarboxylase from P. shermanii [Samols, Thornton, Murtif, Kumar, Haase & Wood (1988) J. Biol. Chem. 263, 6461-6464], and this homologous region may form part of the CoA ester-binding site in both enzymes.

Amino Acid Sequence↗

PubMed1986

The subunit structure of methylmalonyl-CoA mutase from Propionibacterium shermanii.

5'-Deoxyadenosylcobalamin-dependent methylmalonyl-CoA mutase was purified to homogeneity from Propionibacterium shermanii by a simplified procedure. The native enzyme has an apparent Mr of 165,000, similar to the enzyme from other sources but larger than previously reported. It consists of two non-identical subunits, of Mr 79,000 and 67,000 respectively. The smaller subunit is apparently not a proteolytic fragment of the larger one. The final preparation usually contained some inactive mutase, bearing a tenaciously bound cobalamin species. This protein proved to be readily separable from apoenzyme by fast protein liquid chromatography on anion-exchange columns.

Amino Acids↗

PubMed1982

Isolation and mapping of glutathione reductase-negative mutants of Escherichia coli K12.

Two independent mutants defective in glutathione reductase (EC 1.6.4.2) were isolated in an Escherichia coli K12 strain lysogenized with bacteriophage Mu. The prophage was lost (and the ability to reduce glutathione regained) by 32% of the xylose-positive transductants when T4GT7 was used as the vector, but the markers were not cotransduced by P1. Similarly, the prophage site and malA were cotransduced by T4GT7 but not by P1. The gor gene maps between min 77 and 78 on the E. coli genome, and the mutation causes no growth defect.

Bacteriophage mu↗

PubMedDate not supplied

Analyzing jobs for redesign decisions.

Job analysis, the collection and interpretation of information that describes job behaviors and activities performed by occupants of jobs, can provide nurse administrators with valuable information for redesigning effective and efficient systems of care.

Data Collection↗