Biomedical subjects

K Z Abshire

Publications and source records attributed to K Z Abshire.

3 recordsLinked to original sources

PubMed1997

Escherichia coli proteome analysis using the gene-protein database.

The gene-protein database of Escherichia coli is a collection of data, largely generated from the separation of complex mixtures of cellular proteins on two-dimensional (2-D) polyacrylamide gel electrophoresis. The database currently contains about 1600 protein spots. The data are comprised of both identification information for many of these proteins and data on how the level or synthesis rates of proteins vary under different growth conditions. Three projects are underway to further elucidate the E. coli proteome including a project to localize on 2-D gels all of the open reading framed encoded by the E. coli chromosome, a project to determine the condition(s) under which each open reading frame is expressed and a project to determine the abundance and location of each protein in the cell. Applications for proteome databases for cell modeling are discussed and examples of applications in therapeutic drug discovery are given.

Bacterial Proteins↗

PubMed1993

Analysis of proteins synthesized by Salmonella typhimurium during growth within a host macrophage.

Salmonella typhimurium is a facultative intracellular pathogen, able both to invade and to survive within eukaryotic cells and to grow in various extracellular environments. To compare the bacterial responses to these disparate environments and to shed light on the nature of the intracellular environment, we have examined the pattern of protein synthesis by two-dimensional polyacrylamide gel electrophoresis. The levels of approximately 40 proteins were observed to increase during growth within macrophage-like U937 cells, while approximately 100 proteins exhibited levels that were repressed relative to those of an extracellular control culture. To aid in the interpretation of these results, the patterns of proteins made by S. typhimurium exposed to various environmental conditions in the laboratory were determined. The intracellular protein pattern was then compared with each of these benchmark protein patterns. This analysis revealed that, as expected, the intracellular environment appears to impose numerous stresses on the bacteria, but unexpectedly, the macrophage-induced response was not a simple sum of the individual stress responses displayed during extracellular growth.

Bacterial Proteins↗

PubMed1993

Growth rate paradox of Salmonella typhimurium within host macrophages.

The growth rate of Salmonella typhimurium U937 within host macrophages was estimated by two independent methods. The extent to which ribosomal protein L12 is acetylated to produce ribosomal protein L7 changes markedly with the growth rate. By this measure, the intracellular bacteria appeared to be growing rapidly. Measurements of viable bacteria, however, indicated that the bacteria were growing slowly. A solution of this apparent growth rate paradox was sought by treating U937 cells infected with S. typhimurium X3306 with ampicillin or chloramphenicol to help determine the number of bacteria that were actively growing and dividing in the intracellular condition. Use of these antibiotics showed that by 2 h after invasion, the intracellular bacteria consisted of at least two populations, one static and the other rapidly dividing. This finding implies that previously described changes in the gene expression of S. typhimurium are important for the survival and/or multiplication of the bacteria within the macrophage.

Ampicillin↗