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Biomedical subjects

H E Eipel

Publications and source records attributed to H E Eipel.

2 recordsLinked to original sources

Microbial determinations by flow cytometry.

Recent improvements in the optics and electronics of flow cytometry systems, as well as in staining techniques, permit the assay of such minute cellular constituents as the DNA and protein contents of micro-organisms. To assess the usefulness of this technique, DNA and protein content distributions were determined in Escherichia coli, Lactobacillus brevis, Lactobacillus casei, Chlorella kessleri 8k, Saccharomyces cerevisiae, Candida utilis, Schizosaccharomyces pombe and Euglena gracilis. Investigations of the DNA content distributions of polyploid strains of Saccharomyces cerevisiae indicated that the method can be used to determine ploidy. The rapidity of flow cytometry measurements allows accurate determinations in large populations.

Bacteria

Flow cytometric determinations of cellular substances in algae, bacteria, moulds and yeasts.

The practical use of flow cytometry is shown in several microbial assays. Recent technical improvements in the optics and electronics of flow cytometric systems as well as in staining techniques permit the measurements of minute cellular components such as the cellular DNA and the protein content of bacteria, algae, moulds and yeasts. Single cell ingredients can be measured by this assay according to their specific stainability. The cell DNA was stained by propidium iodide while the cell protein was fluorochromed by fluorescein-iso-thiocyanate. The DNA synthesis of Saccharomyces cerevisiae and Saccharomyces pastorianus runs discontinuously while the protein content increases continuously during the vegetative growth. The different stages of DNA synthesis of yeast cells can be divided into two 'gap' phases, a synthesis and a mitosis period, corresponding to Howard and Pelc's model of DNA synthesis. Living and dead cells can be counted differentially after staining with Erythrosine B. The red fluorescence of the chlorophyll in algae can readily be used to determine the chlorophyll content of these cells.

Bacterial Proteins