Lysis

About: Lysis is a research topic. Over the lifetime, 6072 publications have been published within this topic receiving 216978 citations.

Effect of β-Lactam Antibiotics on Bacterial Cell Growth Rate

Abstract: Summary: The effect of penicillins and cephalosporins on the rate of growth of individual cells of Escherichia coli on agar was determined by measurement of cell length using photomicrographs taken at frequent intervals. When exposed to cephalexin or carbenicillin at twice the minimum inhibitory concentration cell division was inhibited but growth in length proceeded at a uniform exponential rate until abruptly terminated by lysis. The rate of growth of such filamentous cells did not differ significantly from that of normal cells grown in the absence of antibiotic. In contrast, exposure to cephaloridine and amoxycillin at twice the minimum inhibitory concentration resulted in a marked diminution in the rate of cell growth, and lysis occurred very much sooner. At concentrations greatly in excess of the minimum inhibitory concentration (> 100-fold) cephalexin also resulted in a diminution in the rate of cell growth and this was accompanied by earlier lysis. The significance of these findings is discussed in relation to the mode of action of β-lactam antibiotics.

DNA extraction from mixtures of body fluid using mild preferential lysis.

Abstract: A modification to the DNA extraction method "preferential lysis" (Gill et al. 1985) is proposed which can be applied to DNA mixtures of vaginal cells and spermatozoa. In mixtures with a low sperm content the further loss of sperm DNA caused by the extraction can be avoided by using "mild preferential lysis". Amplification by PCR (polymerase chain reaction) then yields sufficient DNA to be able to identify both components in the mixture.

Isolation of RNA.

Abstract: Publisher Summary This chapter discusses various methods of isolating RNA. If the purification of large initial transcripts of RNA or rare RNA intermediates undergoing processing is the goal, protocols that utilize guanidium salts to solubilize tissue and denature proteins, including ribonucleases, are the methods of choice. The preparation of RNA from subcellular fractions requires procedures for gentle disruption of cells and for inhibiting nucleases during subsequent purification of the desired molecules. The cytoplasmic components contained in the supernatant fluids are suitable for analysis of polysomes, enrichment of specific RNAs by immunoisolation of polysomes, isolation of RNA-protein complexes, and purification of cytoplasmic RNAs. The pelleted nuclei are not usually used for the isolation of RNA. The isolation of nuclei or nuclear components is usually carried out to purify nuclear RNAs or RNA processing complexes or for in vitro transcription. The efficiency of cell lysis and the quality of the nuclei can be ascertained by examination of the cell suspension before and after cell lysis in a phase-contrast microscope.

A spheroplast rate assay for determination of cell wall integrity in yeast

Abstract: The rate of formation of spheroplasts of yeast can be used as an assay to study the structural integrity of cell walls. Lysis can be measured spectrophotometrically in hypotonic solution in the presence of Zymolyase, a mixture of cell wall-digesting enzymes. The optical density of the cell suspension decreases as the cells lyse. We optimized this assay with respect to enzyme concentration, temperature, pH, and growth conditions for several strains of Saccharomyces cerevisiae. The level of variability (standard deviation) was 1–5% between trials where the replications were performed on the same culture using enzyme prepared from the same lot, and 5–15% for different cultures of the same strain. This assay can quantitate differences in cell wall structure (1) between exponentially growing and stationary phase cells, (2) among different S. cerevisiae strains, (3) between S. cerevisiae and Candida albicans, (4) between parental and mutated lines, and (5) between drug- or chemically-treated cells and controls. © 1998 John Wiley & Sons, Ltd.