Topic
Lysis
About: Lysis is a research topic. Over the lifetime, 6072 publications have been published within this topic receiving 216978 citations.
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TL;DR: It is proposed that the electric field causes an irreversible loss of the membrane's function as the semipermeable barrier between the bacterial cell and its environment, and that this is the cause of cell death.
362 citations
TL;DR: It is suggested that E. coli hemolysin may damage cell membranes by partial insertion into the lipid bilayer and generation of a discrete, hydrophilic transmembrane pore with an effective diameter of approximately 3 nm, caused by the insertion of toxin monomers into the target lipid bilayers.
Abstract: Escherichia coli hemolysin is secreted as a water-soluble polypeptide of Mr 107,000. After binding to target erythrocytes, the membrane-bound toxin resembled an integral membrane protein in that it was refractory towards extraction with salt solutions of low ionic strength. Toxin-induced hemolysis could be totally inhibited by addition of 30 mM dextran 4 (mean Mr, 4,000; molecular diameter approximately 3 nm) to the extracellular medium. Uncharged molecules of smaller size (e.g., sucrose, with a molecular diameter of 0.9 nm, or raffinose, with a molecular diameter of 1.2 to 1.3 nm) did not afford such protection. Treatment of erythrocytes suspended in dextran-containing buffer with the toxin induced rapid efflux of cellular K+ and influx of 45Ca2+, as well as influx of [14C]mannitol and [3H]sucrose. [3H]inulin only slowly permeated into toxin-treated cells, and [3H]dextran uptake was virtually nil. Membranes lysed with high doses of E. coli hemolysin exhibited no recognizable ultrastructural lesions when examined by negative-staining electron microscopy. Sucrose density gradient centrifugation of deoxycholate-solubilized target membranes led to recovery of the toxin exclusively in monomer form. Incubation of toxin-treated cells with trypsin caused limited proteolysis with the generation of membrane-bound, toxin-derived polypeptides of Mr approximately 80,000 without destroying the functional pore. We suggest that E. coli hemolysin may damage cell membranes by partial insertion into the lipid bilayer and generation of a discrete, hydrophilic transmembrane pore with an effective diameter of approximately 3 nm. In contrast to the structured pores generated by cytolysins of gram-positive bacteria such as staphylococcal alpha-toxin and streptolysin O, pore formation by E. coli hemolysin may be caused by the insertion of toxin monomers into the target lipid bilayers.
353 citations
TL;DR: The simplicity, rapidity, and universality of cold methanol extraction offer great promise if a single method of lysis is to be adopted in metabolome analysis, as well as influencing quantitative analysis of particular compounds.
352 citations
TL;DR: Reliable detection of vacuoles using vital staining with fluorescent dyes in conjunction with fluorescence microscopy is described in the chapter, which describes techniques used in the study of the vacuole.
Abstract: Publisher Summary This chapter describes techniques used in the study of the vacuole and focuses on the procedures used in the laboratories. The yeast vacuole is a large, dynamic organelle that can be detected by fight microscopy. It is most prominent when cells are viewed using differential interference-contrast optics. Reliable detection of vacuoles using vital staining with fluorescent dyes in conjunction with fluorescence microscopy is described in the chapter. Several methods are available for purification of the yeast vacuole, all of which take advantage of the low buoyant density of the vacuole. The method of choice is a modified version of the procedure used by involves enzymatic removal of the cell walls, osmotic lysis of the spheroplasts, followed by flotation of the vacuoles on a discontinuous Ficoll gradient. Other methods use polybase induced lysis of spheroplasts under isotonic conditions followed by density gradient centrifugation. The procedure that follows has consistently given 10–20% yield of vacuoles and low contamination of other organelles.
351 citations
TL;DR: The results showed that analyzing wash waters is essential in quantifying biofilm EPS; the contribution of this step varied from 8-50% of the total carbohydrate yield, depending on the extraction method.
343 citations