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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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Journal ArticleDOI
TL;DR: A new method based upon the direct lysis of cells in the sediment, extraction of released DNA from the sediments and its subsequent purification by CsCL-EtBr gradient centrifugation and/or hydroxyapatite chromatography is developed.

696 citations

Journal ArticleDOI
TL;DR: It is shown that penicillins bind to all six proteins but that at least some cephalosporins fail to bind, or bind very slowly, to proteins 2, 5 and 6, although they bind to the other proteins.
Abstract: Benzyl[14C]penicillin binds to six proteins with molecular weights between 40000 and 91000 in the inner membrane of Escherichia coli. Two additional binding proteins with molecular weights of 29000 and 32000 were sometimes detected. All proteins were accessible to benzyl[14C]penicillin in whole cells. Proteins 5 and 6 released bound benzyl[14C]penicillin with half times of 5 and 19 min at 30 degrees C but the other binding proteins showed less than 50% release during a 60-min period at 30 degrees C. The rate of release of bound penicillin from some of the proteins was greatly stimulated by 2-mercaptoethanol and neutral hydroxylamine. Release of benzyl[14C]penicillin did not occur if the binding proteins were denatured in anionic detergent and so was probably enzymic. No additional binding proteins were detected with two [14C]cephalosporins. These beta-lactams bound to either all or some of those proteins to which benzyl[14C]penicillin bound. No binding proteins have been detected in the outer membrane of E coli with any beta-[14C]lactam. The binding of a range of unlabelled penicillins and cephalosporins were studied by measuring their competition for the binding of benzyl[14C]penicillin to the six penicillin-binding proteins. These results, together with those obtained by direct binding experiments with beta-[14C]lactams, showed that penicillins bind to all six proteins but that at least some cephalosporins fail to bind, or bind very slowly, to proteins 2, 5 and 6, although they bind to the other proteins. Since these cephalosporins inhibited cell division and caused cell lysis at concentrations where we could detect no binding to proteins 2, 5 and 6, we believe that these latter proteins are not the target at which beta-lactams bind to elicit the above physiological responses. The binding properties of proteins 1, 3, and 4 correlate reasonably well with those expected for the above killing targets.

671 citations

Journal ArticleDOI
TL;DR: An enzymatic iodination procedure utilizing lactoperoxidase, radioactive iodide, and hydrogen peroxide generated by a glucose oxidase-glucose system has been described and utilized for a study of the red cell membrane.
Abstract: An enzymatic iodination procedure utilizing lactoperoxidase (LPO), radioactive iodide, and hydrogen peroxide generated by a glucose oxidase-glucose system has been described and utilized for a study of the red cell membrane. 97% of the incorporated isotope is in the erythrocyte ghost and 3% is associated with hemoglobin. No significant labeling of the red cell membrane occurs in the absence of LPO or by the deletion of any of the other reagents. A 6 million-fold excess of chloride ions inhibits iodination by no more than 50%. Incorporation of up to 1 x 106 iodide atoms into a single erythrocyte membrane results in no significant cell lysis. The incorporated label is exclusively in tyrosine residues as monoiodotyrosine. 10–15% of the trichloroacetic acid-precipitable radioactivity can be extracted with lipid solvents but is present as either labeled protein or 125I. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of solubilized membrane proteins reveals only two labeled protein bands out of the 15 present, and the presence of 50-1 x 106 iodide atoms per ghost does not alter this pattern. Component a has a molecular weight of 110,000, is carbohydrate poor, and represents 40% of the total label. Component b has an apparent molecular weight of 74,000, contains all of the demonstrable sialic acid, and accounts for 60% of the total label. Trypsinization of iodinated, intact red cells results in the disappearance of only component b, the appearance of labeled glycopeptides in the medium, and the absence of smaller, labeled peptides remaining in the membrane. Pronase treatment hydrolyzes component b in a similar fashion, but also cleaves component a to a 72,000 mol wt peptide which is retained in the membrane. A combination of protease treatment and double labeling with 125I and 131I does not reveal the appearance of previously unexposed proteins.

660 citations

Journal ArticleDOI
TL;DR: In this article, the authors show that extracellular DNA in different culture conditions favors apoptosis or spontaneous active DNA release in non-dividing cells, such as lymphocytes, frog auricles and cultured cell lines including HL-60, spontaneously release a nucleoprotein complex within a homeostatic system.

658 citations

Journal ArticleDOI
TL;DR: It was demonstrated that the superoxide free radical per se was not the agent causing lysis, and evidence is presented that the free radical causing the lysis of the lysosomes is the hydroxyl free radical (OH·).

644 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023389
2022607
2021123
2020142
2019139
2018161