Lysis

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

Lysis and Lysis Inhibition with Escherichia coli Bacteriophage

Abstract: The present understanding of genetic principles has emerged only after exhaustive study of numerous organisms characterized by various levels of organization. Recently the trend has been toward investigations with the simpler organisms as is illustrated by work with fungi (Beadle, 1945a, 1945b; Lindegren, 1945) and several of the protista (Moewus, 1940; Sonneborn, 1946). Analysis of the pattern of mutability has made even the bacteria amenable to genetic investigation (Luria and Delbriick, 1943). Genetic studies have, however, been made with organisms at an even lower level of organization than those mentioned above. Luria (1945) with his experiments on host range mutants and Hershey (1946a, 1946b) with his analysis of plaque size mutants have cleared the way for a more complete inquiry into the genetics of the bacteriophages. Research into the genetics of these organisms may lead to the solution of genetic problems, which other studies have not yet resolved. Those bacterial viruses which have been most thoroughly investigated genetically belong to a group of seven phages and their mutant forms that comprise the T system (Delbrtick, 1946). These phages, named Ti, T2, ... and T7, fall into several subgroups on the basis of serology, electron microscopy, host range, and certain physiological characteristics. One of these subgroups is of particular interest here, the even-numbered phages, T2, T4, and T6. These phages are closely related serologically and show the same characteristic morphology in the electron microscope (Delbruick, 1946). Hershey (1946a, 1946b) has shown that they also have another property in common: all three are capable of mutation from the wild type, r+, to the r type. The former type is characterized by the fact that it forms small plaques with very turbid halos on agar plates. The mutant type, r, forms large plaques with clear. halos. Another characteristic distinguishing r+ from r type, and probably the basic cause of the plaque size difference, is the time required for lysis of visibly turbid cultures. When highly diluted, suspensions of infected bacteria have the same latent period between infection and lysis whether the phage used for infection be of the r+ or the r type. When, however, the infected cultures are visibly turbid, a difference in the latent period occurs. An r-infected culture will clear between 21 and 30 minutes after infection. In contrast to this, a visibly turbid culture infected with r+ phage will not clear between 21 and 30 minutes but will

Homologous species restriction in lysis of human erythrocytes: a membrane-derived protein with C8-binding capacity functions as an inhibitor.

Abstract: An intrinsic membrane protein with a m.w. of 65,000 that can bind human C8 has been identified after separation of human erythrocyte membrane proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and electrotransfer to nitrocellulose sheets. The protein, tentatively designated as the C8-binding protein (C8bp) could be isolated from papain-treated erythrocyte (E) membranes by phenol-water extraction and isoelectric focusing. In a functional assay, with chicken (ch) E as target cells, C8bp inhibited the lysis of ch E C5b67 intermediates by human C8 and C9, whereas the lysis by rabbit C8 and C9 was not affected. Because the decay accelerating factor (DAF) from human erythrocyte membranes also inhibits the activity of C3/C5 convertases in an homologous system, we tested whether or not a DAF activity was present in C8bp. C8bp, however, did not accelerate the decay of the classic C3 convertases. Thus, it appears that C8bp and DAF are two different factors of E membranes with a similar molecular size inhibiting different sites of the activation cascade of complement while they can function synergistically to minimize the self-inflicted damage by complement.

Preparation of genomic DNA from plant tissue.

Abstract: This unit describes two methods for preparing genomic DNA from plant tissue. In the first method, plant cells are lysed with ionic detergent, treated with protease, and subsequently purified by cesium chloride (CsCl) density gradient centrifugation. The second method is based upon a series of treatments with the nonionic detergent cetyltrimethylammonium bromide (CTAB) to lyse cells and purify nucleic acid. Nucleic acid is recovered from the final CTAB solution by isopropanol or ethanol precipitation. The first method, although somewhat more lengthy, results in highly purified nucleic acid. The second method requires fewer manipulations, results in very high yields (approximately 10-fold higher per gram fresh tissue depending on species and condition of starting material), and produces DNA that is less pure but nonetheless suitable in quality for use in many molecular biology manipulations.