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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: The results indicated that, in the absence of LLO, the broad-range PLC and the metalloprotease were both required for lysis of the primary vacuole in Henle 407 cells, and the efficiency of escape was reduced in an LLO phosphatidylinositol-specific PLC double mutant.
Abstract: Intracellular growth of Listeria monocytogenes begins after lysis of the primary vacuole formed upon bacterial entry into a host cell. Listeriolysin O (LLO), a pore-forming hemolysin encoded by hly, is essential for vacuolar lysis in most cell types. However, in human epithelial cells, LLO- mutants are capable of growth, suggesting that gene products other than LLO are capable of mediating escape from a vacuole. In this study, we investigated the role of other bacterial gene products in lysis of the primary vacuole in the human epithelial cell line Henle 407. Double internal in-frame deletion mutants were constructed by introducing a mutated hly allele into strains harboring deletions in either of the phospholipase C (PLC)-encoding genes or a metalloprotease-encoding gene. Bacterial escape from the primary vacuole, intracellular growth, and cell-to-cell spread were evaluated in Henle 407 cells. The results indicated that, in the absence of LLO, the broad-range PLC and the metalloprotease were both required for lysis of the primary vacuole in Henle 407 cells. Although phosphatidylinositol-specific PLC was not required, the efficiency of escape was reduced in an LLO phosphatidylinositol-specific PLC double mutant. These observations suggest that the relative importance of LLO, the phospholipases, and the metalloprotease may vary in different cell types or in cells from different species. In addition, these studies provide insight into the mechanisms of action of virulence determinants involved in the lysis of vacuolar membranes.

223 citations

Journal ArticleDOI
TL;DR: Solid-phase anti-C9 proved an efficient tool for the isolation of HRF from solubilized EH membranes and was termed homologous restriction factor (HRF), indicating that the action of this regulatory protein is species specific.
Abstract: Erythrocytes are poorly lysed by homologous complement, whereas they are readily lysed by heterologous complement. This phenomenon had been attributed to an interference by the cell surface with the action of complement components C8 and C9. To isolate the responsible membrane constituent, detergent-solubilized human erythrocyte (EH) membranes were subjected to affinity chromatography by using human C9-Sepharose. The isolated protein had a mass of 38 kDa and, incorporated into liposomes, was highly effective in inhibiting complement-mediated channel expression, including the C5b-8, membrane attack complex, and tubular polymer of C9 channels. Antibody produced to the 38-kDa protein caused a 20-fold increase in reactive lysis of EH by isolated C5b6, C7, C8, and C9. The antibody did not enhance C5b-7 uptake, but it affected C9 binding to the target cell membrane. Antibody to human decay-accelerating factor, used as a control, had no effect on reactive lysis of EH. Anti-38-kDa protein did not enhance the action on EH of C8 and C9 from other species, indicating that the action of this regulatory protein is species specific. It was therefore termed homologous restriction factor (HRF). Blood cells other than erythrocytes, such as polymorphonuclear leukocytes, also exhibited cell-surface HRF activity. In immunoblots of freshly isolated EH membranes, anti-38-kDa HRF detected primarily a 65-kDa protein, suggesting that the 38-kDa protein constitutes an active fragment of membrane HRF. Because of the specific binding reaction observed between HRF and C8 or C9, HRF was tested with anti-human C8 and anti-human C9. A limited immunochemical relationship of HRF to C8 and C9 could be established and solid-phase anti-C9 proved an efficient tool for the isolation of HRF from solubilized EH membranes.

221 citations

Journal ArticleDOI
TL;DR: The experimental observation suggests that E. coli are also lysed by the pulsed electric field, and the means of using electric field lysing can greatly simplify purification steps for preparation of biological samples compared to conventional chemical methods.
Abstract: A new micromachined cell lysis device is developed. It is designed for miniature bio-analysis systems where cell lysing is needed to obtain intracellular materials for further analysis such as DNA identification. It consists of multi-electrode pairs to apply electric fields to cells. We adopt the means of using electric field lysing because it can greatly simplify purification steps for preparation of biological samples compared to conventional chemical methods. Yeast, Chinese cabbage, radish cells and Escherichia coli are tested with the device. The lysis of yeast, Chinese cabbage and radish cells is observed by a microscope. The experimental observation suggests that E. coli are also lysed by the pulsed electric field. The range of electric field for the lysis is on the order of 1 kV/cm to 10 kV/cm. The Teflon coated on the electrodes can protect the electrodes during the pulsing period. In addition, for practical reasons, we reduce the voltage required for lysing to less than 10 V by making the electrode gap on the order of microns.

220 citations

Journal ArticleDOI
TL;DR: Melanin was found to be highly resistant to microbial degradation, a likely requirement for the polyaromatic to be effective in protecting fungal structures from lysis or decomposition by natural communities of microorganisms.
Abstract: Evidence is presented that the resistance of Aspergillus nidulans hyphae to lysis by a beta-(1-->3) glucanase-chitinase mixture results from the presence of melanin in the fungal walls. The resistance of the walls to digestion was directly correlated with the melanin content of the mycelium. A melanin-less mutant of A. nidulans was highly susceptible to hydrolysis by the enzyme mixture. Preincubation of a synthetic melanin with the glucanase, chitinase, and a protease, before addition of the substrate, resulted in a marked inhibition of the rate of substrate hydrolysis. Melanin also appeared to combine with and protect at least certain substrates from decomposition, as indicated by the direct relationship between the extent of inhibition of casein hydrolysis by a bacterial protease and the length of time the protein was incubated with the melanin prior to addition of the enzyme. Melanin was found to be highly resistant to microbial degradation, a likely requirement for the polyaromatic to be effective in protecting fungal structures from lysis or decomposition by natural communities of microorganisms.

219 citations

Journal ArticleDOI
TL;DR: The miniaturized format of this purification device, along with its excellent purification characteristics make it an ideal component for nucleic acid-based biosensors, especially those in which nucleic Acid amplification is a critical step.

218 citations


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