scispace - formally typeset
Search or ask a question
Topic

Lysis

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


Papers
More filters
Journal ArticleDOI
TL;DR: The purified protein interfered with the fast inactivation of thrombin clotting as well as amidolytic activity by antithrombin III-heparin complex, indicating the ability of S-protein to neutralize heparin activity.
Abstract: S-protein, the main inhibitor of the assembly of the membrane attack complex of complement, was isolated from human plasma by a simple purification procedure, which includes barium citrate adsorption, ammonium sulphate precipitation, chromatography on DEAE-Sephacel and Blue Sepharose and gel filtration on Sephacryl S-200. The homogeneous protein (sedimentation coefficient 4.6 S) was obtained in approx. 5% yield relative to its concentration in plasma, which was found to be 0.3-0.5 mg/ml. The final product did not cross-react with antisera against complement proteins or other proteinase inhibitors of human plasma. On polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate, S-protein migrated as a single-chain band with an apparent Mr of 74000 under non-reducing conditions and as a doublet of Mr 78000 and 65000 upon reduction. In plasma or serum S-protein also existed in two forms of corresponding Mr values, as was evidenced by an immunoblot enzyme-linked immunosorbent assay technique. S-protein was found to be an acidic glycoprotein with 10% (W/W) carbohydrate content and several isoelectric points in the range pH 4.75-5.25, and it contained one free thiol group per molecule of protein. The functional properties of S-protein in the complement system were demonstrated by its ability to inhibit complement-dependent cell lysis in a concentration-dependent manner (Ki 0.6 microM) and by its incorporation into the nascent SC5b-7 complex. A new function for S-protein could be revealed in the blood coagulation system. The slow progressive inhibition of thrombin by antithrombin III was not affected by S-protein, whereas the purified protein interfered with the fast inactivation of thrombin clotting as well as amidolytic activity by antithrombin III-heparin complex. The acceleration of this inhibition reaction by heparin was counteracted by S-protein, indicating the ability of S-protein to neutralize heparin activity.

170 citations

Journal ArticleDOI
TL;DR: The proposed mechanism of the bacteria inactivation by ozone that caused cell membrane destruction and finally lysis reaction is supported and the precaution of using ozone as a biocide should be used to address appropriate concentrations of bacterial contamination in water.
Abstract: Ozone appeared to inhibit growth and caused the death of gram negative and gram positive tested bacteria: Escherichia coli, Salmonella sp., Staphylococcus aureus and Bacillus subtilis. Bacterial cultures at 10(3), 10(4), 10(5), 10(6), and 10(7) cfu/ml dilution were exposed to 0.167/mg/min/L of ozone at different time intervals (0, 5, 10, 15, 30, 60, 90, 120, and 150 min). Cell viability was observed in all types of tested bacteria at 10(3), 10(4), 10(3) cfu/ml within 30 min after ozone exposure. However, cell inactivation was not significantly observed at concentrations of 10(6), 10(7) cfu/ml even after an exposure of 150 min. Ultrastructural changes of treated bacteria showed deformation, rough damage and surface destruction revealed by scanning electron microscopy. Some bacterial cells showed collapsed and shrunken patterns within 60 min and severe rupture and cellular lysis after 90 min of ozone treatment. This study supports the proposed mechanism of the bacteria inactivation by ozone that caused cell membrane destruction and finally lysis reaction. Thus, the precaution of using ozone as a biocide should be used to address appropriate concentrations of bacterial contamination in water.

169 citations

Journal ArticleDOI
TL;DR: The cell wall of exponential phase Staphylococcus aureus (strain Duncan) loses its tensile strength in c.
Abstract: SUMMARY: The cell wall of exponential phase Staphylococcus aureus (strain Duncan) loses its tensile strength in c. 2 hr. when the organisms are incubated at 25° in 1·2 m-sucrose at pH 5·8 and ionic strengtin 0·3. The ‘protoplasts’ thus released from the mechanical protection of the cell wall are stable in 1·2 m-sucrose but lyse in media of lower osmotic pressure. The mean internal osmotic pressure of the ‘protoplasts’ is c. 20 atmospheres; they are permeable to glycerol but not to sucrose or NaCl. The rate of ‘protoplast’ release varies with the rate of growth of the organisms at harvesting. After osmotic explosion of ‘protoplasts’ released from slowly growing organisms the plasma membranes may be recovered as spherical shells which disintegrate and condense into small particles on washing, and 75% of the weight of the cell walls may be recovered as hemispherical shells.

169 citations

Journal ArticleDOI
Alan T. Bull1
TL;DR: Melanin-bound chitin was extremely resistant to enzymic degradation and substrate protection by melanin in the context of its antimycolytic properties have been discussed.

168 citations

Journal ArticleDOI
TL;DR: A microfluidic sample preparation platform for rapid on-chip detection of infectious organisms for point-of-care diagnostics that isolated and detected both gram-negative and gram-positive bacterial genomic DNA from microliter scale spiked whole human blood samples.
Abstract: Sepsis caused by gram positive and gram negative bacteria is the leading cause of death in noncoronary ICUs and the tenth leading cause of death in the United States. We have developed a microfluidic sample preparation platform for rapid on-chip detection of infectious organisms for point-of-care diagnostics. The microfluidic chips are made of a robust thermoplastic and can be easily multiplexed for high throughput applications. Bacteria are lysed on-chip via hybrid chemical/mechanical method. Once lysed, the bacterial DNA is isolated using a microscale silica bead/polymer composite solid-phase-extraction (SPE) column. Lysis was confirmed using off-chip real time PCR. We isolated and detected both gram-negative (Escherichia coli) and gram-positive (Bacillussubtilis and Enterococcus faecalis) bacterial genomic DNA from microliter scale spiked whole human blood samples. The system performs better for gram-negative bacteria than it does for gram-positive bacteria, with limits of detection at 102CFU/ml and 103–104CFU/ml, respectively. Total extraction times are less than one hour and can be further decreased by altering the channel geometry and pumping configuration.

166 citations


Network Information
Related Topics (5)
Cell culture
133.3K papers, 5.3M citations
86% related
Antigen
170.2K papers, 6.9M citations
86% related
DNA
107.1K papers, 4.7M citations
86% related
Immune system
182.8K papers, 7.9M citations
84% related
Gene
211.7K papers, 10.3M citations
83% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023389
2022607
2021123
2020142
2019139
2018161