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Sample records for microbeam-induced cell lysis

  1. Microfluidic device for acoustic cell lysis

    Science.gov (United States)

    Branch, Darren W.; Cooley, Erika Jane; Smith, Gennifer Tanabe; James, Conrad D.; McClain, Jaime L.

    2015-08-04

    A microfluidic acoustic-based cell lysing device that can be integrated with on-chip nucleic acid extraction. Using a bulk acoustic wave (BAW) transducer array, acoustic waves can be coupled into microfluidic cartridges resulting in the lysis of cells contained therein by localized acoustic pressure. Cellular materials can then be extracted from the lysed cells. For example, nucleic acids can be extracted from the lysate using silica-based sol-gel filled microchannels, nucleic acid binding magnetic beads, or Nafion-coated electrodes. Integration of cell lysis and nucleic acid extraction on-chip enables a small, portable system that allows for rapid analysis in the field.

  2. Pressure-mediated reduction of ultrasonically induced cell lysis

    International Nuclear Information System (INIS)

    Ciaravino, V.E.; Miller, M.W.; Carstensen, E.L.

    1981-01-01

    Chinese hamster V-79 cells, exposed in polystyrene tubes for 5 min to 1-MHz continuous-wave ultrasound, were lysed more by a 10 than a 5 W/cm 2 intensity. Higher atmospheric pressure was needed to eliminate lysis with the former relative to the latter intensity, but lysis by 10 W/cm 2 was completely climinated with 2 atm of hydrostatic pressure. The reduction in lysis per unit increase in atmospheric pressure was comparable for both ultrasound intensities

  3. Urea enhances cell lysis of Schizosaccharomyces pombe ura4 mutants.

    Science.gov (United States)

    Nishino, Kohei; Kushima, Misaki; Kaino, Tomohiro; Matsuo, Yasuhiro; Kawamukai, Makoto

    2017-07-01

    Cell lysis is induced in Schizosaccharomyces pombe ∆ura4 cells grown in YPD medium, which contains yeast extract, polypeptone, and glucose. To identify the medium components that induce cell lysis, we first tested various kinds of yeast extracts from different suppliers. Cell lysis of ∆ura4 cells on YE medium was observed when yeast extracts from OXOID, BD, Oriental, and Difco were used, but not when using yeast extract from Kyokuto. To determine which compounds induced cell lysis, we subjected yeast extract and polypeptone to GC-MS analysis. Ten kinds of compounds were detected in OXOID and BD yeast extracts, but not in Kyokuto yeast extract. Among them was urea, which was also present in polypeptone, and it clearly induced cell lysis. Deletion of the ure2 gene, which is responsible for utilizing urea, abolished the lytic effect of urea. The effect of urea was suppressed by deletion of pub1, and a similar phenotype was observed in the presence of polypeptone. Thus, urea is an inducer of cell lysis in S. pombe ∆ura4 cells.

  4. Squamous cell carcinoma complicating an hereditary epidermo-lysis bullosa

    International Nuclear Information System (INIS)

    Mseddi, M.; Turki, H.; Marrekchi, S.; Abdelmaksoud, W.; Masmoudi, A.; Bouassida, S.; Zahaf, A.

    2004-01-01

    The dystrophic form of hereditary epidermo-lysis bullosa is associated with an increased frequency of squamous cell carcinoma. We report a new case. An 18-year-old patient, carrying a Hallopeau Siemens hereditary epidermo-lysis bullosa, presented a subcutaneous nodular lesion, for 1 year that ulcerated and budded with inguinal lymphadenopathy. The histological study ted to the conclusion of a well differentiated squamous cell carcinoma. The patient was treated surgically. Tumor and metastatic lymph nodes were excised. A radiotherapy was decided but the postoperative course was fatal due to an infection and to a deterioration of her general condition. Squamous cell carcinoma frequently occurs on the cicatricial lesion of hereditary epidermo-lysis bullosa and usually affects males with recessive hereditary epidermo-lysis bullosa. Metastases are frequent, precocious and multiple. The treatment may be surgical. The particularities of our observation are the young age of patient and the localization. (author)

  5. effect of natural blue-green algal cells lysis on freshwater quality

    African Journals Online (AJOL)

    Compaq

    released into water due to algal cells lysis was performed by placing samples in two ... Keywords; Algae, cells lysis, Fatty acids, gas chromatography time-of-flight mass spectrometry, water quality ... Factors such as municipal and industrial.

  6. Lab-on-a-Disc Platform for Automated Chemical Cell Lysis.

    Science.gov (United States)

    Seo, Moo-Jung; Yoo, Jae-Chern

    2018-02-26

    Chemical cell lysis is an interesting topic in the research to Lab-on-a-Disc (LOD) platforms on account of its perfect compatibility with the centrifugal spin column format. However, standard procedures followed in chemical cell lysis require sophisticated non-contact temperature control as well as the use of pressure resistant valves. These requirements pose a significant challenge thereby making the automation of chemical cell lysis on an LOD extremely difficult to achieve. In this study, an LOD capable of performing fully automated chemical cell lysis is proposed, where a combination of chemical and thermal methods has been used. It comprises a sample inlet, phase change material sheet (PCMS)-based temperature sensor, heating chamber, and pressure resistant valves. The PCMS melts and solidifies at a certain temperature and thus is capable of indicating whether the heating chamber has reached a specific temperature. Compared to conventional cell lysis systems, the proposed system offers advantages of reduced manual labor and a compact structure that can be readily integrated onto an LOD. Experiments using Salmonella typhimurium strains were conducted to confirm the performance of the proposed cell lysis system. The experimental results demonstrate that the proposed system has great potential in realizing chemical cell lysis on an LOD whilst achieving higher throughput in terms of purity and yield of DNA thereby providing a good alternative to conventional cell lysis systems.

  7. Lab-on-a-Disc Platform for Automated Chemical Cell Lysis

    Directory of Open Access Journals (Sweden)

    Moo-Jung Seo

    2018-02-01

    Full Text Available Chemical cell lysis is an interesting topic in the research to Lab-on-a-Disc (LOD platforms on account of its perfect compatibility with the centrifugal spin column format. However, standard procedures followed in chemical cell lysis require sophisticated non-contact temperature control as well as the use of pressure resistant valves. These requirements pose a significant challenge thereby making the automation of chemical cell lysis on an LOD extremely difficult to achieve. In this study, an LOD capable of performing fully automated chemical cell lysis is proposed, where a combination of chemical and thermal methods has been used. It comprises a sample inlet, phase change material sheet (PCMS-based temperature sensor, heating chamber, and pressure resistant valves. The PCMS melts and solidifies at a certain temperature and thus is capable of indicating whether the heating chamber has reached a specific temperature. Compared to conventional cell lysis systems, the proposed system offers advantages of reduced manual labor and a compact structure that can be readily integrated onto an LOD. Experiments using Salmonella typhimurium strains were conducted to confirm the performance of the proposed cell lysis system. The experimental results demonstrate that the proposed system has great potential in realizing chemical cell lysis on an LOD whilst achieving higher throughput in terms of purity and yield of DNA thereby providing a good alternative to conventional cell lysis systems.

  8. Chemical Cell Lysis System Applicable to Lab-on-a-Disc.

    Science.gov (United States)

    Lim, Dayeseul; Yoo, Jae Chern

    2017-09-01

    The design and fabrication of a heating system has been a significant challenge in implementing chemical lysis on a lab-on-a-disc (LOD). The proposed system contains a sample inlet, phase change material (PCM) array, heating chamber, and valve in a single disc, providing cost-effective, rapid, and fully automated chemical cell lysis. Compared to the conventional cell lysis system, our cell lysis system has many advantages, such as a compact structure that is easily integrated into the LOD and reduced processing time and labor. The experiments are conducted with Salmonella typhimurium strains to demonstrate the performance. The experimental results show that the proposed approach is greatly effective in realizing a chemical cell lysis system on an LOD with higher throughput in terms of purity and yield of DNA.

  9. Reagentless mechanical cell lysis by nanoscale barbs in microchannels for sample preparation.

    Science.gov (United States)

    Di Carlo, Dino; Jeong, Ki-Hun; Lee, Luke P

    2003-11-01

    A highly effective, reagentless, mechanical cell lysis device integrated in microfluidic channels is reported. Sample preparation, specifically cell lysis, is a critical element in 'lab-on-chip' applications. However, traditional methods of cell lysis require purification steps or complicated fabrication steps that a simple mechanical method of lysis may avoid. A simple and effective mechanical cell lysis system is designed, microfabricated, and characterized to quantify the efficiency of cell lysis and biomolecule accessibility. The device functionality is based on a microfluidic filter region with nanostructured barbs created using a modified deep reactive ion etching process. Mechanical lysis is characterized by using a membrane impermeable dye. Three main mechanisms of micro-mechanical lysis are described. Quantitative measurements of accessible protein as compared to a chemically lysed sample are acquired with optical absorption measurements at 280 and 414 nm. At a flow rate of 300 microL min(-1) within the filter region total protein and hemoglobin accessibilities of 4.8% and 7.5% are observed respectively as compared to 1.9% and 3.2% for a filter without nanostructured barbs.

  10. Hypochlorite- and hypobromite-mediated radical formation and its role in cell lysis

    DEFF Research Database (Denmark)

    Hawkins, C L; Brown, B E; Davies, Michael Jonathan

    2001-01-01

    . In this study it is shown that HOBr induces red blood cell lysis at approximately 10-fold lower concentrations than HOCl, whereas with monocyte (THP1) and macrophage (J774) cells HOCl and HOBr induce lysis at similar concentrations. The role of radical formation during lysis has been investigated by EPR spin...... trapping, and it is shown that reaction of both oxidants with each cell type generates cell-derived radicals. Red blood cells exposed to nonlytic doses of HOCl generate novel nitrogen-centered radicals whose formation is GSH dependent. In contrast, HOBr gives rise to nitrogen-centered, membrane......-derived protein radicals. With lytic doses of either oxidant, protein (probably hemoglobin)-derived, nitrogen-centered radicals are observed. Unlike the red blood cells, treatment of monocytes and macrophages with HOCl gives significant radical formation only under conditions where cell lysis occurs concurrently...

  11. Microfluidic systems and methods for transport and lysis of cells and analysis of cell lysate

    Science.gov (United States)

    Culbertson, Christopher T [Oak Ridge, TN; Jacobson, Stephen C [Knoxville, TN; McClain, Maxine A [Knoxville, TN; Ramsey, J Michael [Knoxville, TN

    2008-09-02

    Microfluidic systems and methods are disclosed which are adapted to transport and lyse cellular components of a test sample for analysis. The disclosed microfluidic systems and methods, which employ an electric field to rupture the cell membrane, cause unusually rapid lysis, thereby minimizing continued cellular activity and resulting in greater accuracy of analysis of cell processes.

  12. Low-Cost Energy-Efficient 3-D Nano-Spikes-Based Electric Cell Lysis Chips

    KAUST Repository

    Riaz, Kashif

    2017-05-04

    Electric cell lysis (ECL) is a promising technique to be integrated with portable lab-on-a-chip without lysing agent due to its simplicity and fast processing. ECL is usually limited by the requirements of high power/voltage and costly fabrication. In this paper, we present low-cost 3-D nano-spikes-based ECL (NSP-ECL) chips for efficient cell lysis at low power consumption. Highly ordered High-Aspect-Ratio (HAR). NSP arrays with controllable dimensions were fabricated on commercial aluminum foils through scalable and electrochemical anodization and etching. The optimized multiple pulse protocols with minimized undesirable electrochemical reactions (gas and bubble generation), common on micro parallel-plate ECL chips. Due to the scalability of fabrication process, 3-D NSPs were fabricated on small chips as well as on 4-in wafers. Phase diagram was constructed by defining critical electric field to induce cell lysis and for cell lysis saturation Esat to define non-ECL and ECL regions for different pulse parameters. NSP-ECL chips have achieved excellent cell lysis efficiencies ηlysis (ca 100%) at low applied voltages (2 V), 2~3 orders of magnitude lower than that of conventional systems. The energy consumption of NSP-ECL chips was 0.5-2 mJ/mL, 3~9 orders of magnitude lower as compared with the other methods (5J/mL-540kJ/mL). [2016-0305

  13. Radiation-induced enhancement of enzymatic cell lysis of Micrococcus radiodurans

    International Nuclear Information System (INIS)

    Watanabe, H.; Takehisa, M.; Iizuka, H.

    1981-01-01

    The intact cells of M. radiodurans were rendered sensitive to the action of lytic enzyme (P2-2 enzyme) by irradiation. The radiation-induced enhancement of cell lysis with P2-2 enzyme was completely prevented by the addition of t-butanol and irradiation at liquid nitrogen temperature. These results indicate that the enhancement is due to indirect action resulting from OH radicals. Cell lysis by lysozyme was enhanced only when the cells were irradiated under N 2 O. The enhancement of cell lysis with lysozyme was also prevented by adding alcohols. On the other hand, when lipid components in cells were removed by extraction with n-butanol, the radiation-induced enhancement of cell lysis with P2-2 enzyme and lysozyme was not observed. From these results it is concluded that the enhancement of enzymatic cell lysis by irradiation is attributable to alteration in the lipid-rich layer of the cell wall caused by OH radicals

  14. Radiation-induced enhancement of enzymatic cell lysis of Micrococcus radiodurans

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, H.; Takehisa, M. [Japan Atomic Energy Research Inst., Takasaki, Gunma, Takasaki Radiation Chemistry Research Establishment (Japan); Iizuka, H.

    1981-10-15

    The intact cells of M. radiodurans were rendered sensitive to the action of lytic enzyme (P2-2 enzyme) by irradiation. The radiation-induced enhancement of cell lysis with P2-2 enzyme was completely prevented by the addition of t-butanol and irradiation at liquid nitrogen temperature. These results indicate that the enhancement is due to indirect action resulting from OH radicals. Cell lysis by lysozyme was enhanced only when the cells were irradiated under N{sub 2}O. The enhancement of cell lysis with lysozyme was also prevented by adding alcohols. On the other hand, when lipid components in cells were removed by extraction with n-butanol, the radiation-induced enhancement of cell lysis with P2-2 enzyme and lysozyme was not observed. From these results it is concluded that the enhancement of enzymatic cell lysis by irradiation is attributable to alteration in the lipid-rich layer of the cell wall caused by OH radicals.

  15. Micro Corona Ionizer as an Ozone Source for Bacterial Cell Lysis

    Science.gov (United States)

    Lee, Eun-Hee; Lim, Hyun Jeong; Chua, Beelee; Son, Ahjeong

    2015-04-01

    DNA extraction is a critical process of DNA assays including polymerase chain reaction (PCR), microarrays, molecular cloning, and DNA hybridization which has been well established and can be implemented by commercial kits. DNA extraction involves cell lysis, precipitation, and purification through the combination of physical and chemical processes. Cell lysis is essential to high DNA recovery yield which can be achieved via a variety of physical, chemical, and enzymatic methods. However, these methods were originally developed for bioassays that were labor intensive, time consuming, and vulnerable to contamination and inhibition. Here, we proposed to employ a micro corona ionizer as an ozone source to lyse bacterial cells. Ozone has been well known and used as a disinfectant which allows cell lysis and DNA extraction. Previously, we have shown that a micro corona ionizer is capable of generating a significant amount of ozone. In this study, we employed the micro corona ionizer for the bacterial cell lysis which consists of a 50 μm diameter cantilever wire as the discharge cathode and a 50 μm thick copper foil as anode. Applied voltages varied from 1900 to 2200 V with corresponding corona currents from 16 to 28 μA. The resultant ozone (concentration > 0.14 ppm) generated from the micro corona ionizer was bubbled into the sample via a miniature pump. We demonstrated the cell lysis of Pseudomonas putida as the target bacterium using the micro corona ionizer. At a flow rate of 38 ml/min and applied corona voltage of 2000 V, 98.5 ± 0.2% lysis (normalized to sonication result) was achieved after 10 min. In comparison, untreated and air-treated samples showed normalized % lysis of 11.9 ± 2.4 and 36.1 ± 1.7%, respectively. We also showed that the cell lysis efficiency could be significantly increased by increasing the flow rate and the applied corona voltage. By comparing the experimental results for continuous and pulsed treatment, we verified that the percentage of

  16. Cell-density-dependent lysis and sporulation of Myxococcus xanthus in agarose microbeads.

    OpenAIRE

    Rosenbluh, A; Nir, R; Sahar, E; Rosenberg, E

    1989-01-01

    Vegetative cells of Myxococcus xanthus were immobilized in 25-microns-diameter agarose microbeads and incubated in either growth medium or sporulation buffer. In growth medium, the cells multiplied, glided to the periphery, and then filled the beads. In sporulation buffer, up to 90% of the cells lysed and ca. 50% of the surviving cells formed resistant spores. A strong correlation between sporulation and cell lysis was observed; both phenomena were cell density dependent. Sporulation proficie...

  17. Rapid kinetics of lysis in human natural cell-mediated cytotoxicity: some implications

    International Nuclear Information System (INIS)

    Bloom, E.T.; Babbitt, J.T.

    1983-01-01

    The entire lytic process of natural cell-mediated cytotoxicity against sensitive target cells can occur rapidly, within minutes. This was demonstrated by 51 chromium release and in single-cell assays. At the cellular level, most of the target cell lysis occurred within 15-30 min after binding to effector cells. The enriched natural killer cell subpopulation of lymphocytes obtained by Percoll density gradient centrifugation (containing greater than 70% large granular lymphocytes (LGL)) was the most rapidly lytic population by 51 chromium release. However, in the single-cell assay, the rate of lysis of bound target cells was quite similar for the LGL-enriched effector subpopulation and the higher density subpopulation of effector cells recognized previously. Both the light and dense effector cells contained similar numbers of target binding cells. Therefore, that the light subpopulation effected lysis more rapidly and to a greater extent than the dense subpopulation suggested that the low-density effector cells probably recycled more rapidly than those of higher density. This was corroborated by the finding that when conjugates were formed at 29 degrees C for the single-cell assay, a significant number of dead unconjugated targets could be observed only on the slides made with the LGL-enriched effector cells but not on those made with dense effector cell. Lysis continued to increase in the chromium-release assay probably because of recycling, recruitment, and/or heterogeneity of the effector cells, and/or because of heterogeneity or delayed death of the target cells

  18. Low-Cost Energy-Efficient 3-D Nano-Spikes-Based Electric Cell Lysis Chips

    KAUST Repository

    Riaz, Kashif; Leung, Siu; Fan, Zhiyong; Lee, Yi-Kuen

    2017-01-01

    Electric cell lysis (ECL) is a promising technique to be integrated with portable lab-on-a-chip without lysing agent due to its simplicity and fast processing. ECL is usually limited by the requirements of high power/voltage and costly fabrication

  19. Integration of nanoparticle cell lysis and microchip PCR for one-step rapid detection of bacteria.

    Science.gov (United States)

    Wan, Weijie; Yeow, John T W

    2012-04-01

    This paper describes an integrated microchip system as an efficient and cost-effective solution involving Nanotechnology and Lab-on-a-Chip technology for the rapid detection of bacteria. The system is based on using surface-modified gold nanoparticles for efficient cell lysis followed by microchip PCR without having to remove the nanoparticles from the PCR solution. Poly(quaternary ammonium) modified gold nanoparticles are used to provide a novel and efficient cell lysis method without the need to go through time-consuming, expensive and complicated microfabrication processes as most of current cell lysis methods for Lab-on-a-Chip applications do. It also facilitates the integration of cell lysis and PCR by sharing the same reaction chamber as PCR uses. It is integrated with a prototype microchip PCR system consisting of a physical microchip PCR device and an automated temperature control mechanism. The research work explores solutions for the problem of PCR inhibition caused by gold nanoparticles as well as for the problem of non-specific PCR amplification in the integrated microchip system. It also explores the possibility of greatly reducing PCR cycling time to achieve the same result compared to the protocol for a regular PCR machine. The simplicity of the setup makes it easy to be integrated with other Lab-on-a-Chip functional modules to create customized solutions for target applications.

  20. HLA-E-expressing pluripotent stem cells escape allogeneic responses and lysis by NK cells.

    Science.gov (United States)

    Gornalusse, Germán G; Hirata, Roli K; Funk, Sarah E; Riolobos, Laura; Lopes, Vanda S; Manske, Gabriel; Prunkard, Donna; Colunga, Aric G; Hanafi, Laïla-Aïcha; Clegg, Dennis O; Turtle, Cameron; Russell, David W

    2017-08-01

    Polymorphisms in the human leukocyte antigen (HLA) class I genes can cause the rejection of pluripotent stem cell (PSC)-derived products in allogeneic recipients. Disruption of the Beta-2 Microglobulin (B2M) gene eliminates surface expression of all class I molecules, but leaves the cells vulnerable to lysis by natural killer (NK) cells. Here we show that this 'missing-self' response can be prevented by forced expression of minimally polymorphic HLA-E molecules. We use adeno-associated virus (AAV)-mediated gene editing to knock in HLA-E genes at the B2M locus in human PSCs in a manner that confers inducible, regulated, surface expression of HLA-E single-chain dimers (fused to B2M) or trimers (fused to B2M and a peptide antigen), without surface expression of HLA-A, B or C. These HLA-engineered PSCs and their differentiated derivatives are not recognized as allogeneic by CD8 + T cells, do not bind anti-HLA antibodies and are resistant to NK-mediated lysis. Our approach provides a potential source of universal donor cells for applications where the differentiated derivatives lack HLA class II expression.

  1. HLA-E-expressing pluripotent stem cells escape allogeneic responses and lysis by NK cells

    Science.gov (United States)

    Gornalusse, Germán G.; Hirata, Roli K.; Funk, Sarah; Riolobos, Laura; Lopes, Vanda S.; Manske, Gabriel; Prunkard, Donna; Colunga, Aric G.; Hanafi, Laïla-Aïcha; Clegg, Dennis O.; Turtle, Cameron; Russell, David W.

    2017-01-01

    Polymorphisms in the human leukocyte antigen (HLA) class I genes can cause the rejection of pluripotent stem cell (PSC)-derived products in allogeneic recipients. Disruption of the Beta-2 Microglobulin (B2M) gene eliminates surface expression of all class I molecules, but leaves the cells vulnerable to lysis by natural killer (NK) cells. Here we show that this ‘missing self’ response can be prevented by forced expression of minimally polymorphic HLA-E molecules. We use adeno-associated virus (AAV)-mediated gene editing to knock in HLA-E genes at the B2M locus in human PSCs in a manner that confers inducible, regulated, surface expression of HLA-E single-chain dimers (fused to B2M) or trimers (fused to B2M and a peptide antigen), without surface expression of HLA-A, B or C. These HLA-engineered PSCs and their differentiated derivatives are not recognized as allogeneic by CD8+ T cells, do not bind anti-HLA antibodies, and are resistant to NK-mediated lysis. Our approach provides a potential source of universal donor cells for applications where the differentiated derivatives lack HLA class II expression. PMID:28504668

  2. A simple and novel modification of comet assay for determination of bacteriophage mediated bacterial cell lysis.

    Science.gov (United States)

    Khairnar, Krishna; Sanmukh, Swapnil; Chandekar, Rajshree; Paunikar, Waman

    2014-07-01

    The comet assay is the widely used method for in vitro toxicity testing which is also an alternative to the use of animal models for in vivo testing. Since, its inception in 1984 by Ostling and Johansson, it is being modified frequently for a wide range of application. In spite of its wide applicability, unfortunately there is no report of its application in bacteriophages research. In this study, a novel application of comet assay for the detection of bacteriophage mediated bacterial cell lysis was described. The conventional methods in bacteriophage research for studying bacterial lysis by bacteriophages are plaque assay method. It is time consuming, laborious and costly. The lytic activity of bacteriophage devours the bacterial cell which results in the release of bacterial genomic material that gets detected by ethidium bromide staining method by the comet assay protocol. The objective of this study was to compare efficacy of comet assay with different assay used to study phage mediated bacterial lysis. The assay was performed on culture isolates (N=80 studies), modified comet assay appear to have relatively higher sensitivity and specificity than other assay. The results of the study showed that the application of comet assay can be an economical, time saving and less laborious alternative to conventional plaque assay for the detection of bacteriophage mediated bacterial cell lysis. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Mass entrapment and lysis of Mesodinium rubrum cells in mucus threads observed in cultures with Dinophysis

    DEFF Research Database (Denmark)

    Ojamäe, Karin; Hansen, Per Juel; Lips, Inga

    2016-01-01

    The entrapment and death of the ciliate Mesodinium rubrum in the mucus threads in cultures with Dinophysis is described and quantified. Feeding experiments with different concentrations and predator–prey ratios of Dinophysis acuta, Dinophysis acuminata and M. rubrum to study the motility loss...... and aggregate formation of the ciliates and the feeding behaviour of Dinophysis were carried out. In cultures of either Dinophysis species, the ciliates became entrapped in the mucus, which led to the formation of immobile aggregates of M. rubrum and subsequent cell lysis. The proportion of entrapped ciliates...... was influenced by the concentration of Dinophysis and the ratio of predator and prey in the cultures. At high cell concentrations of prey (136 cells mL−1) and predator (100 cells mL−1), a maximum of 17% of M. rubrum cells became immobile and went through cell lysis. Ciliates were observed trapped in the mucus...

  4. Droplet Microfluidics for Compartmentalized Cell Lysis and Extension of DNA from Single-Cells

    Science.gov (United States)

    Zimny, Philip; Juncker, David; Reisner, Walter

    Current single cell DNA analysis methods suffer from (i) bias introduced by the need for molecular amplification and (ii) limited ability to sequence repetitive elements, resulting in (iii) an inability to obtain information regarding long range genomic features. Recent efforts to circumvent these limitations rely on techniques for sensing single molecules of DNA extracted from single-cells. Here we demonstrate a droplet microfluidic approach for encapsulation and biochemical processing of single-cells inside alginate microparticles. In our approach, single-cells are first packaged inside the alginate microparticles followed by cell lysis, DNA purification, and labeling steps performed off-chip inside this microparticle system. The alginate microparticles are then introduced inside a micro/nanofluidic system where the alginate is broken down via a chelating buffer, releasing long DNA molecules which are then extended inside nanofluidic channels for analysis via standard mapping protocols.

  5. Cell lysis and superoxide dismutase activities of highly radioresistant bacteria

    International Nuclear Information System (INIS)

    Yoshinaka, Taeko; Yano, Keiji; Yamaguchi, Hikoyuki

    1976-01-01

    The highly radioresistant bacterium, Arthrobacter radiotolerans, has been isolated from the radioactive hot spring of Misasa, and it does not sporulate, it is Gram-positive, and its color is pink to red. This bacterium shows the highest resistance to gamma-ray among Gram-positive resistants, but the lytic enzyme capable of lysing the cells of strong radioresistants and the surface structure of the cells are little known except those about Micrococcus radiodurans. The cells of the M. radiodurans can be lysed by Achramobacter lyticus enzyme, and electron microscopic observation and chemical analysis revealed the mutilayered surface structure of the cells consisting of an inner membrane, a mucopeptide wall layer and a very outer layer. The superoxide dismutase (SOD) activity of aerobic and anaerobic bacteria was studied, and the relatively high SOD activity of the M. radiodurans was found. The SOD function acts against the threat posed by the reactive superoxide radical being generated biologically, photochemically and radiochemically in the presence of molecular oxygen. In this paper, it is reported that the lytic enzyme No.2 obtained from Cytophaga sp., containing N-acetyl-muramyl-L-alanine amidase, peptidase and endopeptidase, and showing broad lytic spectra, was able to lyse the cells of A. radiotolerans and four radioresistant micrococci, and the radioresistant bacteria showed relatively high SOD activity except M. sp. 248. It is well known that superoxide anions are generated by aerobic irradiation, and are toxic to microbial cells. (Kako, I.)

  6. Cell lysis and superoxide dismutase activities of highly radioresistant bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Yoshinaka, T; Yano, K; Yamaguchi, H [Tokyo Univ. (Japan). Faculty of Agriculture

    1976-01-01

    The highly radioresistant bacterium, Arthrobacter radiotolerans, has been isolated from the radioactive hot spring of Misasa, and it does not sporulate, it is Gram-positive, and its color is pink to red. This bacterium shows the highest resistance to gamma-ray among Gram-positive resistants, but the lytic enzyme capable of lysing the cells of strong radioresistants and the surface structure of the cells are little known except those about Micrococcus radiodurans. The cells of the M. radiodurans can be lysed by Achramobacter lyticus enzyme, and electron microscopic observation and chemical analysis revealed the mutilayered surface structure of the cells consisting of an inner membrane, a mucopeptide wall layer and a very outer layer. The superoxide dismutase (SOD) activity of aerobic and anaerobic bacteria was studied, and the relatively high SOD activity of the M. radiodurans was found. The SOD function acts against the threat posed by the reactive superoxide radical being generated biologically, photochemically and radiochemically in the presence of molecular oxygen. In this paper, it is reported that the lytic enzyme No.2 obtained from Cytophaga sp., containing N-acetyl-muramyl-L-alanine amidase, peptidase and endopeptidase, and showing broad lytic spectra, was able to lyse the cells of A. radiotolerans and four radioresistant micrococci, and the radioresistant bacteria showedrelatively high SOD activity except M. sp. 248. It is well known that superoxide anions are generated by aerobic irradiation, and are toxic to microbial cells.

  7. Fractalkine expression induces endothelial progenitor cell lysis by natural killer cells.

    Directory of Open Access Journals (Sweden)

    Dilyana Todorova

    Full Text Available BACKGROUND: Circulating CD34(+ cells, a population that includes endothelial progenitors, participate in the maintenance of endothelial integrity. Better understanding of the mechanisms that regulate their survival is crucial to improve their regenerative activity in cardiovascular and renal diseases. Chemokine-receptor cross talk is critical in regulating cell homeostasis. We hypothesized that cell surface expression of the chemokine fractalkine (FKN could target progenitor cell injury by Natural Killer (NK cells, thereby limiting their availability for vascular repair. METHODOLOGY/PRINCIPAL FINDINGS: We show that CD34(+-derived Endothelial Colony Forming Cells (ECFC can express FKN in response to TNF-α and IFN-γ inflammatory cytokines and that FKN expression by ECFC stimulates NK cell adhesion, NK cell-mediated ECFC lysis and microparticles release in vitro. The specific involvement of membrane FKN in these processes was demonstrated using FKN-transfected ECFC and anti-FKN blocking antibody. FKN expression was also evidenced on circulating CD34(+ progenitor cells and was detected at higher frequency in kidney transplant recipients, when compared to healthy controls. The proportion of CD34(+ cells expressing FKN was identified as an independent variable inversely correlated to CD34(+ progenitor cell count. We further showed that treatment of CD34(+ circulating cells isolated from adult blood donors with transplant serum or TNF-α/IFN-γ can induce FKN expression. CONCLUSIONS: Our data highlights a novel mechanism by which FKN expression on CD34(+ progenitor cells may target their NK cell mediated killing and participate to their immune depletion in transplant recipients. Considering the numerous diseased contexts shown to promote FKN expression, our data identify FKN as a hallmark of altered progenitor cell homeostasis with potential implications in better evaluation of vascular repair in patients.

  8. Normal human serum (HS) prevents oxidant-induced lysis of cultured endothelial cells (ECs)

    International Nuclear Information System (INIS)

    Callahan, K.S.; Harlan, J.M.

    1986-01-01

    Most studies demonstrating oxidant lysis of cultured ECs are performed in serum-free media or media containing low concentrations of bovine serum. The authors found that HS protects human and bovine ECs from lysis caused by reagent H 2 O 2 or glucose/glucose oxidase (GO)-generated H 2 O 2 . EC injury was assessed by 51 Cr release, cell detachment, or trypan blue dye exclusion. Protective HS activity was dose-dependent with concentrations greater than or equal to 25% preventing lethal injury. Cytotoxicity at 24 hrs, induced by 20 mU/ml GO, was 90.1 +/- 5.2% without HS vs 1.7 +/- 4.6% with 25% HS present (20 exp). Similar protection was observed with heparinized plasma. Of note, comparable concentrations of bovine serum were devoid of protective activity. Addition of fatty acid-free albumin to the media was also without protective effect. Preliminary characterization showed HS activity was stable to 60 0 C for 30 min, non-dialyzable at 25,000 MW cutoff, and retained in delipidated serum. The HS protection was not merely due to scavenging of exogenous H 2 O 2 as A23187-induced EC lysis was also prevented by HS. Protective activity was not reproduced by purified cerruloplasmin or transferrin. In conclusion, unidentified factor(s) present in HS protect cultured ECs from oxidant-induced lysis. Since endothelium is normally exposed to 100% plasma, the authors suggest that in vitro studies of oxidant-mediated injury be performed in the presence of HS. Factor(s) in HS may play an important role in modulating oxidant-induced vascular injury in vivo

  9. Resistance of some leukemic blasts to lysis by lymphokine activated killer (LAK) cells

    Energy Technology Data Exchange (ETDEWEB)

    Panayotides, P; Sjoegren, A -M; Reizenstein, P; Porwit, A. Immunopathology Lab., Dept. of Pathology, Karolinska Hospital, Stockholm; Wasserman, J

    1988-01-01

    Peripheral blood mononuclear cells (PBMC) from healthy donors and AML patients in remission were stimulated with phytohemagglutinin (PHA) and recombinant interleukin-2 (IL-2). These stimulated cells (lymphokine activated killer (LAK) cells) showed increased DNA synthesis as measured by /sup 3/H-Thymidine uptake. A synergistic effect of PHA and IL-2 was found. LAK cells' ability to kill acute myeloid leukemia (AML) blasts was investigated by the /sup 51/Cr release assay. LAK cells showed a cytotoxicity (over 10% specific /sup 51/Cr release) against 9/12 leukemic blasts, even at effector/target (E/T) ratios as low as 5:1. However, on average only 22.2% (SD 11.8) and 36.5% (SD 12.5) /sup 51/Cr release were obtained in 4- and 18-hour cytotoxicity assays, respectively, at an E/T ratio of 20:1. Leukemic blasts in 3/12 AML cases and normal PBMC were entirely resistant to lysis, even at an E/T ratio of 80:1. Susceptibility to lysis was not correlated to peanut-agglutinin receptor expression. LAK cells were more cytotoxic towards the K-562 cell line (natural killer activity) than unstimulated PBMC.

  10. Capacity of tumor necrosis factor to augment lymphocyte-mediated tumor cell lysis of malignant mesothelioma

    International Nuclear Information System (INIS)

    Bowman, R.V.; Manning, L.S.; Davis, M.R.; Robinson, B.W.

    1991-01-01

    Recombinant human tumor necrosis factor (rHuTNF) was evaluated both for direct anti-tumor action against human malignant mesothelioma and for its capacity to augment the generation and lytic phases of lymphocyte-mediated cytotoxicity against this tumor. rHuTNF was directly toxic by MTT assay to one of two mesothelioma cell lines evaluated, but had no effect on susceptibility to subsequent lymphocyte-mediated lysis of either line. TNF alone was incapable of generating anti-mesothelioma lymphokine-activated killer cell (LAK) activity. Furthermore, it did not augment the degree or LAK activity produced by submaximal interleukin-2 (IL-2) concentrations nor did it augment lysis of mesothelioma cells by natural killer (NK) or LAK effector cells during the 4-hr 51chromium release cytolytic reaction. The studies also suggest that mesothelioma targets are less responsive to TNF plus submaximal IL-2 concentrations than the standard LAK sensitive target Daudi, raising the possibility that intermediate LAK sensitive tumors such as mesothelioma may require separate and specific evaluation in immunomodulation studies. This in vitro study indicates that use of low-dose rHuTNF and IL-2 is unlikely to be an effective substitute for high-dose IL-2 in generation and maintenance of LAK activity in adoptive immunotherapy for mesothelioma

  11. Hyphal growth of phagocytosed Fusarium oxysporum causes cell lysis and death of murine macrophages.

    Directory of Open Access Journals (Sweden)

    Katja Schäfer

    Full Text Available Fusarium oxysporum is an important plant pathogen and an opportunistic pathogen of humans. Here we investigated phagocytosis of F. oxysporum by J774.1 murine cell line macrophages using live cell video microscopy. Macrophages avidly migrated towards F. oxysporum germlings and were rapidly engulfed after cell-cell contact was established. F. oxysporum germlings continued hyphal growth after engulfment by macrophages, leading to associated macrophage lysis and escape. Macrophage killing depended on the multiplicity of infection. After engulfment, F. oxysporum inhibited macrophages from completing mitosis, resulting in large daughter cells fused together by means of a F. oxysporum hypha. These results shed new light on the initial stages of Fusarium infection and the innate immune response of the mammalian host.

  12. Hyphal growth of phagocytosed Fusarium oxysporum causes cell lysis and death of murine macrophages.

    Science.gov (United States)

    Schäfer, Katja; Bain, Judith M; Di Pietro, Antonio; Gow, Neil A R; Erwig, Lars P

    2014-01-01

    Fusarium oxysporum is an important plant pathogen and an opportunistic pathogen of humans. Here we investigated phagocytosis of F. oxysporum by J774.1 murine cell line macrophages using live cell video microscopy. Macrophages avidly migrated towards F. oxysporum germlings and were rapidly engulfed after cell-cell contact was established. F. oxysporum germlings continued hyphal growth after engulfment by macrophages, leading to associated macrophage lysis and escape. Macrophage killing depended on the multiplicity of infection. After engulfment, F. oxysporum inhibited macrophages from completing mitosis, resulting in large daughter cells fused together by means of a F. oxysporum hypha. These results shed new light on the initial stages of Fusarium infection and the innate immune response of the mammalian host.

  13. Impaired respiration elicits SrrAB-dependent programmed cell lysis and biofilm formation in Staphylococcus aureus

    Science.gov (United States)

    Mashruwala, Ameya A; van de Guchte, Adriana; Boyd, Jeffrey M

    2017-01-01

    Biofilms are communities of microorganisms attached to a surface or each other. Biofilm-associated cells are the etiologic agents of recurrent Staphylococcus aureus infections. Infected human tissues are hypoxic or anoxic. S. aureus increases biofilm formation in response to hypoxia, but how this occurs is unknown. In the current study we report that oxygen influences biofilm formation in its capacity as a terminal electron acceptor for cellular respiration. Genetic, physiological, or chemical inhibition of respiratory processes elicited increased biofilm formation. Impaired respiration led to increased cell lysis via divergent regulation of two processes: increased expression of the AtlA murein hydrolase and decreased expression of wall-teichoic acids. The AltA-dependent release of cytosolic DNA contributed to increased biofilm formation. Further, cell lysis and biofilm formation were governed by the SrrAB two-component regulatory system. Data presented support a model wherein SrrAB-dependent biofilm formation occurs in response to the accumulation of reduced menaquinone. DOI: http://dx.doi.org/10.7554/eLife.23845.001 PMID:28221135

  14. Investigation of an optimal cell lysis method for the study of the zinc metalloproteome of Histoplasma capsulatum.

    Science.gov (United States)

    Donnell, Anna M; Lewis, Stephanie; Abraham, Sami; Subramanian, Kavitha; Figueroa, Julio Landero; Deepe, George S; Vonderheide, Anne P

    2017-10-01

    This work sought to assess optimal extraction conditions in the study of the metalloproteome of the dimorphic fungus Histoplasma capsulatum. One of the body's responses to H. capsulatum infection is sequestration of zinc within host macrophage (MØ), as reported by Vignesh et al. (Immunity 39:697-710, 2013) and Vignesh et al. (PLOS Pathog 9:E1003815, 2013). Thus, metalloproteins containing zinc were of greatest interest as it plays a critical role in survival of the fungus. One challenge in metalloproteomics is the preservation of the native structure of proteins to retain non-covalently bound metals. Many of the conventional cell lysis, separation, and identification techniques in proteomics are carried out under conditions that could lead to protein denaturation. Various cell lysis techniques were investigated in an effort to both maintain the metalloproteins during lysis and subsequent analysis while, at the same time, serving to be strong enough to break the cell wall, allowing access to cytosolic metalloproteins. The addition of 1% Triton x-100, a non-ionic detergent, to the lysis buffer was also studied. Seven lysis methods were considered and these included: Glass Homogenizer (H), Bead Beater (BB), Sonication Probe (SP), Vortex with 1% Triton x-100 (V, T), Vortex with no Triton x-100 (V, NT), Sonication Bath, Vortex, and 1% Triton x-100 (SB, V, T) and Sonication Bath, Vortex, and no Triton x-100 (SB, V, NT). A Qubit® Assay was used to compare total protein concentration and inductively coupled plasma-mass spectrometry (ICP-MS) was utilized for total metal analysis of cell lysates. Size exclusion chromatography coupled to ICP-MS (SEC-HPLC-ICP-MS) was used for separation of the metalloproteins in the cell lysate and the concentration of Zn over a wide molecular weight range was examined. Additional factors such as potential contamination sources were also considered. A cell lysis method involving vortexing H. capsulatum yeast cells with 500 μm glass beads

  15. Investigation of chemical vapour deposition diamond detectors by X-ray micro-beam induced current and X-ray micro-beam induced luminescence techniques

    International Nuclear Information System (INIS)

    Olivero, P.; Manfredotti, C.; Vittone, E.; Fizzotti, F.; Paolini, C.; Lo Giudice, A.; Barrett, R.; Tucoulou, R.

    2004-01-01

    Tracking detectors have become an important ingredient in high-energy physics experiments. In order to survive the harsh detection environment of the large hadron collider (LHC), trackers need to have special properties. They must be radiation hard, provide fast collection of charge, be as thin as possible and remove heat from readout electronics. The unique properties of diamond allow it to fulfill these requirements. In this work we present an investigation of the charge transport and luminescence properties of 'detector grade' artificial chemical vapour deposition (CVD) diamond devices developed within the CERN RD42 collaboration, performed by means of X-ray micro-beam induced current collection (XBICC) and X-ray micro-beam induced luminescence (XBIL) techniques. XBICC technique allows quantitative estimates of the transport parameters of the material to be evaluated and mapped with micrometric spatial resolution. In particular, the high resolution and sensitivity of the technique has allowed a quantitative study of the inhomogeneity of the charge transport parameter defined as the product of mobility and lifetime for both electron and holes. XBIL represents a technique complementary to ion beam induced luminescence (IBIL), which has already been used by our group, since X-ray energy loss profile in the material is different from that of MeV ions. X-ray induced luminescence maps have been performed simultaneously with induced photocurrent maps, to correlate charge transport and induced luminescence properties of diamond. Simultaneous XBICC and XBIL maps exhibit features of partial complementarity that have been interpreted on the basis of considerations on radiative and non-radiative recombination processes which compete with charge transport efficiency

  16. Continuous nucleus extraction by optically-induced cell lysis on a batch-type microfluidic platform.

    Science.gov (United States)

    Huang, Shih-Hsuan; Hung, Lien-Yu; Lee, Gwo-Bin

    2016-04-21

    The extraction of a cell's nucleus is an essential technique required for a number of procedures, such as disease diagnosis, genetic replication, and animal cloning. However, existing nucleus extraction techniques are relatively inefficient and labor-intensive. Therefore, this study presents an innovative, microfluidics-based approach featuring optically-induced cell lysis (OICL) for nucleus extraction and collection in an automatic format. In comparison to previous micro-devices designed for nucleus extraction, the new OICL device designed herein is superior in terms of flexibility, selectivity, and efficiency. To facilitate this OICL module for continuous nucleus extraction, we further integrated an optically-induced dielectrophoresis (ODEP) module with the OICL device within the microfluidic chip. This on-chip integration circumvents the need for highly trained personnel and expensive, cumbersome equipment. Specifically, this microfluidic system automates four steps by 1) automatically focusing and transporting cells, 2) releasing the nuclei on the OICL module, 3) isolating the nuclei on the ODEP module, and 4) collecting the nuclei in the outlet chamber. The efficiency of cell membrane lysis and the ODEP nucleus separation was measured to be 78.04 ± 5.70% and 80.90 ± 5.98%, respectively, leading to an overall nucleus extraction efficiency of 58.21 ± 2.21%. These results demonstrate that this microfluidics-based system can successfully perform nucleus extraction, and the integrated platform is therefore promising in cell fusion technology with the goal of achieving genetic replication, or even animal cloning, in the near future.

  17. All-in-one nanowire-decorated multifunctional membrane for rapid cell lysis and direct DNA isolation.

    KAUST Repository

    So, Hongyun

    2014-11-24

    This paper describes a handheld device that uses an all-in-one membrane for continuous mechanical cell lysis and rapid DNA isolation without the assistance of power sources, lysis reagents, and routine centrifugation. This nanowire-decorated multifunctional membrane was fabricated to isolate DNA by selective adsorption to silica surface immediately after disruption of nucleus membranes by ultrasharp tips of nanowires for a rapid cell lysis, and it can be directly assembled with commercial syringe filter holders. The membrane was fabricated by photoelectrochemical etching to create microchannel arrays followed by hydrothermal synthesis of nanowires and deposition of silica. The proposed membrane successfully purifies high-quality DNA within 5 min, whereas a commercial purification kit needs more than an hour.

  18. All-in-one nanowire-decorated multifunctional membrane for rapid cell lysis and direct DNA isolation.

    KAUST Repository

    So, Hongyun; Lee, Kunwoo; Murthy, Niren; Pisano, Albert P

    2014-01-01

    This paper describes a handheld device that uses an all-in-one membrane for continuous mechanical cell lysis and rapid DNA isolation without the assistance of power sources, lysis reagents, and routine centrifugation. This nanowire-decorated multifunctional membrane was fabricated to isolate DNA by selective adsorption to silica surface immediately after disruption of nucleus membranes by ultrasharp tips of nanowires for a rapid cell lysis, and it can be directly assembled with commercial syringe filter holders. The membrane was fabricated by photoelectrochemical etching to create microchannel arrays followed by hydrothermal synthesis of nanowires and deposition of silica. The proposed membrane successfully purifies high-quality DNA within 5 min, whereas a commercial purification kit needs more than an hour.

  19. Stabilizing additives added during cell lysis aid in the solubilization of recombinant proteins.

    Directory of Open Access Journals (Sweden)

    David J Leibly

    Full Text Available Insoluble recombinant proteins are a major issue for both structural genomics and enzymology research. Greater than 30% of recombinant proteins expressed in Escherichia coli (E. coli appear to be insoluble. The prevailing view is that insolubly expressed proteins cannot be easily solubilized, and are usually sequestered into inclusion bodies. However, we hypothesize that small molecules added during the cell lysis stage can yield soluble protein from insoluble protein previously screened without additives or ligands. We present a novel screening method that utilized 144 additive conditions to increase the solubility of recombinant proteins expressed in E. coli. These selected additives are natural ligands, detergents, salts, buffers, and chemicals that have been shown to increase the stability of proteins in vivo. We present the methods used for this additive solubility screen and detailed results for 41 potential drug target recombinant proteins from infectious organisms. Increased solubility was observed for 80% of the recombinant proteins during the primary and secondary screening of lysis with the additives; that is 33 of 41 target proteins had increased solubility compared with no additive controls. Eleven additives (trehalose, glycine betaine, mannitol, L-Arginine, potassium citrate, CuCl(2, proline, xylitol, NDSB 201, CTAB and K(2PO(4 solubilized more than one of the 41 proteins; these additives can be easily screened to increase protein solubility. Large-scale purifications were attempted for 15 of the proteins using the additives identified and eight (40% were prepared for crystallization trials during the first purification attempt. Thus, this protocol allowed us to recover about a third of seemingly insoluble proteins for crystallography and structure determination. If recombinant proteins are required in smaller quantities or less purity, the final success rate may be even higher.

  20. Features of target cell lysis by class I and class II MHC restricted cytolytic T lymphocytes

    International Nuclear Information System (INIS)

    Maimone, M.M.; Morrison, L.A.; Braciale, V.L.; Braciale, T.J.

    1986-01-01

    The lytic activity of influenza virus-specific muvine cytolytic T lymphocyte (CTL) clones that are restricted by either H-2K/D (class I) or H-2I (class II) major histocompatibility (MHC) locus products was compared on an influenza virus-infected target cell expressing both K/D and I locus products. With the use of two in vitro measurements of cytotoxicity, conventional 51 Cr release, and detergent-releasable radiolabeled DNA (as a measure of nuclear disintegration in the early post-lethal hit period), the authors found no difference between class I and class II MHC-restricted CTL in the kinetics of target cell destruction. In addition, class II MHC-restricted antiviral CTL failed to show any lysis of radiolabeled bystander cells. Killing of labeled specific targets by these class II MHC-restricted CTL was also efficiently inhibited by unlabeled specific competitor cells in a cold target inhibition assay. In sum, these data suggest that class I and class II MHC-restricted CTL mediate target cell destruction by an essentially similar direct mechanism

  1. Characterization of cell lysis in Pseudomonas putida induced upon expression of heterologous killing genes

    DEFF Research Database (Denmark)

    Ronchel, M.C.; Molina, L.; Witte, A.

    1998-01-01

    Active biological containment systems are based on the controlled expression of killing genes. These systems are of interest for the Pseudomonadaceae because of the potential applications of these microbes as bioremediation agents and biopesticides, The physiological effects that lead to cell dea...... protein was the killing agent. In both cases, cell death occurred as a result of impaired respiration, altered membrane permeability, and the release of some cytoplasmic contents to the extracellular medium.......Active biological containment systems are based on the controlled expression of killing genes. These systems are of interest for the Pseudomonadaceae because of the potential applications of these microbes as bioremediation agents and biopesticides, The physiological effects that lead to cell death......, respectively. Expression of the killing genes is controlled by the LacI protein, whose expression is initiated from the XylS-dependent Pm promoter. Under induced conditions, killing of P. putida CMC12 cells mediated by phi X174 lysis protein E was faster than that observed for P. putida CMC4, for which the Gef...

  2. Study of a novel cell lysis method with titanium dioxide for Lab-on-a-Chip devices.

    Science.gov (United States)

    Wan, Weijie; Yeow, John T W

    2011-06-01

    In this paper, a novel method is proposed and demonstrated to be able to lyse gram-negative (E. coli) bacteria cells for Lab-on-a-Chip applications. The proposed method incorporates using titanium dioxide particles as photocatalysts and a miniaturized UV LED array as an excitation light source to perform cell lysis on microchips. The experimental result demonstrates the feasibility of the proposed prototype device. The working device suggests an inexpensive, easy to be fabricated and effective way for microchip cell lysis. The miniaturized UV LED array and the microchip with a reaction chamber can be easily integrated with other functional components to form a customized whole Lab-on-a-Chip system.

  3. Demonstration of NK cell-mediated lysis of varicella-zoster virus (VZV)-infected cells: characterization of the effector cells

    Energy Technology Data Exchange (ETDEWEB)

    Tilden, A.B.; Cauda, R.; Grossi, C.E.; Balch, C.M.; Lakeman, A.D.; Whitley, R.J.

    1986-06-01

    Infection with varicella-zoster virus (VZV) rendered RAJI cells more susceptible to lysis by non-adherent blood lymphocytes. At an effector to target ratio of 80:1 the mean percentage of /sup 51/Cr release of VZV-infected RAJI cells was 41 +/- 12%, whereas that of uninfected RAJI cells was 15 +/- 6%. The increased susceptibility to lysis was associated with increased effector to target conjugate formation in immunofluorescence binding assays. The effector cells cytotoxic for VZV-infected RAJI cells were predominantly Leu-11a/sup +/ Leu-4/sup -/ granular lymphocytes as demonstrated by fluorescence-activated cell sorting. The effector cell active against VZV-infected RAJI cells appeared similar to those active against herpes simplex virus (HSV)-infected cells, because in cold target competition experiments the lysis of /sup 51/Cr-labeled VZV-infected RAJI cells was efficiently inhibited by either unlabeled VZV-infected RAJI cells (mean 71% inhibition, 2:1 ratio unlabeled to labeled target) or HSV-infected RAJI cells (mean 69% inhibition) but not by uninfected RAJI cells (mean 10% inhibition). In contrast, competition experiments revealed donor heterogeneity in the overlap between effector cells for VZV- or HSV-infected RAJI vs K-562 cells.

  4. Concerning the role of cell lysis-cryptic growth in anaerobic side-stream reactors: the single-cell analysis of viable, dead and lysed bacteria.

    Science.gov (United States)

    Foladori, P; Velho, V F; Costa, R H R; Bruni, L; Quaranta, A; Andreottola, G

    2015-05-01

    In the Anaerobic Side-Stream Reactor (ASSR), part of the return sludge undergoes alternating aerobic and anaerobic conditions with the aim of reducing sludge production. In this paper, viability, enzymatic activity, death and lysis of bacterial cells exposed to aerobic and anaerobic conditions for 16 d were investigated at single-cell level by flow cytometry, with the objective of contributing to the understanding of the mechanisms of sludge reduction in the ASSR systems. Results indicated that total and viable bacteria did not decrease during the anaerobic phase, indicating that anaerobiosis at ambient temperature does not produce a significant cell lysis. Bacteria decay and lysis occurred principally under aerobic conditions. The aerobic decay rate of total bacteria (bTB) was considered as the rate of generation of lysed bacteria. Values of bTB of 0.07-0.11 d(-1) were measured in anaerobic + aerobic sequence. The enzymatic activity was not particularly affected by the transition from anaerobiosis to aerobiosis. Large solubilisation of COD and NH4(+) was observed only under anaerobic conditions, as a consequence of hydrolysis of organic matter, but not due to cell lysis. The observations supported the proposal of two independent mechanisms contributing equally to sludge reduction: (1) under anaerobic conditions: sludge hydrolysis of non-bacterial material, (2) under aerobic conditions: bacterial cell lysis and oxidation of released biodegradable compounds. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Enhanced lysis of herpes simplex virus type 1-infected mouse cell lines by NC and NK effectors

    Energy Technology Data Exchange (ETDEWEB)

    Colmenares, C.; Lopez, C.

    1986-05-01

    Spontaneously cytotoxic murine lymphocytes lysed certain cell types infected by herpes simplex virus type 1 (HSV-1) better than uninfected cells. Although HSV-1 adsorbed to the surface of all the target cells, those in which the virus replicated more efficiently were lysed to a greater extent. As targets, the authors used cell lines that, when uninfected, were spontaneously lysed by NK cells (YAC-1) or by NC cells (WEHI-164). They also used a fibroblastoid cell line (M50) and a monocytic tumor line (PU51R), which were not spontaneously killed. NK cells lysed HSV-1-infected YAC cells better than uninfected cells, and an NC-like activity selectively lysed HSV-1-infected WEHI cells. These findings were consistent with the results of experiments performed to define the role of interferon in induction of virus-augmented cytolysis. Increased lysis of YAC-HSV and PU51R-HSV was entirely due to interferon activation and was completely abolished by performing the /sup 51/Cr-release assay in the presence of anti-interferon serum. The data show that HSV-1 infection of NK/NC targets induces increased cytotoxity, but the effector cell responsible for lysis is determined by the uninfected target, or by an interaction between the virus and target cell, rather than by a viral determinant alone.

  6. Chitosan as coagulant on cyanobacteria in lake restoration management may cause rapid cell lysis.

    Science.gov (United States)

    Mucci, Maíra; Noyma, Natalia Pessoa; de Magalhães, Leonardo; Miranda, Marcela; van Oosterhout, Frank; Guedes, Iamê Alves; Huszar, Vera L M; Marinho, Marcelo Manzi; Lürling, Miquel

    2017-07-01

    Combining coagulant and ballast to remove cyanobacteria from the water column is a promising restoration technique to mitigate cyanobacterial nuisance in surface waters. The organic, biodegradable polymer chitosan has been promoted as a coagulant and is viewed as non-toxic. In this study, we show that chitosan may rapidly compromise membrane integrity and kill certain cyanobacteria leading to release of cell contents in the water. A strain of Cylindrospermopsis raciborskii and one strain of Planktothrix agardhii were most sensitive. A 1.3 h exposure to a low dose of 0.5 mg l -1 chitosan already almost completely killed these cultures resulting in release of cell contents. After 24 h, reductions in PSII efficiencies of all cyanobacteria tested were observed. EC50 values varied from around 0.5 mg l -1 chitosan for the two sensitive strains, via about 5 mg l -1 chitosan for an Aphanizomenon flos-aquae strain, a toxic P. agardhii strain and two Anabaena cylindrica cultures, to more than 8 mg l -1 chitosan for a Microcystis aeruginosa strain and another A. flos-aquae strain. Differences in sensitivity to chitosan might be related to polymeric substances that surround cyanobacteria. Rapid lysis of toxic strains is likely and when chitosan flocking and sinking of cyanobacteria is considered in lake restoration, flocculation efficacy studies should be complemented with investigation on the effects of chitosan on the cyanobacteria assemblage being targeted. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. Artificial intelligence versus statistical modeling and optimization of continuous bead milling process for bacterial cell lysis

    Directory of Open Access Journals (Sweden)

    Shafiul Haque

    2016-11-01

    Full Text Available AbstractFor a commercially viable recombinant intracellular protein production process, efficient cell lysis and protein release is a major bottleneck. The recovery of recombinant protein, cholesterol oxidase (COD was studied in a continuous bead milling process. A full factorial Response Surface Model (RSM design was employed and compared to Artificial Neural Networks coupled with Genetic Algorithm (ANN-GA. Significant process variables, cell slurry feed rate (A, bead load (B, cell load (C and run time (D, were investigated and optimized for maximizing COD recovery. RSM predicted an optimum of feed rate of 310.73 mL/h, bead loading of 79.9% (v/v, cell loading OD600 nm of 74, and run time of 29.9 min with a recovery of ~3.2 g/L. ANN coupled with GA predicted a maximum COD recovery of ~3.5 g/L at an optimum feed rate (mL/h: 258.08, bead loading (%, v/v: 80%, cell loading (OD600 nm: 73.99, and run time of 32 min. An overall 3.7-fold increase in productivity is obtained when compared to a batch process. Optimization and comparison of statistical vs. artificial intelligence techniques in continuous bead milling process has been attempted for the very first time in our study. We were able to successfully represent the complex non-linear multivariable dependence of enzyme recovery on bead milling parameters. The quadratic second order response functions are not flexible enough to represent such complex non-linear dependence. ANN being a summation function of multiple layers are capable to represent complex non-linear dependence of variables in this case; enzyme recovery as a function of bead milling parameters. Since GA can even optimize discontinuous functions present study cites a perfect example of using machine learning (ANN in combination with evolutionary optimization (GA for representing undefined biological functions which is the case for common industrial processes involving biological moieties.

  8. Sub-apoptotic dosages of pro-oxidant vitamin cocktails sensitize human melanoma cells to NK cell lysis.

    Science.gov (United States)

    Tremante, Elisa; Santarelli, Lory; Lo Monaco, Elisa; Sampaoli, Camilla; Ingegnere, Tiziano; Guerrieri, Roberto; Tomasetti, Marco; Giacomini, Patrizio

    2015-10-13

    Alpha-tocopheryl succinate (αTOS), vitamin K3 (VK3) and vitamin C (ascorbic acid, AA) were previously shown to synergistically promote different death pathways in carcinoma cells, depending on their concentrations and combinations. Similar effects were observed herein in melanoma cells, although αTOS behaved as an antagonist. Interestingly, suboptimal cell death-inducing concentrations (1.5 μM αTOS/20 μM AA/0.2 μM VK3) effectively up-regulated activating Natural Killer (NK) cell ligands, including MICA (the stress-signaling ligand of the NKG2D receptor), and/or the ligands of at least one of the natural cytotoxicity receptors (NKp30, NKp44 and NKp46) in 5/6 melanoma cell lines. Only an isolated MICA down-regulation was seen. HLA class I, HLA class II, ULBP1, ULBP2, ULBP3, Nectin-2, and PVR displayed little, if any, change in expression. Ligand up-regulation resulted in improved lysis by polyclonal NK cells armed with the corresponding activating receptors. These results provide the first evidence for concerted induction of cell death by cell-autonomous and extrinsic (immune) mechanisms. Alarming the immune system much below the cell damage threshold may have evolved as a sensitive readout of neoplastic transformation and oxidative stress. Cocktails of vitamin analogues at slightly supra-physiological dosages may find application as mild complements of melanoma treatment, and in chemoprevention.

  9. Mingled Mortality: the Interplay Between Protist Grazing and Viral Lysis on Emiliania huxleyi Cell Fate

    Science.gov (United States)

    Harvey, E.; Bidle, K. D.; Johnson, M. D.

    2016-02-01

    The coccolithophore, Emiliania huxleyi plays a prominent role in global carbon cycling, as their calcite coccoliths account for a third of all oceanic calcite production. Mortality due to grazing by microzooplankton is the largest contributor to phytoplankton loss in the marine environment. However, viral infection of E. huxleyi is now thought to be as important as grazing pressure in contributing to its mortality. To understand the influence of viral infection on grazing dynamics, we examined the response of the dinoflagellate predator, Oxyrrhis marina to E. huxleyi infected with four different strains of the E. huxleyi virus (EhV). Grazing rate was significantly slower on E. huxleyi cultures that had been infected for 48 h compared to an uninfected control and this reduction in grazing rate was dependent on the strain identity of infecting EhVs. Additional experimentation indicated that grazing was the primary source of E. huxleyi loss ( 78-98%) during the first 24 h of exposure to both predator and virus. However, as viral infection progressed into the late lytic phase (48 h hour post infection), the relative contribution of grazing to total E. huxleyi mortality decreased ( 5-60%). These results suggest that mortality is partitioned along a gradient between predator-based consumption and virus-induced cell lysis, dependent on the timing of infection. Deciphering the relative importance and interactive nature of these alga-predator-viral interactions will help to elucidate the mechanisms that drive bulk measurements of phytoplankton loss, a necessary understanding to interpret and predict phytoplankton population dynamics and associated biogeochemical cycling.

  10. Organic and Inorganic Nitrogen Impact Chlorella variabilis Productivity and Host Quality for Viral Production and Cell Lysis.

    Science.gov (United States)

    Cheng, Yu-Shen; Labavitch, John; VanderGheynst, Jean S

    2015-05-01

    Microalgae have been proposed as a potential feedstock for biofuel production; however, cell disruption is usually required for collection and utilization of cytoplasmic polysaccharides and lipids. Virus infection might be one approach to disrupt the cell wall. The concentration of yeast extract and presence of KNO3 in algae cultivation media were investigated to observe their effects on Chlorella variabilis NC64A physiology and composition and the subsequent effect on production of Chlorella virus and disruption of infected cells. Cytoplasmic starch accumulation increased from 5% to approximately 35% of the total dry weight when yeast extract decreased from 1 to 0.25 g L(-1). When cells were cultured with the lowest nitrogen levels, the total polysaccharide accounted for more than 50% of the cell wall, which was 1.7 times higher than the content in cells cultured with the highest nitrogen levels. The C/N ratio of the algal biomass decreased by a factor of approximately 2 when yeast extract increased from 0.25 to 1 g L(-1). After virus infection, cells with a low C/N ratio produced a 7.6 times higher burst size than cells with a high C/N ratio, suggesting that the nitrogen content in C. variabilis has a large influence on viral production and cell lysis. The results have implications on management of nitrogen for both the synthesis of products from algae and product recovery via viral lysis.

  11. Very High Throughput Electrical Cell Lysis and Extraction of Intracellular Compounds Using 3D Carbon Electrodes in Lab-on-a-Chip Devices

    Directory of Open Access Journals (Sweden)

    Philippe Renaud

    2012-08-01

    Full Text Available Here we present an electrical lysis throughput of 600 microliters per minute at high cell density (108 yeast cells per ml with 90% efficiency, thus improving the current common throughput of one microliter per minute. We also demonstrate the extraction of intracellular luciferase from mammalian cells with efficiency comparable to off-chip bulk chemical lysis. The goal of this work is to develop a sample preparation module that can act as a stand-alone device or be integrated to other functions already demonstrated in miniaturized devices, including sorting and analysis, towards a true lab-on-a-chip.

  12. Lysis of cells infected with typhus group rickettsiae by a human cytotoxic T cell clone

    International Nuclear Information System (INIS)

    Carl, M.; Robbins, F.; Hartzman, R.J.; Dasch, G.A.

    1987-01-01

    Cytolytic human T cells clones generated in response to the intracellular bacterium Rickettsia typhi were characterized. Growing clones were tested for their ability to proliferate specifically in response to antigens derived from typhus group rickettsiae or to lyse targets infected with R. typhi or Rickettsia prowazekii, as measured by 51 Cr-release from target cells. Two clones were able to lyse targets infected with typhus group rickettsiae. One of these clones was more fully characterized because of its rapid growth characteristics. This cytolytic clone was capable of lysing an autologous infected target as well as a target matched for class I and II histocompatibility leukocyte antigens (HLA). It was not capable, however, of lysing either a target mismatched for both class I and II HLA or a target partially matched for class I HLA. In addition, the clone exhibited specificity in that it was able to lyse an autologous target infected with typhus group rickettsiae, but did not lyse an autologous target infected with an antigenically distinct rickettsial species, Rickettsia tsutsugamushi. These results demonstrate, for the first time, that cells infected with intracellular bacteria can be lysed by human cytotoxic T lymphocytes

  13. Proliferative and phenotypical characteristics of human adipose tissue-derived stem cells: comparison of Ficoll gradient centrifugation and red blood cell lysis buffer treatment purification methods.

    Science.gov (United States)

    Najar, Mehdi; Rodrigues, Robim M; Buyl, Karolien; Branson, Steven; Vanhaecke, Tamara; Lagneaux, Laurence; Rogiers, Vera; De Kock, Joery

    2014-09-01

    Adult human subcutaneous adipose tissue harbors a multipotent stem cell population, the so-called human adipose tissue-derived mesenchymal stromal cells (AT-MSCs). These cells are able to differentiate in vitro into various cell types and possess immunomodulatory features. Yet procedures to obtain AT-MSCs can vary significantly. The two most extensively used AT-MSC purification techniques are (i) density gradient centrifugation using Ficoll and (ii) red blood cell (RBC) lysis buffer treatment of the stromal vascular fraction. In the context of potential clinical cell therapy, the stem cell yield after purification and upon consecutive passages, as well as the purity of the obtained cell population, are of utmost importance. We investigated the expansion capacity and purity of AT-MSCs purified by both procedures immediately after isolation and upon consecutive passages. We also investigated possible purification-dependent differences in their expression of immune-inhibitory factors and cell adhesion molecules. We found that RBC lysis buffer treatment is a more robust and easier method to purify AT-MSCs than density gradient fractionation. However, the resulting AT-MSC-RBC population contains a significantly higher number of CD34(+) cells, particularly during the first passages after plating. From passage 4 onward, no significant differences could be observed between both populations with respect to the immunophenotype, expansion capacity and expression of immune inhibitory factors and cell adhesion molecules. Our data show that RBC lysis buffer treatment may be a good alternative to density fractionation, providing a faster, more robust and easier method to purify AT-MSCs with biologically preserved characteristics. Copyright © 2014 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

  14. Tumor lysis syndrome in children

    International Nuclear Information System (INIS)

    Suarez, Amaranto

    2004-01-01

    Tumor lysis syndrome is a metabolic emergency characterized by electrolyte alteration with or without acute renal failure. It occurs mainly in patients with malignant tumors that have a high growth fraction, or after cytotoxic therapy, as a result of the massive degradation of malignant cells and the release of high amounts of intracellular elements that exceed the capacity of renal excretion. The objective of the treatment is the prevention of nephropathy due to uric acid deposits, and the correction of metabolic acidosis and electrolyte alterations. This paper reviews the incidence, the physiopathology, and the treatment of tumor lysis syndrome in children

  15. Evaluation of cell lysis procedures and use of a micro fluidic system for an automated DNA-based cell identification in interplanetary missions

    Science.gov (United States)

    Hall, J. A.; Felnagle, E.; Fries, M.; Spearing, S.; Monaco, L.; Steele, A.

    2006-12-01

    A Modular Assay System for Solar System Exploration (MASSE) is being developed to include sample handling, pre-treatment, separation and analysis of biological target compounds by both DNA and protein microarrays. To better design sensitive and accurate initial upstream sample handling of the MASSE instrument, experiments investigating the sensitivity and potential extraction bias of commercially available DNA extraction kits between classes of environmentally relevant prokaryotes such as gram-negative bacteria ( Escherichia coli), gram-positive bacteria ( Bacillus megatarium), and Archaea ( Haloarcula marismortui) were performed. For extractions of both planktonic cultures and spiked Mars simulated regolith, FTA ® paper demonstrated the highest sensitivity, with detection as low as ˜1×10 1 cells and ˜3.3×10 2 cells, respectively. In addition to the highest sensitivity, custom modified application of FTA ® paper extraction protocol is the simplest in terms of incorporation into MASSE and displayed little bias in sensitivity with respect to prokaryotic cell type. The implementation of FTA paper for environmental microbiology investigations appears to be a viable and effective option potentially negating the need for other pre-concentration steps such as filtration and negating concerns regarding extraction efficiency of cells. In addition to investigations on useful technology for upstream sample handling in MASSE, we have also evaluated the potential for μTAS to be employed in the MASSE instrument by employing proprietary lab-on-a-chip development technology to investigate the potential for microfluidic cell lysis of different prokaryotic cells employing both chemical and biological lysis agents. Real-time bright-field microscopy and quantitative PMT detection indicated that that gram positive, gram negative and archaeal cells were effectively lyzed in a few seconds using the microfluidic chip protocol developed. This included employing a lysis buffer with

  16. Daratumumab-mediated lysis of primary multiple myeloma cells is enhanced in combination with the human anti-KIR antibody IPH2102 and lenalidomide

    DEFF Research Database (Denmark)

    Nijhof, I. S.; Lammerts van Bueren, J. J.; van Kessel, B.

    2015-01-01

    Despite recent treatment improvements, multiple myeloma remains an incurable disease. Since antibody-dependent cell-mediated cytotoxicity is an important effector mechanism of daratumumab, we explored the possibility of improving daratumumab-mediated cell-mediated cytotoxicity by blocking natural...... killer cell inhibitory receptors with the human monoclonal anti-KIR antibody IPH2102, next to activation of natural killer cells with the immune modulatory drug lenalidomide. In 4-hour antibody-dependent cell-mediated cytotoxicity assays, IPH2102 did not induce lysis of multiple myeloma cell lines...... effective treatment strategies can be designed for multiple myeloma by combining daratumumab with agents that independently modulate natural killer cell function....

  17. Tumour-infiltrating lymphocytes mediate lysis of autologous squamous cell carcinomas of the head and neck

    DEFF Research Database (Denmark)

    Hald, Jeppe; Rasmussen, N; Claesson, Mogens Helweg

    1995-01-01

    Tumour-infiltrating lymphocytes (TIL) and tumours from six patients with squamous cell carcinomas of the head and neck (SCCHN) were investigated. The six tumours all expressed major histocompatibility complex (MHC) class I antigens both in vivo and as tumor cell lines grown in vitro. In addition...

  18. Prevention of red cell lysis in artesunate-treated rats: A role for ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-01-19

    Jan 19, 2009 ... mice caused a decrease in the nucleated cell counts in the peripheral blood, the .... Society of hematology, annual meeting abstracts; abstract 1049: p. 106. Salman 141. Leopold J ... Trans Res. Soc. London B. Biol. Sci. 354:.

  19. Soil pretreatment and fast cell lysis for direct polymerase chain reaction from forest soils for terminal restriction fragment length polymorphism analysis of fungal communities

    Directory of Open Access Journals (Sweden)

    Fei Cheng

    Full Text Available Abstract Humic substances in soil DNA samples can influence the assessment of microbial diversity and community composition. Using multiple steps during or after cell lysis adds expenses, is time-consuming, and causes DNA loss. A pretreatment of soil samples and a single step DNA extraction may improve experimental results. In order to optimize a protocol for obtaining high purity DNA from soil microbiota, five prewashing agents were compared in terms of their efficiency and effectiveness in removing soil contaminants. Residual contaminants were precipitated by adding 0.6 mL of 0.5 M CaCl2. Four cell lysis methods were applied to test their compatibility with the pretreatment (prewashing + Ca2+ flocculation and to ultimately identify the optimal cell lysis method for analyzing fungal communities in forest soils. The results showed that pretreatment with TNP + Triton X-100 + skim milk (100 mM Tris, 100 mM Na4P2O7, 1% polyvinylpyrrolidone, 100 mM NaCl, 0.05% Triton X-100, 4% skim milk, pH 10.0 removed most soil humic contaminants. When the pretreatment was combined with Ca2+ flocculation, the purity of all soil DNA samples was further improved. DNA samples obtained by the fast glass bead-beating method (MethodFGB had the highest purity. The resulting DNA was successfully used, without further purification steps, as a template for polymerase chain reaction targeting fungal internal transcribed spacer regions. The results obtained by terminal restriction fragment length polymorphism analysis indicated that the MethodFGB revealed greater fungal diversity and more distinctive community structure compared with the other methods tested. Our study provides a protocol for fungal cell lysis in soil, which is fast, convenient, and effective for analyzing fungal communities in forest soils.

  20. Stretching single fibrin fibers hampers their lysis.

    Science.gov (United States)

    Li, Wei; Lucioni, Tomas; Li, Rongzhong; Bonin, Keith; Cho, Samuel S; Guthold, Martin

    2017-09-15

    Blood clots, whose main structural component is a mesh of microscopic fibrin fibers, experience mechanical strain from blood flow, clot retraction and interactions with platelets and other cells. We developed a transparent, striated and highly stretchable substrate made from fugitive glue (a styrenic block copolymer) to investigate how mechanical strain affects lysis of single, suspended fibrin fibers. In this suspended fiber assay, lysis manifested itself by fiber elongation, thickening (disassembly), fraying and collapse. Stretching single fibrin fibers significantly hampered their lysis. This effect was seen in uncrosslinked and crosslinked fibers. Crosslinking (without stretching) also hampered single fiber lysis. Our data suggest that strain is a novel mechanosensitive factor that regulates blood clot dissolution (fibrinolysis) at the single fiber level. At the molecular level of single fibrin molecules, strain may distort, or hinder access to, plasmin cleavage sites and thereby hamper lysis. Fibrin fibers are the major structural component of a blood clot. We developed a highly stretchable substrate made from fugitive glue and a suspended fibrin fiber lysis assay to investigate the effect of stretching on single fibrin fibers lysis. The key findings from our experiments are: 1) Fibers thicken and elongate upon lysis; 2) stretching strongly reduces lysis; 3) this effect is more pronounced for uncrosslinked fibers; and 4) stretching fibers has a similar effect on reducing lysis as crosslinking fibers. At the molecular level, strain may distort plasmin cleavage sites, or restrict access to those sites. Our results suggest that strain may be a novel mechanobiological factor that regulates fibrinolysis. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  1. Influence of polymer architecture on antigens camouflage, CD47 protection and complement mediated lysis of surface grafted red blood cells.

    Science.gov (United States)

    Chapanian, Rafi; Constantinescu, Iren; Rossi, Nicholas A A; Medvedev, Nadia; Brooks, Donald E; Scott, Mark D; Kizhakkedathu, Jayachandran N

    2012-11-01

    Hyperbranched polyglycerol (HPG) and polyethylene glycol (PEG) polymers with similar hydrodynamic sizes in solution were grafted to red blood cells (RBCs) to investigate the impact of polymer architecture on the cell structure and function. The hydrodynamic sizes of polymers were calculated from the diffusion coefficients measured by pulsed field gradient NMR. The hydration of the HPG and PEG was determined by differential scanning calorimetry analyses. RBCs grafted with linear PEG had different properties compared to the compact HPG grafted RBCs. HPG grafted RBCs showed much higher electrophoretic mobility values than PEG grafted RBCs at similar grafting concentrations and hydrodynamic sizes indicating differences in the structure of the polymer exclusion layer on the cell surface. PEG grafting impacted the deformation properties of the membrane to a greater degree than HPG. The complement mediated lysis of the grafted RBCs was dependent on the type of polymer, grafting concentration and molecular size of grafted chains. At higher molecular weights and graft concentrations both HPG and PEG triggered complement activation. The magnitude of activation was higher with HPG possibly due to the presence of many hydroxyl groups per molecule. HPG grafted RBCs showed significantly higher levels of CD47 self-protein accessibility than PEG grafted RBCs at all grafting concentrations and molecular sizes. PEG grafted polymers provided, in general, a better shielding and protection to ABO and minor antigens from antibody recognition than HPG polymers, however, the compact HPGs provided greater protection of certain antigens on the RBC surface. Our data showed that HPG 20 kDa and HPG 60 kDa grafted RBCs exhibited properties that are more comparable to the native RBC than PEG 5 kDa and PEG 10 kDa grafted RBCs of comparable hydrodynamic sizes. The study shows that small compact polymers such as HPG 20 kDa have a greater potential in the generation of functional RBC for therapeutic

  2. Cell Lysis and Detoxification of Cyanotoxins Using a Novel Combination of Microbubble Generation and Plasma Microreactor Technology for Ozonation

    Directory of Open Access Journals (Sweden)

    Jagroop Pandhal

    2018-04-01

    Full Text Available There has been a steady rise in the incidences of algal blooms globally, and worryingly, there is increasing evidence that changes in the global climate are leading to a shift toward cyanobacterial blooms. Many cyanobacterial genera are harmful, producing several potent toxins, including microcystins, for which there are over 90 described analogues. There are a wide range of negative effects associated with these toxins including gastroenteritis, cytotoxicity, hepatotoxicity and neurotoxicity. Although a variety of oxidation based treatment methods have been described, ozonation and advanced oxidation are acknowledged as most effective as they readily oxidise microcystins to non-toxic degradation products. However, most ozonation technologies have challenges for scale up including high costs and sub-optimum efficiencies, hence, a low cost and scalable ozonation technology is needed. Here we designed a low temperature plasma dielectric barrier discharge (DBD reactor with an incorporated fluidic oscillator for microbubble delivery of ozone. Both technologies have the potential to drastically reduce the costs of ozonation at scale. Mass spectrometry analysis revealed very rapid (<2 min destruction of two pure microcystins (MC-LR and MC-RR, together with removal of by-products even at low flow rate 1 L min−1 where bubble size was 0.56–0.6 mm and the ozone concentration within the liquid was 20 ppm. Toxicity levels were calculated through protein phosphatase inhibition assays and indicated loss of toxicity as well as confirming the by-products were also non-toxic. Finally, treatment of whole Microcystis aeruginosa cells showed that even at these very low ozone levels, cells can be killed and toxins (MC-LR and Desmethyl MC-LR removed. Little change was observed in the first 20 min of treatment followed by rapid increase in extracellular toxins, indicating cell lysis, with most significant release at the higher 3 L min−1 flow rate compared to 1 L

  3. Factors influencing lysis time stochasticity in bacteriophage λ

    Directory of Open Access Journals (Sweden)

    Dennehy John J

    2011-08-01

    Full Text Available Abstract Background Despite identical genotypes and seemingly uniform environments, stochastic gene expression and other dynamic intracellular processes can produce considerable phenotypic diversity within clonal microbes. One trait that provides a good model to explore the molecular basis of stochastic variation is the timing of host lysis by bacteriophage (phage. Results Individual lysis events of thermally-inducible λ lysogens were observed using a temperature-controlled perfusion chamber mounted on an inverted microscope. Both mean lysis time (MLT and its associated standard deviation (SD were estimated. Using the SD as a measure of lysis time stochasticity, we showed that lysogenic cells in controlled environments varied widely in lysis times, and that the level of lysis time stochasticity depended on allelic variation in the holin sequence, late promoter (pR' activity, and host growth rate. In general, the MLT was positively correlated with the SD. Both lower pR' activities and lower host growth rates resulted in larger SDs. Results from premature lysis, induced by adding KCN at different time points after lysogen induction, showed a negative correlation between the timing of KCN addition and lysis time stochasticity. Conclusions Taken together with results published by others, we conclude that a large fraction of λ lysis time stochasticity is the result of random events following the expression and diffusion of the holin protein. Consequently, factors influencing the timing of reaching critical holin concentrations in the cell membrane, such as holin production rate, strongly influence the mean lysis time and the lysis time stochasticity.

  4. Spontaneous Tumor Lysis Syndrome

    Directory of Open Access Journals (Sweden)

    Alicia C. Weeks MD

    2015-08-01

    Full Text Available Tumor lysis syndrome (TLS is a known complication of malignancy and its treatment. The incidence varies on malignancy type, but is most common with hematologic neoplasms during cytotoxic treatment. Spontaneous TLS is thought to be rare. This case study is of a 62-year-old female admitted with multisystem organ failure, with subsequent diagnosis of aggressive B cell lymphoma. On admission, laboratory abnormalities included renal failure, elevated uric acid (20.7 mg/dL, and 3+ amorphous urates on urinalysis. Oliguric renal failure persisted despite aggressive hydration and diuretic use, requiring initiation of hemodialysis prior to chemotherapy. Antihyperuricemic therapy and hemodialysis were used to resolve hyperuricemia. However, due to multisystem organ dysfunction syndrome with extremely poor prognosis, the patient ultimately expired in the setting of a terminal ventilator wean. Although our patient did not meet current TLS criteria, she required hemodialysis due to uric acid nephropathy, a complication of TLS. This poses the clinical question of whether adequate diagnostic criteria exist for spontaneous TLS and if the lack of currently accepted guidelines has resulted in the underestimation of its incidence. Allopurinol and rasburicase are commonly used for prevention and treatment of TLS. Although both drugs decrease uric acid levels, allopurinol mechanistically prevents formation of the substrate rasburicase acts to solubilize. These drugs were administered together in our patient, although no established guidelines recommend combined use. This raises the clinical question of whether combined therapy is truly beneficial or, conversely, detrimental to patient outcomes.

  5. CD20-Specific Immunoligands Engaging NKG2D Enhance γδ T Cell-Mediated Lysis of Lymphoma Cells

    DEFF Research Database (Denmark)

    Peipp, M.; Wesch, D.; Oberg, H. H.

    2017-01-01

    Human γδ T cells are innate-like T cells which are able to kill a broad range of tumour cells and thus may have potential for cancer immunotherapy. The activating receptor natural killer group 2 member D (NKG2D) plays a key role in regulating immune responses driven by γδ T cells. Here, we explor...

  6. Solubilization of proteins: the importance of lysis buffer choice.

    Science.gov (United States)

    Peach, Mandy; Marsh, Noelle; Miskiewicz, Ewa I; MacPhee, Daniel J

    2015-01-01

    The efficient extraction of proteins of interest from cells and tissues is not always straightforward. Here we demonstrate the differences in extraction of the focal adhesion protein Kindlin-2 from choriocarcinoma cells using NP-40 and RIPA lysis buffer. Furthermore, we demonstrate the use of a more denaturing urea/thiourea lysis buffer for solubilization, by comparing its effectiveness for solubilization of small heat-shock proteins from smooth muscle with the often utilized RIPA lysis buffer. Overall, the results demonstrate the importance of establishing the optimal lysis buffer for specific protein solubilization within the experimental workflow.

  7. Lysis of endogenously infected CD4+ T cell blasts by rIL-2 activated autologous natural killer cells from HIV-infected viremic individuals.

    Directory of Open Access Journals (Sweden)

    Manuela Fogli

    2008-07-01

    Full Text Available Understanding the cellular mechanisms that ensure an appropriate innate immune response against viral pathogens is an important challenge of biomedical research. In vitro studies have shown that natural killer (NK cells purified from healthy donors can kill heterologous cell lines or autologous CD4+ T cell blasts exogenously infected with several strains of HIV-1. However, it is not known whether the deleterious effects of high HIV-1 viremia interferes with the NK cell-mediated cytolysis of autologous, endogenously HIV-1-infected CD4+ T cells. Here, we stimulate primary CD4+ T cells, purified ex vivo from HIV-1-infected viremic patients, with PHA and rIL2 (with or without rIL-7. This experimental procedure allows for the significant expansion and isolation of endogenously infected CD4+ T cell blasts detected by intracellular staining of p24 HIV-1 core antigen. We show that, subsequent to the selective down-modulation of MHC class-I (MHC-I molecules, HIV-1-infected p24(pos blasts become partially susceptible to lysis by rIL-2-activated NK cells, while uninfected p24(neg blasts are spared from killing. This NK cell-mediated killing occurs mainly through the NKG2D activation pathway. However, the degree of NK cell cytolytic activity against autologous, endogenously HIV-1-infected CD4+ T cell blasts that down-modulate HLA-A and -B alleles and against heterologous MHC-I(neg cell lines is particularly low. This phenomenon is associated with the defective surface expression and engagement of natural cytotoxicity receptors (NCRs and with the high frequency of the anergic CD56(neg/CD16(pos subsets of highly dysfunctional NK cells from HIV-1-infected viremic patients. Collectively, our data demonstrate that the chronic viral replication of HIV-1 in infected individuals results in several phenotypic and functional aberrancies that interfere with the NK cell-mediated killing of autologous p24(pos blasts derived from primary T cells.

  8. Type i CD20 antibodies recruit the B cell receptor for complement-dependent lysis of malignant B cells

    DEFF Research Database (Denmark)

    Engelberts, P. J.; Voorhorst, M.; Schuurman, J.

    2016-01-01

    . We hypothesized that CD20 Ab-induced clustering of the IgM or IgG BCR was involved in accessory CDC. Indeed, accessory CDC was consistently observed in B cell lines expressing an IgM BCR and in some cell lines expressing an IgG BCR, but it was absent in BCR- B cell lines. A direct relationship...... between BCR expression and accessory CDC was established by transfecting the BCR into CD20+ cells: OFA-F(ab')2 fragments were able to induce CDC in the CD20+BCR+ cell population, but not in the CD20+BCR- population. Importantly, OFA-F(ab')2 fragments were able to induce CDC ex vivo in malignant B cells...... isolated from patients with mantle cell lymphoma and Waldenström macroglobulinemia. In summary, accessory CDC represents a novel effector mechanism that is dependent on type I CD20 Ab-induced BCR clustering. Accessory CDC may contribute to the excellent capacity of type I CD20 Abs to induce CDC...

  9. Dextran sulphate crowding and sodium deoxycholate lysis of primary breast fibroblast cells achieve extracellular matrix deposition and decellularization for breast cancer stem cell culture

    Directory of Open Access Journals (Sweden)

    Aroem Naruni

    2016-01-01

    Full Text Available AbstrakLatar belakang: Lingkungan mikro yaitu sel stromal dam matriks ekstraseluler saat ini dinyatakansebagai kontributor dalam perkembangan tumor. Beberapa penelitian telah mengembangkan matriksekstraseluler yang mendukung perkembangan sel in vitro. Matriks ekstraseluler adalah suatu komplekssusunan supramolekuler dari berbagai macam glycoprotein dan proteoglycan. Matriks ekstraselulermenyediakan integritas jaringan, bertindak sebagai scaffold alami tempat sel melekat dan berinteraksiserta berperan sebagai reservoir pertumbuhan sel. Penelitian ini bertujuan untuk mendapatkan deposisidan deselularisasi yang optimal pada matriks ekstraseluler.Metode: Dalam penelitian ini, kami mengembangkan cells crowder untuk meningkatkan deposit matriksekstraseluler dari kultur sel primer fibroblast payudara yang diperoleh dari spesimen hasil operasimammoplasty. Dextran 500 kDa ditambahkan dalam media kultur DMEM lengkap yang telah ditambahkan0.5% FBS dan 100μM L-ascorbic acid 2-phosphate. Setelah tujuh hari, sel dilisis dengan menggunakanSodium Deoxycolate (DOC.Hasil: Deposisi matriks ekstraseluler dan proses deselulerisasi dari sel primer fibroblas payudara dapatterdeteksi dengan menggunakan antibodi Rabbit anti human fibronectin yang selanjutnya ditambahkandengan anti rabbit IgG yang telah dikonjugasi dengan Alexa Fluor 488.Kesimpulan: Penambahan dextran sulfat dan prosesing lysis dengan sodium deoxycolate dapatmeningkatkan deposisi dan menghasilkan deselularisasi matriks ekstraseluler. (Health Science Journalof Indonesia 2015;6:43-7Kata kunci: matriks ekstra selular, kanker mammae, stem cell, sel fibroblast AbstractBackground: The microenvironment including stromal cells and extracellular matrix (ECM is now consideredan active contributor to tumor progression. Certain studies have developed ECM which supports a suitable cellulargrowth in vitro. The ECM is a complex supramolecular assembly of a variety of glycoproteins and proteoglycans

  10. Diphtheria toxin- and Pseudomonas A toxin-mediated apoptosis. ADP ribosylation of elongation factor-2 is required for DNA fragmentation and cell lysis and synergy with tumor necrosis factor-alpha.

    Science.gov (United States)

    Morimoto, H; Bonavida, B

    1992-09-15

    We have reported that diphtheria toxin (DTX) mediates target cell lysis and intranucleosomal DNA fragmentation (apoptosis) and also synergizes with TNF-alpha. In this paper, we examined which step in the pathway of DTX-mediated inhibition of protein synthesis was important for induction of cytolytic activity and for synergy. Using a DTX-sensitive tumor cell line, we first examined the activity of the mutant CRM 197, which does not catalyze the ADP ribosylation of elongation factor-2 (EF-2). CRM 197 was not cytolytic for target cells and did not mediate intranucleosomal DNA fragmentation of viable cells. The failure of CRM 197 to mediate target cell lysis suggested that the catalytic activity of DTX is prerequisite for target cell lysis. This was corroborated by demonstrating that MeSAdo, which blocks the biosynthesis of diphthamide, inhibited DTX-mediated protein synthesis inhibition and also blocked target cell lysis. Furthermore, the addition of nicotinamide, which competes with NAD+ on the DTX action site of EF-2, also blocked DTX-mediated lysis. These findings suggest that ADP-ribosylation of EF-2 may be a necessary step in the pathway leading to target cell lysis. In contrast to the sensitive line, the SKOV-3 tumor cell line is sensitive to protein synthesis inhibition by DTX but is not susceptible to cytolysis and apoptosis by DTX. Thus, protein synthesis inhibition by DTX is not sufficient to mediate target cell lysis. The synergy in cytotoxicity obtained with the combination of DTX and TNF-alpha was examined in order to determine the pathway mediated by DTX in synergy. Like the direct lysis by DTX, synergy was significantly reduced by MeSAdo and by nicotinamide. Furthermore, synergy was not observed with combination of CRM 197 and TNF-alpha. These results demonstrate that, in synergy, DTX may utilize the same pathway required for its cytolytic activity. Pseudomonas aeruginosa exotoxin shared most the properties shown for DTX. Altogether, these findings

  11. Type I CD20 Antibodies Recruit the B Cell Receptor for Complement-Dependent Lysis of Malignant B Cells

    NARCIS (Netherlands)

    Engelberts, Patrick J.; Voorhorst, Marleen; Schuurman, Janine; van Meerten, Tom; Bakker, Joost M.; Vink, Tom; Mackus, Wendy J. M.; Breij, Esther C. W.; Derer, Stefanie; Valerius, Thomas; van de Winkel, Jan G. J.; Parren, Paul W. H. I.; Beurskens, Frank J.

    2016-01-01

    Human IgG1 type I CD20 Abs, such as rituximab and ofatumumab (OFA), efficiently induce complement-dependent cytotoxicity (CDC) of CD20(+) B cells by binding of C1 to hexamerized Fc domains. Unexpectedly, we found that type I CD20 Ab F(ab ')2 fragments, as well as C1q-binding-deficient IgG mutants,

  12. Maintenance, endogeneous, respiration, lysis, decay and predation

    DEFF Research Database (Denmark)

    loosdrecht, Marc C. M. Van; Henze, Mogens

    1999-01-01

    mechanism is microbiologically correct. The lysis/decay model mechanism is a strongly simplified representation of reality. This paper tries to review the processes grouped under endogenous respiration in activated sludge models. Mechanisms and processes such as maintenance, lysis, internal and external...... decay, predation and death-regeneration are discussed. From recent microbial research it has become evident that cells do not die by themselves. Bacteria are however subject to predation by protozoa. Bacteria store reserve polymers that in absence of external substrate are used for growth...

  13. Lysis from without

    Science.gov (United States)

    2011-01-01

    In this commentary I consider use of the term “lysis from without” (LO) along with the phenomenon's biological relevance. LO originally described an early bacterial lysis induced by high-multiplicity virion adsorption and that occurs without phage production (here indicated as LOV). Notably, this is more than just high phage multiplicities of adsorption leading to bacterial killing. The action on bacteria of exogenously supplied phage lysin, too, has been described as a form of LO (here, LOL). LOV has been somewhat worked out mechanistically for T4 phages, has been used to elucidate various phage-associated phenomena including discovery of the phage eclipse, may be relevant to phage ecology, and, with resistance to LO (LOR), is blocked by certain phage gene products. Speculation as to the impact of LOV on phage therapy also is fairly common. Since LOV assays are relatively easily performed and not all phages are able to induce LOV, a phage's potential to lyse bacteria without first infecting should be subject to at least in vitro experimental confirmation before the LOV label is applied. The term “abortive infection” may be used more generally to describe non-productive phage infections that kill bacteria. PMID:21687534

  14. Anti-PD-L1/TGFβR2 (M7824) fusion protein induces immunogenic modulation of human urothelial carcinoma cell lines, rendering them more susceptible to immune-mediated recognition and lysis.

    Science.gov (United States)

    Grenga, Italia; Donahue, Renee N; Gargulak, Morgan L; Lepone, Lauren M; Roselli, Mario; Bilusic, Marijo; Schlom, Jeffrey

    2018-03-01

    Avelumab has recently been approved by the Food and Drug Administration for the therapy of Merkel cell carcinoma and urothelial carcinoma. M7824 is a novel first-in-class bifunctional fusion protein comprising a monoclonal antibody against programmed death-ligand 1 (PD-L1, avelumab), fused to the extracellular domain of human transforming growth factor beta (TGFβ) receptor 2, which functions as a TGFβ "trap." Advanced urothelial tumors have been shown to express TGFβ, which possesses immunosuppressive properties that promote cancer progression and metastasis. The rationale for a combined molecule is to block the PD-1/PD-L1 interaction between tumor cells and immune cell infiltrate and simultaneously reduce or eliminate TGFβ from the tumor microenvironment. In this study, we explored the effect of M7824 on invasive urothelial carcinoma cell lines. Human urothelial (transitional cell) carcinoma cell lines HTB-4, HTB-1, and HTB-5 were treated with M7824, M7824mut (M7824 that is mutated in the anti-PD-L1 portion of the molecule and thus does not bind PD-L1), anti-PD-L1 (avelumab), or IgG1 isotype control monoclonal antibody, and were assessed for gene expression, cell-surface phenotype, and sensitivity to lysis by TRAIL, antigen-specific cytotoxic T lymphocytes and natural killer cells. M7824 retains the ability to mediate antibody-dependent cellular cytotoxicity of tumor cells, although in some cases to a lesser extent than anti-PD-L1. However, compared to anti-PD-L1, M7824 increases (A) gene expression of molecules involved in T-cell trafficking in the tumor (e.g., CXCL11), (B) TRAIL-mediated tumor cell lysis, and (C) antigen-specific CD8 + T-cell-mediated lysis of tumor cells. These studies demonstrate the immunomodulatory properties of M7824 on both tumor cell phenotype and immune-mediated lysis. Compared to anti-PD-L1 or M7824mut, M7824 induces immunogenic modulation of urothelial carcinoma cell lines, rendering them more susceptible to immune

  15. Permeabilization and lysis of Pseudomonas pseudoalcaligenes cells by triton X-100 for efficient production of D-malate

    NARCIS (Netherlands)

    Werf, M.J. van der; Hartmans, S.; Tweel, W.J.J. van den

    1995-01-01

    Pseudomonas pseudoalcaligenes can only form d-malate from maleate after incubation of the cells with a solvent or a detergent. The effect of the detergent Triton X-100 on d-malate production was studied in more detail. The longer the cells were incubated with Triton X-100, the higher was the

  16. Preclinical Testing of an Oncolytic Parvovirus: Standard Protoparvovirus H-1PV Efficiently Induces Osteosarcoma Cell Lysis In Vitro.

    Science.gov (United States)

    Geiss, Carsten; Kis, Zoltán; Leuchs, Barbara; Frank-Stöhr, Monika; Schlehofer, Jörg R; Rommelaere, Jean; Dinsart, Christiane; Lacroix, Jeannine

    2017-10-17

    Osteosarcoma is the most frequent malignant disease of the bone. On the basis of early clinical experience in the 1960s with H-1 protoparvovirus (H-1PV) in osteosarcoma patients, this effective oncolytic virus was selected for systematic preclinical testing on various osteosarcoma cell cultures. A panel of five human osteosarcoma cell lines (CAL 72, H-OS, MG-63, SaOS-2, U-2OS) was tested. Virus oncoselectivity was confirmed by infecting non-malignant human neonatal fibroblasts and osteoblasts used as culture models of non-transformed mesenchymal cells. H-1PV was found to enter osteosarcoma cells and to induce viral DNA replication, transcription of viral genes, and translation to viral proteins. After H-1PV infection, release of infectious viral particles from osteosarcoma cells into the supernatant indicated successful viral assembly and egress. Crystal violet staining revealed progressive cytomorphological changes in all osteosarcoma cell lines. Infection of osteosarcoma cell lines with the standard H-1PV caused an arrest of the cell cycle in the G2 phase, and these lines had a limited capacity for standard H-1PV virus replication. The cytotoxicity of wild-type H-1PV virus towards osteosarcoma cells was compared in vitro with that of two variants, Del H-1PV and DM H-1PV, previously described as fitness variants displaying higher infectivity and spreading in human transformed cell lines of different origins. Surprisingly, wild-type H-1PV displayed the strongest cytostatic and cytotoxic effects in this analysis and thus seems the most promising for the next preclinical validation steps in vivo.

  17. Preclinical Testing of an Oncolytic Parvovirus: Standard Protoparvovirus H-1PV Efficiently Induces Osteosarcoma Cell Lysis In Vitro

    Directory of Open Access Journals (Sweden)

    Carsten Geiss

    2017-10-01

    Full Text Available Osteosarcoma is the most frequent malignant disease of the bone. On the basis of early clinical experience in the 1960s with H-1 protoparvovirus (H-1PV in osteosarcoma patients, this effective oncolytic virus was selected for systematic preclinical testing on various osteosarcoma cell cultures. A panel of five human osteosarcoma cell lines (CAL 72, H-OS, MG-63, SaOS-2, U-2OS was tested. Virus oncoselectivity was confirmed by infecting non-malignant human neonatal fibroblasts and osteoblasts used as culture models of non-transformed mesenchymal cells. H-1PV was found to enter osteosarcoma cells and to induce viral DNA replication, transcription of viral genes, and translation to viral proteins. After H-1PV infection, release of infectious viral particles from osteosarcoma cells into the supernatant indicated successful viral assembly and egress. Crystal violet staining revealed progressive cytomorphological changes in all osteosarcoma cell lines. Infection of osteosarcoma cell lines with the standard H-1PV caused an arrest of the cell cycle in the G2 phase, and these lines had a limited capacity for standard H-1PV virus replication. The cytotoxicity of wild-type H-1PV virus towards osteosarcoma cells was compared in vitro with that of two variants, Del H-1PV and DM H-1PV, previously described as fitness variants displaying higher infectivity and spreading in human transformed cell lines of different origins. Surprisingly, wild-type H-1PV displayed the strongest cytostatic and cytotoxic effects in this analysis and thus seems the most promising for the next preclinical validation steps in vivo.

  18. Use of conivaptan to allow aggressive hydration to prevent tumor lysis syndrome in a pediatric patient with large-cell lymphoma and SIADH.

    Science.gov (United States)

    Rianthavorn, Pornpimol; Cain, Joan P; Turman, Martin A

    2008-08-01

    The available treatment options for hyponatremia secondary to SIADH are limited and not completely effective. Conivaptan is a vasopressin 1a and 2 receptor antagonist recently approved by the US Food and Drug Administration (FDA) for treating euvolemic and hypervolemic hyponatremia in adult patients. However, data on efficacy and safety of conivaptan in pediatrics are limited. We report a case of a 13-year-old boy with extensively metastasized anaplastic large-cell lymphoma. He also developed hyponatremia due to syndrome of inappropriate antidiuretic hormone secretion (SIADH) prior to chemotherapy initiation. SIADH management in this case was complicated when fluid restriction was not safely attainable. Conivaptan played a significant role in this situation by allowing provision of a large amount of intravenous fluid prior to and during induction chemotherapy. It proved to be an important component in preventing uric acid nephropathy/tumor lysis syndrome. Conivaptan induced free-water clearance as indicated by increased urine output and decreased urine osmolality. The patient responded to conivaptan without any adverse effects.

  19. Kinetics of cell lysis for Microcystis aeruginosa and Nitzschia palea in the exposure to β-cyclocitral

    International Nuclear Information System (INIS)

    Chang, De-Wei; Hsieh, Meng-Ling; Chen, Yan-Min; Lin, Tsair-Fuh; Chang, Jo-Shu

    2011-01-01

    The effect of an algal metabolite, β-cyclocitral, on the cell integrity of two cyanobacteria and one diatom was investigated. The cyanobacteria, Microcystis aeruginosa PCC 7005 and PCC 7820, and the diatom, Nitzschia palea, were exposed to various concentrations of β-cyclocitral. Scanning electron microscope (SEM) results indicate that the cells of tested species were greatly altered after being exposed to β-cyclocitral. A flow cytometer coupled with the SYTOX stain and chlorophyll-a auto-fluorescence was used to quantify the effect of β-cyclocitral on cell integrity for the tested cyanobacteria and diatom. Kinetic experiments show that about 5-10 mg L -1 of β-cyclocitral for the two M. aeruginosa strains and a much lower concentration, 0.1-0.5 mg L -1 , for N. palea were needed to cause 15-20% of cells to rupture. When the β-cyclocitral concentration was increased to 200-1000 mg L -1 for M. aeruginosa and 5-10 mg L -1 for N. palea, almost all the cells ruptured between 8 and 24 h. A first-order kinetic model is able to describe the data of cell integrity over time. The extracted rate constant values well correlate with the applied β-cyclocitral dosages. The obtained kinetic parameters may be used to estimate β-cyclocitral dosage and contact time required for the control of cyanobacteria and diatoms in water bodies.

  20. Preclinical Testing of an Oncolytic Parvovirus: Standard Protoparvovirus H-1PV Efficiently Induces Osteosarcoma Cell Lysis In Vitro

    OpenAIRE

    Carsten Geiss; Zoltán Kis; Barbara Leuchs; Monika Frank-Stöhr; Jörg R. Schlehofer; Jean Rommelaere; Christiane Dinsart; Jeannine Lacroix

    2017-01-01

    Osteosarcoma is the most frequent malignant disease of the bone. On the basis of early clinical experience in the 1960s with H-1 protoparvovirus (H-1PV) in osteosarcoma patients, this effective oncolytic virus was selected for systematic preclinical testing on various osteosarcoma cell cultures. A panel of five human osteosarcoma cell lines (CAL 72, H-OS, MG-63, SaOS-2, U-2OS) was tested. Virus oncoselectivity was confirmed by infecting non-malignant human neonatal fibroblasts and osteoblasts...

  1. Alloreactive cytotoxic T lymphocytes from aged mice express increased lysis of autologous and third-party target cells

    NARCIS (Netherlands)

    Kruisbeek, A.M.; Steinmeier, F.A.

    1980-01-01

    Much data support the notion that with increasing age a decline in T cell effector function occurs. In the present study, qualitative rather than quantitative age-related changes in vitro alloreactive cytotoxic T lymphocyte (CTL) responses were observed. The level of specific alloreactive CTL

  2. Application of Doehlert experimental design in the optimization of experimental variables for the Pseudozyma sp. (CCMB 306 and Pseudozyma sp. (CCMB 300 cell lysis

    Directory of Open Access Journals (Sweden)

    Amanda Reges de Sena

    2012-12-01

    Full Text Available This study aimed to verify the influence of pH and temperature on the lysis of yeast using experimental design. In this study, the enzymatic extract containing β-1,3-glucanase and chitinase, obtained from the micro-organism Moniliophthora perniciosa, was used. The experiment showed that the best conditions for lysis of Pseudozyma sp. (CCMB 306 and Pseudozyma sp. (CCMB 300 by lytic enzyme were pH 4.9 at 37 ºC and pH 3.9 at 26.7 ºC, respectively. The lytic enzyme may be used for obtaining various biotechnology products from yeast.

  3. Prevalence of Complement-Mediated Cell Lysis-like Gene (sicG) in Streptococcus dysgalactiae subsp. equisimilis Isolates From Japan (2014-2016).

    Science.gov (United States)

    Takahashi, Takashi; Fujita, Tomohiro; Shibayama, Akiyoshi; Tsuyuki, Yuzo; Yoshida, Haruno

    2017-07-01

    Streptococcus dysgalactiae subsp. equisimilis (SDSE; a β-hemolytic streptococcus of human or animal origin) infections are emerging worldwide. We evaluated the clonal distribution of complement-mediated cell lysis-like gene (sicG) among SDSE isolates from three central prefectures of Japan. Group G/C β-hemolytic streptococci were collected from three institutions from April 2014 to March 2016. Fifty-five strains (52 from humans and three from animals) were identified as SDSE on the basis of 16S rRNA sequencing data.; they were obtained from 25 sterile (blood, joint fluid, and cerebrospinal fluid) and 30 non-sterile (skin-, respiratory tract-, and genitourinary tract-origin) samples. emm genotyping, multilocus sequence typing, sicG amplification/sequencing, and random amplified polymorphic DNA (RAPD) analysis of sicG-positive strains were performed. sicG was detected in 30.9% of the isolates (16 human and one canine) and the genes from the 16 human samples (blood, 10; open pus, 3; sputum, 2; throat swab, 1) and one canine sample (open pus) showed the same sequence pattern. All sicG-harboring isolates belonged to clonal complex (CC) 17, and the most prevalent emm type was stG6792 (82.4%). There was a significant association between sicG presence and the development of skin/soft tissue infections. CC17 isolates with sicG could be divided into three subtypes by RAPD analysis. CC17 SDSE harboring sicG might have spread into three closely-related prefectures in central Japan during 2014-2016. Clonal analysis of isolates from other areas might be needed to monitor potentially virulent strains in humans and animals. © The Korean Society for Laboratory Medicine

  4. Synthesis and functioning of the colicin E1 lysis protein: Comparison with the colicin A lysis protein

    International Nuclear Information System (INIS)

    Cavard, D.

    1991-01-01

    The colicin E1 lysis protein, CelA, was identified as a 3-kDa protein in induced cells of Escherichia coli K-12 carrying pColE1 by pulse-chase labeling with either [ 35 S]cysteine or [ 3 H]lysine. This 3-kDa protein was acylated, as shown by [2- 3 H]glycerol labeling, and seemed to correspond to the mature CelA protein. The rate of modification and processing of CelA was different from that observed for Cal, the colicin A lysis protein. In contrast to Cal, no intermediate form was detected for CelA, no signal peptide accumulated, and no modified precursor form was observed after globomycin treatment. Thus, the rate of synthesis would not be specific to lysis proteins. Solubilization in sodium dodecyl sulfate of the mature forms of both CelA and Cal varied similarly at the time of colicin release, indicating a change in lysis protein structure. This particular property would play a role in the mechanism of colicin export. The accumulation of the signal peptide seems to be a factor determining the toxicity of the lysis proteins since CelA provoked less cell damage than Cal. Quasi-lysis and killing due to CelA were higher in degP mutants than in wild-type cells. They were minimal in pldA mutants

  5. β-1,3 Glucanases e quitinases: aplicação na lise de leveduras e inibição de fungos β-1,3 glucanases and chitinases: application in the yeast cell lysis and fungi inhibition

    Directory of Open Access Journals (Sweden)

    Luciana Francisco Fleuri

    2008-08-01

    Full Text Available Objetivou-se, no presente trabalho, a aplicação de β-1,3 glucanases e quitinases da linhagem Cellulosimicrobium cellulans 191 na lise de leveduras e inibição de fungos, respectivamente. O delineamento experimental mostrou que as melhores condições para a lise de Saccharomyces cerevisiae KL-88 pela β-1,3 glucanase foi pH 6,5 e 35ºC. As células de leveduras incubadas por 10 h em frascos sem agitação mostraram-se mais susceptíveis à lise pela ação da enzima. Foi obtido maior lise da levedura quando a suspensão de células foi submetida ao tratamento com β-1,3 glucanase e cisteína 1mM. A enzima invertase intracelular ou ligada à célula de S. cerevisiae KL-88 e K. marxianus NCYC 587 foi extraída após tratamento da suspensão celular com β-1,3 glucanase, sendo que o tratamento prévio das leveduras com a enzima aumentou a susceptibilidade das células à lise com ultra-som. A preparação de quitinase foi capaz de formar halos de inibição de alguns fungos.The aim of this work was the application of β-1,3 glucanases and chitinases by Cellulosimicrobium cellulans 191 strain on yeast cell lysis and fungi inhibition, respectively. The experimental design study showed that the best conditions to Saccharomyces cerevisiae KL-88 lysis by β-1,3 glucanase extract were pH 6,5 and 35ºC. This study also demonstrated that the yeast cells were more susceptible to lysis after 10 h of cultivation in flasks without agitation. Lysis activity was increased when S. cerevisiae KL-88 cell suspension was treated with β-1,3 glucanase and cystein 1mM. The enzyme invertase of S. cerevisiae KL-88 and Kluyveromyces marxianus NCYC 587 was extracted after treatment of cell suspension with β-1,3 glucanase and the previous treatment of yeasts with the enzyme, increased the susceptibility to lysis when ultrasonic treatment was used. The chitinase presented growth inhibition halos for some of the fungi.

  6. Lysis of autologous human macrophages by lymphokine-activated killer cells: interaction of effector cell and target cell conjugates analyzed by scanning electron microscopy.

    Science.gov (United States)

    Streck, R J; Helinski, E H; Ovak, G M; Pauly, J L

    1990-09-01

    Lymphokine (i.e., interleukin 2; IL-2)-activated killer (LAK) cells derived from normal human blood are known to destroy human tumor target cells. Accordingly, immunotherapy modalities using IL-2, either alone or in combination with LAK cells, have been evaluated for eradicating metastatic cancer. In studies conducted to characterize receptors on LAK cell membrane ultrastructures, we observed that LAK cells kill autologous human monocyte-derived macrophages (M phi). In these experiments, peripheral blood mononuclear cells of a healthy adult donor were cultured to generate LAK cells and autologous non-adherent M phi. Thereafter, conjugates were prepared by incubating for 3 h autologous populations of LAK cells and M phi. Examination of the conjugates by scanning electron microscopy (SEM) identified LAK cell-mediated killing of M phi. Moreover, SEM analysis of the LAK cell membrane architecture identified microvilli-like ultrastructures that provided a physical bridge that joined together the LAK cell and M phi. The immunological mechanism(s) underling LAK cell killing of autologous M phi is not known; nevertheless, these conjugates will provide a useful model to study membrane receptors on ultrastructures that mediate the initial stages of cytolysis that include target cell recognition and cell-to-cell adhesion. The results of our observations and the findings of other investigators who have also demonstrated LAK cell killing of autologous normal human leukocytes are discussed in the context of the association of IL-2 and IL-2-activated killer cells with side effects observed in ongoing clinical trials and with autoimmune disorders.

  7. Produção de protoplastos e lise da parede celular de leveduras utilizando β-1,3 glucanase Protoplasts production and yeast cell wall lysis using β-1,3 glucanase

    Directory of Open Access Journals (Sweden)

    Luciana Francisco Fleuri

    2010-06-01

    Full Text Available O presente trabalho visou a aplicação da β-1,3 glucanase lítica, obtida do microrganismo Cellulosimicrobium cellulans 191, na produção de protoplastos e na lise da parede celular de leveduras. A preparação bruta da enzima foi capaz de lisar as leveduras Kluyveromyces lodderi, Saccharomyces cerevisiae (Fleischmann e Itaiquara, S. cerevisiae KL-88, S. diastaticus NCYC 713, S. cerevisiae NCYC 1001, Candida glabrata NCYC 388, Kluyveromyces marxianus NCYC 587 e Hansenula mrakii NCYC 500. A β-1,3 glucanase purificada foi capaz de lisar as leveduras Saccharomyces cerevisiae KL-88, Saccharomyces capensis, Debaromyces vanriji, Pachysolen tannophillus, Kluyveromyces drosophilarum, Candida glabrata, Hansenula mrakii e Pichia membranaefaciens e formar protoplastos de Saccharomyces cerevisiae KL-88.The aim of this work was the application of lytic β-1,3 glucanase obtained from Cellulosimicrobium cellulans strain 191 in the production of protoplasts and lysis of yeast cell walls. The crude extract demonstrated lysis activity against the yeasts Kluyveromyces lodderi, Saccharomyces cerevisiae (Fleischmann and Itaiquara, S. cerevisiae KL-88, S. diastaticus NCYC 713, S. cerevisiae NCYC 1001, Candida glabrata NCYC 388, Kluyveromyces marxianus NCYC 587, and Hansenula mrakii NCYC 500. The purified β-1,3 glucanase demonstrated lysis activity against the yeasts Saccharomyces cerevisiae KL-88, Saccharomyces capensis, Debaromyces vanriji, Pachysolen tannophillus, Kluyveromyces drosophilarum, Candida glabrata, Hansenula mrakii, and Pichia membranaefaciens, and it was able to produce Saccharomyces cerevisiae KL-88 protoplasts.

  8. Evaluation of Lysis Methods for the Extraction of Bacterial DNA for Analysis of the Vaginal Microbiota.

    Directory of Open Access Journals (Sweden)

    Christina Gill

    Full Text Available Recent studies on the vaginal microbiota have employed molecular techniques such as 16S rRNA gene sequencing to describe the bacterial community as a whole. These techniques require the lysis of bacterial cells to release DNA before purification and PCR amplification of the 16S rRNA gene. Currently, methods for the lysis of bacterial cells are not standardised and there is potential for introducing bias into the results if some bacterial species are lysed less efficiently than others. This study aimed to compare the results of vaginal microbiota profiling using four different pretreatment methods for the lysis of bacterial samples (30 min of lysis with lysozyme, 16 hours of lysis with lysozyme, 60 min of lysis with a mixture of lysozyme, mutanolysin and lysostaphin and 30 min of lysis with lysozyme followed by bead beating prior to chemical and enzyme-based DNA extraction with a commercial kit.After extraction, DNA yield did not significantly differ between methods with the exception of lysis with lysozyme combined with bead beating which produced significantly lower yields when compared to lysis with the enzyme cocktail or 30 min lysis with lysozyme only. However, this did not result in a statistically significant difference in the observed alpha diversity of samples. The beta diversity (Bray-Curtis dissimilarity between different lysis methods was statistically significantly different, but this difference was small compared to differences between samples, and did not affect the grouping of samples with similar vaginal bacterial community structure by hierarchical clustering.An understanding of how laboratory methods affect the results of microbiota studies is vital in order to accurately interpret the results and make valid comparisons between studies. Our results indicate that the choice of lysis method does not prevent the detection of effects relating to the type of vaginal bacterial community one of the main outcome measures of

  9. Evaluation of Lysis Methods for the Extraction of Bacterial DNA for Analysis of the Vaginal Microbiota.

    Science.gov (United States)

    Gill, Christina; van de Wijgert, Janneke H H M; Blow, Frances; Darby, Alistair C

    2016-01-01

    Recent studies on the vaginal microbiota have employed molecular techniques such as 16S rRNA gene sequencing to describe the bacterial community as a whole. These techniques require the lysis of bacterial cells to release DNA before purification and PCR amplification of the 16S rRNA gene. Currently, methods for the lysis of bacterial cells are not standardised and there is potential for introducing bias into the results if some bacterial species are lysed less efficiently than others. This study aimed to compare the results of vaginal microbiota profiling using four different pretreatment methods for the lysis of bacterial samples (30 min of lysis with lysozyme, 16 hours of lysis with lysozyme, 60 min of lysis with a mixture of lysozyme, mutanolysin and lysostaphin and 30 min of lysis with lysozyme followed by bead beating) prior to chemical and enzyme-based DNA extraction with a commercial kit. After extraction, DNA yield did not significantly differ between methods with the exception of lysis with lysozyme combined with bead beating which produced significantly lower yields when compared to lysis with the enzyme cocktail or 30 min lysis with lysozyme only. However, this did not result in a statistically significant difference in the observed alpha diversity of samples. The beta diversity (Bray-Curtis dissimilarity) between different lysis methods was statistically significantly different, but this difference was small compared to differences between samples, and did not affect the grouping of samples with similar vaginal bacterial community structure by hierarchical clustering. An understanding of how laboratory methods affect the results of microbiota studies is vital in order to accurately interpret the results and make valid comparisons between studies. Our results indicate that the choice of lysis method does not prevent the detection of effects relating to the type of vaginal bacterial community one of the main outcome measures of epidemiological studies

  10. Antibacterial compounds of Canadian honeys target bacterial cell wall inducing phenotype changes, growth inhibition and cell lysis that resemble action of β-lactam antibiotics.

    Directory of Open Access Journals (Sweden)

    Katrina Brudzynski

    Full Text Available Honeys show a desirable broad spectrum activity against Gram-positive and negative bacteria making antibacterial activity an intrinsic property of honey and a desirable source for new drug development. The cellular targets and underlying mechanism of action of honey antibacterial compounds remain largely unknown. To facilitate the target discovery, we employed a method of phenotypic profiling by directly comparing morphological changes in Escherichia coli induced by honeys to that of ampicillin, the cell wall-active β-lactam of known mechanism of action. Firstly, we demonstrated the purity of tested honeys from potential β-lactam contaminations using quantitative LC-ESI-MS. Exposure of log-phase E. coli to honey or ampicillin resulted in time- and concentration-dependent changes in bacterial cell shape with the appearance of filamentous phenotypes at sub-inhibitory concentrations and spheroplasts at the MBC. Cell wall destruction by both agents, clearly visible on microscopic micrographs, was accompanied by increased permeability of the lipopolysaccharide outer membrane as indicated by fluorescence-activated cell sorting (FACS. More than 90% E. coli exposed to honey or ampicillin became permeable to propidium iodide. Consistently with the FACS results, both honey-treated and ampicillin-treated E. coli cells released lipopolysaccharide endotoxins at comparable levels, which were significantly higher than controls (p<0.0001. E. coli cells transformed with the ampicillin-resistance gene (β-lactamase remained sensitive to honey, displayed the same level of cytotoxicity, cell shape changes and endotoxin release as ampicillin-sensitive cells. As expected, β-lactamase protected the host cell from antibacterial action of ampicillin. Thus, both honey and ampicillin induced similar structural changes to the cell wall and LPS and that this ability underlies antibacterial activities of both agents. Since the cell wall is critical for cell growth and

  11. Rare incidence of tumor lysis syndrome in metastatic prostate cancer following treatment with docetaxel.

    Science.gov (United States)

    Bhardwaj, Sharonlin; Varma, Seema

    2018-03-01

    Tumor lysis syndrome is a serious and sometimes lethal complication of cancer treatment that is comprised of a set of metabolic disturbances along with clinical manifestations. Initiating chemotherapy in bulky, rapidly proliferating tumors causes rapid cell turnover that in turn releases metabolites into circulation that give rise to metabolic derangements that can be dangerous. This syndrome is usually seen in high-grade hematological malignancies. Less commonly, tumor lysis syndrome can present in solid tumors and even rarely in genitourinary tumors. In this report, the authors describe a specific case of tumor lysis syndrome in a patient with metastatic prostate cancer following treatment with docetaxel.

  12. Nucleation of holin domains and holes optimizes lysis timing of E. coli by phage λ

    Science.gov (United States)

    Ryan, Gillian; Rutenberg, Andrew

    2007-03-01

    Holin proteins regulate the precise scheduling of Escherichia coli lysis during infection by bacteriophage λ. Inserted into the host bacterium's inner membrane during infection, holins aggregate to form rafts and then holes within those rafts. We present a two-stage nucleation model of holin action, with the nucleation of condensed holin domains followed by the nucleation of holes within these domains. Late nucleation of holin rafts leads to a weak dependence of lysis timing on host cell size, though both nucleation events contribute equally to timing errors. Our simulations recover the accurate scheduling observed experimentally, and also suggest that phage-λ lysis of E.coli is optimized.

  13. Direct Cellular Lysis/Protein Extraction Protocol for Soil Metaproteomics

    Energy Technology Data Exchange (ETDEWEB)

    Chourey, Karuna [ORNL; Jansson, Janet [Lawrence Berkeley National Laboratory (LBNL); Verberkmoes, Nathan C [ORNL; Shah, Manesh B [ORNL; Chavarria, Krystle L. [Lawrence Berkeley National Laboratory (LBNL); Tom, Lauren M [Lawrence Berkeley National Laboratory (LBNL); Brodie, Eoin L. [Lawrence Berkeley National Laboratory (LBNL); Hettich, Robert {Bob} L [ORNL

    2010-01-01

    We present a novel direct protocol for deep proteome characterization of microorganisms in soil. The method employs thermally assisted detergent-based cellular lysis (SDS) of soil samples, followed by TCA precipitation for proteome extraction/cleanup prior to liquid chromatography-mass spectrometric characterization. This approach was developed and optimized using different soils inoculated with genome-sequenced bacteria (Gram-negative Pseudomonas putida or Gram-positive Arthrobacter chlorophenolicus). Direct soil protein extraction was compared to protein extraction from cells isolated from the soil matrix prior to lysis (indirect method). Each approach resulted in identification of greater than 500 unique proteins, with a wide range in molecular mass and functional categories. To our knowledge, this SDS-TCA approach enables the deepest proteome characterizations of microbes in soil to date, without significant biases in protein size, localization, or functional category compared to pure cultures. This protocol should provide a powerful tool for ecological studies of soil microbial communities.

  14. The Fc-receptor III of cultured human monocytes. Structural similarity with FcRIII of natural killer cells and role in the extracellular lysis of sensitized erythrocytes

    NARCIS (Netherlands)

    Klaassen, R. J.; Ouwehand, W. H.; Huizinga, T. W.; Engelfriet, C. P.; von dem Borne, A. E.

    1990-01-01

    FcRIII is not present on peripheral blood monocytes, but becomes expressed upon culturing and can be demonstrated on tissue macrophages. We studied the expression of FcRIII of cultured monocytes in detail and compared its structure with FcRIII of neutrophils and NK cells. The cell density of FcRIII

  15. Lysis of fresh human solid tumors by autologous lymphocytes activated in vitro with lectins

    International Nuclear Information System (INIS)

    Mazumder, A.; Grimm, E.A.; Zhang, H.Z.; Rosenberg, S.A.

    1982-01-01

    Human peripheral blood lymphocytes (PBL), obtained from patients with a variety of cancers, were incubated in vitro with phytohemagglutinin, concanavalin A, and crude or lectin-free T-cell growth factors. The lectin-activated PBL of nine patients were capable of lysing fresh autologous tumor during a 4-hr 51Cr release assay. Multiple metastases from the same patient were equivalently lysed by these activated autologous PBL. No lysis of fresh PBL or lectin-induced lymphoblast cell targets was seen, although tumor, PBL, and lymphoblast cells were shown to be equally lysable using allosensitized cells. The activated cells could be expanded without loss of cytotoxicity in crude or lectin-free T-cell growth factors. The generation of cells lytic to fresh autologous tumor was dependent on the presence of adherent cells, although the lytic cell itself was not adherent. Proliferation was not involved in the induction of lytic cells since equal lysis was induced in irradiated and nonirradiated lymphocytes. Lectin was not required in the lytic assay, and the addition of alpha-methyl-D-mannoside to concanavalin A-activated lymphoid cells did not increase the lysis of fresh tumor cells. Activation by lectin for 3 days appears to be an efficient and convenient method for generating human cells lytic to fresh autologous tumor. These lytic cells may be of value for studies of the cell-mediated lysis of human tumor and possibly for tumor immunotherapy as well

  16. Chimeric bispecific OC/TR monoclonal antibody mediates lysis of tumor cells expressing the folate-binding protein (MOv18) and displays decreased immunogenicity in patients

    NARCIS (Netherlands)

    Luiten, R. M.; Warnaar, S. O.; Sanborn, D.; Lamers, C. H.; Bolhuis, R. L.; Litvinov, S. V.; Zurawski, V. R.; Coney, L. R.

    1997-01-01

    The bispecific OC/TR monoclonal antibody (mAb) cross-links the CD3 molecule on T cells with the human folate-binding protein (FBP), which is highly expressed on nonmucinous ovarian carcinomas. Clinical trials of patients with ovarian carcinoma with the OC/TR mAb have shown some complete and partial

  17. Inactivation of the Autolysis-Related Genes lrgB and yycI in Staphylococcus aureus Increases Cell Lysis-Dependent eDNA Release and Enhances Biofilm Development In Vitro and In Vivo.

    Directory of Open Access Journals (Sweden)

    Cristiana Ossaille Beltrame

    Full Text Available Staphylococcus aureus ica-independent biofilms are multifactorial in nature, and various bacterial proteins have been associated with biofilm development, including fibronectin-binding proteins A and B, protein A, surface protein SasG, proteases, and some autolysins. The role of extracellular DNA (eDNA has also been demonstrated in some S. aureus biofilms. Here, we constructed a Tn551 library, and the screening identified two genes that affected biofilm formation, lrgB and yycI. The repressive effect of both genes on the development of biofilm was also confirmed in knockout strains constructed by allelic recombination. In contrast, the superexpression of either lrgB or yycI by a cadmium-inducible promoter led to a decrease in biofilm accumulation. Indeed, a significant increase in the cell-lysis dependent eDNA release was detected when lrgB or yycI were inactivated, explaining the enhanced biofilm formed by these mutants. In fact, lrgB and yycI genes belong to distinct operons that repress bacterial autolysis through very different mechanisms. LrgB is associated with the synthesis of phage holin/anti-holin analogues, while YycI participates in the activation/repression of the two-component system YycGF (WalKR. Our in vivo data suggest that autolysins activation lead to increased bacterial virulence in the foreign body animal model since a higher number of attached cells was recovered from the implanted catheters inoculated with lrgB or yycI knockout mutants.

  18. Comparison of Different Sample Preparation Protocols Reveals Lysis Buffer-Specific Extraction Biases in Gram-Negative Bacteria and Human Cells.

    Science.gov (United States)

    Glatter, Timo; Ahrné, Erik; Schmidt, Alexander

    2015-11-06

    We evaluated different in-solution and FASP-based sample preparation strategies for absolute protein quantification. Label-free quantification (LFQ) was employed to compare different sample preparation strategies in the bacterium Pseudomonas aeruginosa and human embryonic kidney cells (HEK), and organismal-specific differences in general performance and enrichment of specific protein classes were noted. The original FASP protocol globally enriched for most proteins in the bacterial sample, whereas the sodium deoxycholate in-solution strategy was more efficient with HEK cells. Although detergents were found to be highly suited for global proteome analysis, higher intensities were obtained for high-abundant nucleic acid-associated protein complexes, like the ribosome and histone proteins, using guanidine hydrochloride. Importantly, we show for the first time that the observable total proteome mass of a sample strongly depends on the sample preparation protocol, with some protocols resulting in a significant underestimation of protein mass due to incomplete protein extraction of biased protein groups. Furthermore, we demonstrate that some of the observed abundance biases can be overcome by incorporating a nuclease treatment step or, alternatively, a correction factor for complementary sample preparation approaches.

  19. A High Throughput Screening Assay for Anti-Mycobacterial Small Molecules Based on Adenylate Kinase Release as a Reporter of Cell Lysis.

    Directory of Open Access Journals (Sweden)

    Lauren Forbes

    Full Text Available Mycobacterium tuberculosis (Mtb is well-established to be one of the most important bacterial pathogens for which new antimicrobial therapies are needed. Herein, we describe the development of a high throughput screening assay for the identification of molecules that are bactericidal against Mycobacteria. The assay utilizes the release of the intracellular enzyme adenylate kinase into the culture medium as a reporter of mycobacterial cell death. We demonstrate that the assay is selective for mycobactericidal molecules and detects anti-mycobacterial activity at concentrations below the minimum inhibitory concentration of many molecules. Thus, the AK assay is more sensitive than traditional growth assays. We have validated the AK assay in the HTS setting using the Mtb surrogate organism M. smegmatis and libraries of FDA approved drugs as well as a commercially available Diversity set. The screen of the FDA-approved library demonstrated that the AK assay is able to identify the vast majority of drugs with known mycobactericidal activity. Importantly, our screen of the Diversity set revealed that the increased sensitivity of the AK assay increases the ability of M. smegmatis-based screens to detect molecules with relatively poor activity against M. smegmatis but good to excellent activity against Mtb.

  20. Increased Resistance to osmotic lysis of sickled erythrocytes ...

    African Journals Online (AJOL)

    treated with CNw had significantly reduced osmotic lysis when compared with the untreated set (P<0.05, respectively) at various hypotonic NaCl concentrations. Various Hb genotypes exhibited a graded increase in osmotic pressure lysis in ...

  1. Comprehensive Cross-Clade Characterization of Antibody-Mediated Recognition, Complement-Mediated Lysis, and Cell-Mediated Cytotoxicity of HIV-1 Envelope-Specific Antibodies toward Eradication of the HIV-1 Reservoir.

    Science.gov (United States)

    Mujib, Shariq; Liu, Jun; Rahman, A K M Nur-Ur; Schwartz, Jordan A; Bonner, Phil; Yue, Feng Yun; Ostrowski, Mario A

    2017-08-15

    Immunotherapy with passive administration of broadly neutralizing HIV-1 envelope-specific antibodies (bnAbs) in the setting of established infection in vivo has yielded mixed results. The contribution of different antibodies toward the direct elimination of infected cells is poorly understood. In this study, we determined the ability of 12 well-characterized anti-HIV-1 neutralizing antibodies to recognize and eliminate primary CD4 T cells infected with HIV-1 belonging to clades A, B, C, and D, via antibody-dependent complement-mediated lysis (ADCML) and antibody-dependent cell-mediated cytotoxicity (ADCC), in vitro We further tested unique combinations of these antibodies to determine the optimal antibody cocktails to be tested in future clinical trials. We report that antibody binding to infected CD4 T cells is highly variable and correlates with ADCML and ADCC processes. Particularly, antibodies targeting the envelope glycan shield (2G12) and V1/V2 site (PG9, PG16, and PGT145) are best at recognizing HIV-1-infected CD4 T cells. However, only PG9 and PG16 and their combinations with other bnAbs sufficiently induced the elimination of HIV-1-infected CD4 T cells by ADCML, ADCC, or both. Notably, CD4 binding site antibodies VRC01, 3BNC117, and NIH45-46 G54W did not exhibit recognition of infected cells and were unable to induce their killing. Future trials geared toward the development of a cure for HIV/AIDS should incorporate V1/V2 antibodies for maximal clearance of infected cells. With the use of only primary immune cells, we conducted a comprehensive cross-clade physiological analysis to aid the direction of antibodies as therapeutics toward the development of a cure for HIV/AIDS. IMPORTANCE Several antibodies capable of neutralizing the majority of circulating HIV-1 strains have been identified to date and have been shown to prevent infection in animal models. However, the use of combinations of such broadly neutralizing antibodies (bnAbs) for the treatment and

  2. Miniature acoustic wave lysis system and uses thereof

    Science.gov (United States)

    Branch, Darren W.; Vreeland, Erika Cooley; Smith, Gennifer Tanabe

    2016-12-06

    The present invention relates to an acoustic lysis system including a disposable cartridge that can be reversibly coupled to a platform having a small, high-frequency piezoelectric transducer array. In particular, the system releases viable DNA, RNA, and proteins from human or bacterial cells, without chemicals or additional processing, to enable high-speed sample preparation for clinical point-of-care medical diagnostics and use with nano/microfluidic cartridges. Also described herein are methods of making and using the system of the invention.

  3. Comparison of lysis-centrifugation with lysis-filtration and a conventional unvented bottle for blood cultures.

    OpenAIRE

    Gill, V J; Zierdt, C H; Wu, T C; Stock, F; Pizzo, P A; MacLowry, J D

    1984-01-01

    Evaluation of a commercially available lysis-centrifugation blood culture system (Isolator, DuPont Co., Wilmington, Del.) and a lysis-filtration blood culture system for 3,111 cultures showed that both methods had comparable recoveries (73 and 68%, respectively) of significant aerobic and facultatively anaerobic isolates. The unvented conventional blood culture bottle had a recovery rate of 59%. Although the lysis-centrifugation and lysis-filtration systems had comparable recoveries of pathog...

  4. Lysis-deficient phages as novel therapeutic agents for controlling bacterial infection

    Directory of Open Access Journals (Sweden)

    Kempashanaiah Nanjundappa

    2011-08-01

    Full Text Available Abstract Background Interest in phage therapy has grown over the past decade due to the rapid emergence of antibiotic resistance in bacterial pathogens. However, the use of bacteriophages for therapeutic purposes has raised concerns over the potential for immune response, rapid toxin release by the lytic action of phages, and difficulty in dose determination in clinical situations. A phage that kills the target cell but is incapable of host cell lysis would alleviate these concerns without compromising efficacy. Results We developed a recombinant lysis-deficient Staphylococcus aureus phage P954, in which the endolysin gene was rendered nonfunctional by insertional inactivation. P954, a temperate phage, was lysogenized in S. aureus strain RN4220. The native endolysin gene on the prophage was replaced with an endolysin gene disrupted by the chloramphenicol acetyl transferase (cat gene through homologous recombination using a plasmid construct. Lysogens carrying the recombinant phage were detected by growth in presence of chloramphenicol. Induction of the recombinant prophage did not result in host cell lysis, and the phage progeny were released by cell lysis with glass beads. The recombinant phage retained the endolysin-deficient genotype and formed plaques only when endolysin was supplemented. The host range of the recombinant phage was the same as that of the parent phage. To test the in vivo efficacy of the recombinant endolysin-deficient phage, immunocompromised mice were challenged with pathogenic S. aureus at a dose that results in 80% mortality (LD80. Treatment with the endolysin-deficient phage rescued mice from the fatal S. aureus infection. Conclusions A recombinant endolysin-deficient staphylococcal phage has been developed that is lethal to methicillin-resistant S. aureus without causing bacterial cell lysis. The phage was able to multiply in lytic mode utilizing a heterologous endolysin expressed from a plasmid in the propagation host

  5. Aggregate Formation During the Viral Lysis of a Marine Diatom

    Directory of Open Access Journals (Sweden)

    Yosuke Yamada

    2018-05-01

    Full Text Available Recent studies have suggested that the viral lysis of microbes not only facilitates the conversion of particulate organic matter into dissolved organic matter, but also promotes the formation of organic aggregates, which enhance the export of organic carbon from the surface ocean to the deep sea. However, experimental data supporting this proposition are limited. Here, we tested the hypothesis that the viral infection of marine diatoms enhances aggregate formation. We used a model system consisting of Chaetoceros tenuissimus, a bloom-forming diatom with an approximate cell size of 3–10 μm, and a DNA virus, CtenDNAV type II, which replicates in the nucleus of C. tenuissimus. The volume of large particles (50–400 μm in equivalent spherical diameters, determined from photographic images was measured over time (up to 15 days in the diatom-alone control and a virus-added diatom culture. We also determined the concentrations of Coomassie-stainable particles (CSP, proteinaceous particles and transparent exopolymeric particles (TEP, acid-polysaccharide-rich particles with colorimetric methods. The total volume of large particles was significantly higher (5–59 fold in the virus-added diatoms than in the diatom-alone control during the period in which the viral lysis of the diatoms proceeded. One class of large particles produced in the virus-added diatoms was flake-shaped. The flakes were tightly packed and dense, and sank rapidly, possibly playing an important role in the vertical delivery of materials from the surface to the deep sea. The bulk CSP concentrations tended to be higher in the virus-added diatoms than in the diatom-alone control, whereas the reverse was true for the TEP. These results suggest that proteinaceous polymers are involved in aggregate formation. Our data support the emerging notion that the viral lysis of microbes facilitates aggregate formation and the export of organic carbon in the ocean.

  6. Quantifying enzymatic lysis: estimating the combined effects of chemistry, physiology and physics

    International Nuclear Information System (INIS)

    Mitchell, Gabriel J; Weitz, Joshua S; Nelson, Daniel C

    2010-01-01

    The number of microbial pathogens resistant to antibiotics continues to increase even as the rate of discovery and approval of new antibiotic therapeutics steadily decreases. Many researchers have begun to investigate the therapeutic potential of naturally occurring lytic enzymes as an alternative to traditional antibiotics. However, direct characterization of lytic enzymes using techniques based on synthetic substrates is often difficult because lytic enzymes bind to the complex superstructure of intact cell walls. Here we present a new standard for the analysis of lytic enzymes based on turbidity assays which allow us to probe the dynamics of lysis without preparing a synthetic substrate. The challenge in the analysis of these assays is to infer the microscopic details of lysis from macroscopic turbidity data. We propose a model of enzymatic lysis that integrates the chemistry responsible for bond cleavage with the physical mechanisms leading to cell wall failure. We then present a solution to an inverse problem in which we estimate reaction rate constants and the heterogeneous susceptibility to lysis among target cells. We validate our model given simulated and experimental turbidity assays. The ability to estimate reaction rate constants for lytic enzymes will facilitate their biochemical characterization and development as antimicrobial therapeutics

  7. Quantifying enzymatic lysis: estimating the combined effects of chemistry, physiology and physics.

    Science.gov (United States)

    Mitchell, Gabriel J; Nelson, Daniel C; Weitz, Joshua S

    2010-10-04

    The number of microbial pathogens resistant to antibiotics continues to increase even as the rate of discovery and approval of new antibiotic therapeutics steadily decreases. Many researchers have begun to investigate the therapeutic potential of naturally occurring lytic enzymes as an alternative to traditional antibiotics. However, direct characterization of lytic enzymes using techniques based on synthetic substrates is often difficult because lytic enzymes bind to the complex superstructure of intact cell walls. Here we present a new standard for the analysis of lytic enzymes based on turbidity assays which allow us to probe the dynamics of lysis without preparing a synthetic substrate. The challenge in the analysis of these assays is to infer the microscopic details of lysis from macroscopic turbidity data. We propose a model of enzymatic lysis that integrates the chemistry responsible for bond cleavage with the physical mechanisms leading to cell wall failure. We then present a solution to an inverse problem in which we estimate reaction rate constants and the heterogeneous susceptibility to lysis among target cells. We validate our model given simulated and experimental turbidity assays. The ability to estimate reaction rate constants for lytic enzymes will facilitate their biochemical characterization and development as antimicrobial therapeutics.

  8. Lysis of typhus-group rickettsia-infected targets by lymphokine activated killers

    International Nuclear Information System (INIS)

    Carl, M.; Dasch, G.A.

    1986-01-01

    The authors recently described a subset of OKT8, OKT3-positive lymphocytes from typhus-group rickettsia immune individuals which were capable of lysing autologous PHA-blasts or Epstein-Barr virus transformed B cells (LCL) infected with typhus-group rickettsiae. In order to determine if killing by these effectors was HLA-restricted, they stimulated peripheral blood mononuclear cells (PBMC) from typhus-group rickettsia immune individuals in vitro with typhus-group rickettsia-derived antigen for one week and then measured lysis of autologous LCL or HLA-mismatched LCL in a 4-6 hour Cr 51 -release assay. There was significant lysis of both the autologous and the HLA-mismatched infected targets as compared to the corresponding uninfected targets. Since this suggested that the effectors were lymphokine activated killers (LAK) rather than cytotoxic T lymphocytes, they then tested this hypothesis by stimulating PBMC from both immune and non-immune individuals in vitro for one week with purified interleukin 2 and measuring lysis of infected, autologous LCL. PBMC thus treated, from both immune and non-immune individuals, were capable of significantly lysing autologous, infected LCL as compared to the non-infected control. They therefore conclude that targets infected with typhus-group rickettsiae are susceptible to lysis to LAK

  9. A mechanism of acquired resistance to complement-mediated lysis by Entamoeba histolytica.

    Science.gov (United States)

    Gutiérrez-Kobeh, L; Cabrera, N; Pérez-Montfort, R

    1997-04-01

    Some Entamoeba histolytica strains resist complement-mediated lysis by serum. Susceptible and resistant strains activate the complement system equivalently, but resistant amebas evade killing by membrane attack complexes. Our objective was to determine the mechanism by which trophozoites of E. histolytica resist lysis by human serum. Amebas were made resistant to lysis by incubation with increasing concentrations of normal human serum. The possibility that resistant cells ingest membrane attack complexes was explored by subcellular fractionation of susceptible and resistant trophozoites treated with sublytic concentrations of human serum containing radiolabeled C9. In both cases, most of the label was in the fractions containing plasma membrane. The susceptible strain consistently showed more label associated with these fractions than the resistant strain. Thus, the possibility that the membrane attack complexes were released to the medium was explored. Both resistant and susceptible trophozoites release to the medium similar amounts of material excluded by Sepharose CL-2B in the presence or absence of normal human serum. Labeled C9 elutes together with the main bulk of proteins from the medium: this indicates that it is not in vesicles or high molecular weight aggregates. Coincubation of susceptible amebas with lysates of resistant trophozoites confers resistance to susceptible cells within 30 min. Resistance to lysis by serum can also be acquired by susceptible amebas after coincubation with lysates from human erythrocytes or after feeding them with whole human red blood cells. Resistant but not susceptible trophozoites show intense immunofluorescent staining on their surface with anti-human erythrocytic membrane antibody. These results suggest that amebas acquire resistance to lysis by serum by incorporating into their membranes complement regulatory proteins.

  10. Virus-specific HLA-restricted lysis of herpes simplex virus-infected human monocytes and macrophages mediated by cytotoxic T lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Torpey, D.J. III

    1987-01-01

    Freshly-isolated peripheral blood human monocytes and 5 day in vitro cultured macrophages were infected with herpes simplex virus type 1 (HSV-1), labeled with /sup 51/Cr, and used as target cells in a 12-14 hour cell-mediated cytotoxicity assay. Mononuclear leukocytes (MNL) from HSV-1 non-immune individuals, whether unstimulated or stimulated with HSV-1 antigen, did not mediate significant lysis of either target cell. HSV-immune MNL, both freshly-isolated and cultured for 5 days without antigen, demonstrated only low levels of natural killer (NK) cell-mediate lysis. MNL from HSV-immune individuals incubated for 5 days in vitro with HSV-1 antigen mediated significant virus-specific lysis of both target cells. Mean virus-specific lysis of autologous monocytes was 8.5(/+-/2.0)% compared to a three-fold greater virus-specific lysis of autologous macrophages. Greater than 70% of this lytic activity was mediated by Leu-11-negative, T3-positive cytotoxic T lymphocytes (CTL). Allogeneic target cells lacking a common HLA determinant were not significantly lysed while T8-positive CTL mediated infrequent lysis of target cells sharing a common HLA-A and/or HLA-B determinant. T4-positive lymphocytes were demonstrated to be the predominant cell mediating lysis of autologous target cells and allogeneic target cells sharing both HLA-A and/or HLA-B plus HLA-DR determinants with the CTL; the T4-positive cell was the sole CTL mediator of lysis of allogeneic target cells having a common HLA-DR determinant.

  11. Virus-specific HLA-restricted lysis of herpes simplex virus-infected human monocytes and macrophages mediated by cytotoxic T lymphocytes

    International Nuclear Information System (INIS)

    Torpey, D.J. III.

    1987-01-01

    Freshly-isolated peripheral blood human monocytes and 5 day in vitro cultured macrophages were infected with herpes simplex virus type 1 (HSV-1), labeled with 51 Cr, and used as target cells in a 12-14 hour cell-mediated cytotoxicity assay. Mononuclear leukocytes (MNL) from HSV-1 non-immune individuals, whether unstimulated or stimulated with HSV-1 antigen, did not mediate significant lysis of either target cell. HSV-immune MNL, both freshly-isolated and cultured for 5 days without antigen, demonstrated only low levels of natural killer (NK) cell-mediate lysis. MNL from HSV-immune individuals incubated for 5 days in vitro with HSV-1 antigen mediated significant virus-specific lysis of both target cells. Mean virus-specific lysis of autologous monocytes was 8.5(/+-/2.0)% compared to a three-fold greater virus-specific lysis of autologous macrophages. Greater than 70% of this lytic activity was mediated by Leu-11-negative, T3-positive cytotoxic T lymphocytes (CTL). Allogeneic target cells lacking a common HLA determinant were not significantly lysed while T8-positive CTL mediated infrequent lysis of target cells sharing a common HLA-A and/or HLA-B determinant. T4-positive lymphocytes were demonstrated to be the predominant cell mediating lysis of autologous target cells and allogeneic target cells sharing both HLA-A and/or HLA-B plus HLA-DR determinants with the CTL; the T4-positive cell was the sole CTL mediator of lysis of allogeneic target cells having a common HLA-DR determinant

  12. 21 CFR 864.7275 - Euglobulin lysis time tests.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Euglobulin lysis time tests. 864.7275 Section 864.7275 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Kits and Packages § 864.7275 Euglobulin lysis...

  13. A self-lysis pathway that enhances the virulence of a pathogenic bacterium.

    Science.gov (United States)

    McFarland, Kirsty A; Dolben, Emily L; LeRoux, Michele; Kambara, Tracy K; Ramsey, Kathryn M; Kirkpatrick, Robin L; Mougous, Joseph D; Hogan, Deborah A; Dove, Simon L

    2015-07-07

    In mammalian cells, programmed cell death (PCD) plays important roles in development, in the removal of damaged cells, and in fighting bacterial infections. Although widespread among multicellular organisms, there are relatively few documented instances of PCD in bacteria. Here we describe a potential PCD pathway in Pseudomonas aeruginosa that enhances the ability of the bacterium to cause disease in a lung infection model. Activation of the system can occur in a subset of cells in response to DNA damage through cleavage of an essential transcription regulator we call AlpR. Cleavage of AlpR triggers a cell lysis program through de-repression of the alpA gene, which encodes a positive regulator that activates expression of the alpBCDE lysis cassette. Although this is lethal to the individual cell in which it occurs, we find it benefits the population as a whole during infection of a mammalian host. Thus, host and pathogen each may use PCD as a survival-promoting strategy. We suggest that activation of the Alp cell lysis pathway is a disease-enhancing response to bacterial DNA damage inflicted by the host immune system.

  14. Electrical lysis: dynamics revisited and advances in On-chip operation.

    Science.gov (United States)

    Morshed, Bashir; Shams, Maitham; Mussivand, Tofy

    2013-01-01

    Electrical lysis (EL) is the process of breaking the cell membrane to expose the internal contents under an applied high electric field. Lysis is an important phenomenon for cellular analysis, medical treatment, and biofouling control. This paper aims to review, summarize, and analyze recent advancements on EL. Major databases including PubMed, Ei Engineering Village, IEEE Xplore, and Scholars Portal were searched using relevant keywords. More than 50 articles published in English since 1997 are cited in this article. EL has several key advantages compared to other lysis techniques such as chemical, mechanical, sonication, or laser, including rapid speed of operation, ability to control, miniaturization, low cost, and low power requirement. A variety of cell types have been investigated for including protoplasts, E. coli, yeasts, blood cells, and cancer cells. EL has been developed and applied for decontamination, cytology, genetics, single-cell analysis, cancer treatment, and other applications. On-chip EL is a promising technology for multiplexed automated implementation of cell-sample preparation and processing with micro- or nanoliter reagents.

  15. Design and Modelling of a Microfluidic Electro-Lysis Device with Controlling Plates

    Science.gov (United States)

    Jenkins, A.; Chen, C. P.; Spearing, S.; Monaco, L. A.; Steele, A.; Flores, G.

    2006-04-01

    Many Lab-on-Chip applications require sample pre-treatment systems. Using electric fields to perform cell lysis in bio-MEMS systems has provided a powerful tool which can be integrated into Lab-on-a- Chip platforms. The major design considerations for electro-lysis devices include optimal geometry and placement of micro-electrodes, cell concentration, flow rates, optimal electric field (e.g. pulsed DC vs. AC), etc. To avoid electrolysis of the flowing solution at the exposed electrode surfaces, magnitudes and the applied voltages and duration of the DC pulse, or the AC frequency of the AC, have to be optimized for a given configuration. Using simulation tools for calculation of electric fields has proved very useful, for exploring alternative configurations and operating conditions for achieving electro cell-lysis. To alleviate the problem associated with low electric fields within the microfluidics channel and the high voltage demand on the contact electrode strips, two ''control plates'' are added to the microfluidics configuration. The principle of placing the two controlling plate-electrodes is based on the electric fields generated by a combined insulator/dielectric (glass/water) media. Surface charges are established at the insulator/dielectric interface. This paper discusses the effects of this interface charge on the modification of the electric field of the flowing liquid/cell solution.

  16. Study of the phage production efficiency in the bacteria lysis processes

    International Nuclear Information System (INIS)

    Vidania Munoz, R. de; Garces, F.; Davila, C. A.

    1979-01-01

    In this work we present a search for the best production conditions of λvir andλ clear phages In E coli K12 and E coli C 6 00 infected cells respectively. By keeping fixed some parameters of the process as the bacterial and phage generation times and (he bacterial burst side, we have finder that the lysis yield is strongly dependent on the multiplicity and in a lesser degree on the infection time. It appears from the experimental results that other variables are important, as infection efficiency and approach time from phages to bacteria. We will try to describe the lysis phenomenon by a numerical model on the bases of the se experimental results. (Author) 11 refs

  17. Role of the SRRz/Rz1 lambdoid lysis cassette in the pathoadaptive evolution of Shigella.

    Science.gov (United States)

    Leuzzi, Adriano; Grossi, Milena; Di Martino, Maria Letizia; Pasqua, Martina; Micheli, Gioacchino; Colonna, Bianca; Prosseda, Gianni

    2017-06-01

    Shigella, the etiological agent of bacillary dysentery (shigellosis), is a highly adapted human pathogen. It evolved from an innocuous ancestor resembling the Escherichia coli strain by gain and loss of genes and functions. While the gain process concerns the acquisition of the genetic determinants of virulence, the loss is related to the adaptation of the genome to the new pathogenic status and occurs by pathoadaptive mutation of antivirulence genes. In this study, we highlight that the SRRz/Rz 1 lambdoid lysis cassette, even though stably adopted in E. coli K12 by virtue of its beneficial effect on cell physiology, has undergone a significant decay in Shigella. Moreover, we show the antivirulence nature of the SRRz/Rz 1 lysis cassette in Shigella. In fact, by restoring the SRRz/Rz 1 expression in this pathogen, we observe an increased release of peptidoglycan fragments, causing an unbalance in the fine control exerted by Shigella on host innate immunity and a mitigation of its virulence. This strongly affects the virulence of Shigella and allows to consider the loss of SRRz/Rz 1 lysis cassette as another pathoadaptive event in the life of Shigella. Copyright © 2017 Elsevier GmbH. All rights reserved.

  18. Lysis of Gymnodinium breve by cultures of the green alga Nannochloris eucaryotum.

    Science.gov (United States)

    Pérez, E; Sawyers, W G; Martin, D F

    2001-01-01

    Laboratory cultures of Florida's red tide organism, Gymnodinium breve, were killed by the green alga Nannochloris eucaryotum. Studies involved organism-organism interaction as well as organism-cell-free culture (N. eucaryotum) interaction. Both studies demonstrated that N. eucaryotum adversely affected Florida's red tide organism. The lysis has been attributed to compounds called APONINs (apparent oceanic naturally occurring cytolins). N. eucaryotum crude APONIN was extracted from cell-free cultures, partially purified and fractionated. The fractions were bioassayed against G. breve, and 'fingerprints' of the deleterious fractions were obtained.

  19. Leukocyte Lysis and Cytokine Induction by the Human Sexually Transmitted Parasite Trichomonas vaginalis.

    Directory of Open Access Journals (Sweden)

    Frances Mercer

    2016-08-01

    Full Text Available Trichomonas vaginalis (Tv is an extracellular protozoan parasite that causes the most common non-viral sexually transmitted infection: trichomoniasis. While acute symptoms in women may include vaginitis, infections are often asymptomatic, but can persist and are associated with medical complications including increased HIV susceptibility, infertility, pre-term labor, and higher incidence of cervical cancer. Heightened inflammation resulting from Tv infection could account for these complications. Effective cellular immune responses to Tv have not been characterized, and re-infection is common, suggesting a dysfunctional adaptive immune response. Using primary human leukocyte components, we have established an in vitro co-culture system to assess the interaction between Tv and the cells of the human immune system. We determined that in vitro, Tv is able to lyse T-cells and B-cells, showing a preference for B-cells. We also found that Tv lysis of lymphocytes was mediated by contact-dependent and soluble factors. Tv lysis of monocytes is far less efficient, and almost entirely contact-dependent. Interestingly, a common symbiont of Tv, Mycoplasma hominis, did not affect cytolytic activity of the parasite, but had a major impact on cytokine responses. M. hominis enabled more diverse inflammatory cytokine secretion in response to Tv and, of the cytokines tested, Tv strains cleared of M. hominis induced only IL-8 secretion from monocytes. The quality of the adaptive immune response to Tv is therefore likely influenced by Tv symbionts, commensals, and concomitant infections, and may be further complicated by direct parasite lysis of effector immune cells.

  20. Leukocyte Lysis and Cytokine Induction by the Human Sexually Transmitted Parasite Trichomonas vaginalis

    Science.gov (United States)

    Mercer, Frances; Diala, Fitz Gerald I.; Chen, Yi-Pei; Molgora, Brenda M.; Ng, Shek Hang; Johnson, Patricia J.

    2016-01-01

    Trichomonas vaginalis (Tv) is an extracellular protozoan parasite that causes the most common non-viral sexually transmitted infection: trichomoniasis. While acute symptoms in women may include vaginitis, infections are often asymptomatic, but can persist and are associated with medical complications including increased HIV susceptibility, infertility, pre-term labor, and higher incidence of cervical cancer. Heightened inflammation resulting from Tv infection could account for these complications. Effective cellular immune responses to Tv have not been characterized, and re-infection is common, suggesting a dysfunctional adaptive immune response. Using primary human leukocyte components, we have established an in vitro co-culture system to assess the interaction between Tv and the cells of the human immune system. We determined that in vitro, Tv is able to lyse T-cells and B-cells, showing a preference for B-cells. We also found that Tv lysis of lymphocytes was mediated by contact-dependent and soluble factors. Tv lysis of monocytes is far less efficient, and almost entirely contact-dependent. Interestingly, a common symbiont of Tv, Mycoplasma hominis, did not affect cytolytic activity of the parasite, but had a major impact on cytokine responses. M. hominis enabled more diverse inflammatory cytokine secretion in response to Tv and, of the cytokines tested, Tv strains cleared of M. hominis induced only IL-8 secretion from monocytes. The quality of the adaptive immune response to Tv is therefore likely influenced by Tv symbionts, commensals, and concomitant infections, and may be further complicated by direct parasite lysis of effector immune cells. PMID:27529696

  1. Polymer Coatings in 3D-Printed Fluidic Device Channels for Improved Cellular Adherence Prior to Electrical Lysis.

    Science.gov (United States)

    Gross, Bethany C; Anderson, Kari B; Meisel, Jayda E; McNitt, Megan I; Spence, Dana M

    2015-06-16

    This paper describes the design and fabrication of a polyjet-based three-dimensional (3D)-printed fluidic device where poly(dimethylsiloxane) (PDMS) or polystyrene (PS) were used to coat the sides of a fluidic channel within the device to promote adhesion of an immobilized cell layer. The device was designed using computer-aided design software and converted into an .STL file prior to printing. The rigid, transparent material used in the printing process provides an optically transparent path to visualize endothelial cell adherence and supports integration of removable electrodes for electrical cell lysis in a specified portion of the channel (1 mm width × 0.8 mm height × 2 mm length). Through manipulation of channel geometry, a low-voltage power source (500 V max) was used to selectively lyse adhered endothelial cells in a tapered region of the channel. Cell viability was maintained on the device over a 5 day period (98% viable), though cell coverage decreased after day 4 with static media delivery. Optimal lysis potentials were obtained for the two fabricated device geometries, and selective cell clearance was achieved with cell lysis efficiencies of 94 and 96%. The bottleneck of unknown surface properties from proprietary resin use in fabricating 3D-printed materials is overcome through techniques to incorporate PDMS and PS.

  2. Inhibition of pneumococcal autolysis in lysis-centrifugation blood culture.

    OpenAIRE

    Lehtonen, O P

    1986-01-01

    The recovery of Streptococcus pneumoniae from the Isolator lysis-centrifugation blood culture has been low in many studies. The poor survival of pneumococci was not due to toxicity of the Isolator medium but to autolysis before plating. This autolysis was completely inhibited by adding 10 mM phosphorylcholine to the Isolator medium.

  3. Revisiting bistability in the lysis/lysogeny circuit of bacteriophage lambda.

    Directory of Open Access Journals (Sweden)

    Michael Bednarz

    Full Text Available The lysis/lysogeny switch of bacteriophage lambda serves as a paradigm for binary cell fate decision, long-term maintenance of cellular state and stimulus-triggered switching between states. In the literature, the system is often referred to as "bistable." However, it remains unclear whether this term provides an accurate description or is instead a misnomer. Here we address this question directly. We first quantify transcriptional regulation governing lysogenic maintenance using a single-cell fluorescence reporter. We then use the single-cell data to derive a stochastic theoretical model for the underlying regulatory network. We use the model to predict the steady states of the system and then validate these predictions experimentally. Specifically, a regime of bistability, and the resulting hysteretic behavior, are observed. Beyond the steady states, the theoretical model successfully predicts the kinetics of switching from lysogeny to lysis. Our results show how the physics-inspired concept of bistability can be reliably used to describe cellular phenotype, and how an experimentally-calibrated theoretical model can have accurate predictive power for cell-state switching.

  4. Tumor Lysis Syndrome (TLS following intrathecal chemotherapy in a child with acute myelogenous leukemia (AML

    Directory of Open Access Journals (Sweden)

    Chana L. Glasser, MD

    2017-01-01

    Full Text Available Tumor Lysis Syndrome (TLS is a well-known complication of induction therapy for hematologic malignancies. It is characterized by rapid breakdown of malignant white blood cells (WBCs leading to metabolic derangements and serious morbidity if left untreated. Most commonly, TLS is triggered by systemic chemotherapy, however, there have been case reports of TLS following intrathecal (IT chemotherapy, all in patients with acute lymphoblastic leukemia (ALL/lymphoma. Here, we report the first case of a patient with acute myelogenous leukemia (AML who developed TLS following a single dose of IT cytosine arabinoside (Ara-C.

  5. Sulfolobus turreted icosahedral virus c92 protein responsible for the formation of pyramid-like cellular lysis structures.

    Science.gov (United States)

    Snyder, Jamie C; Brumfield, Susan K; Peng, Nan; She, Qunxin; Young, Mark J

    2011-07-01

    Host cells infected by Sulfolobus turreted icosahedral virus (STIV) have been shown to produce unusual pyramid-like structures on the cell surface. These structures represent a virus-induced lysis mechanism that is present in Archaea and appears to be distinct from the holin/endolysin system described for DNA bacteriophages. This study investigated the STIV gene products required for pyramid formation in its host Sulfolobus solfataricus. Overexpression of STIV open reading frame (ORF) c92 in S. solfataricus alone is sufficient to produce the pyramid-like lysis structures in cells. Gene disruption of c92 within STIV demonstrates that c92 is an essential protein for virus replication. Immunolocalization of c92 shows that the protein is localized to the cellular membranes forming the pyramid-like structures.

  6. Sulfolobus Turreted Icosahedral Virus c92 Protein Responsible for the Formation of Pyramid-Like Cellular Lysis Structures

    DEFF Research Database (Denmark)

    Snyder, Jamie C; Brumfield, Susan K; Peng, Nan

    2011-01-01

    Host cells infected by Sulfolobus turreted icosahedral virus (STIV) have been shown to produce unusual pyramid-like structures on the cell surface. These structures represent a virus-induced lysis mechanism that is present in Archaea and appears to be distinct from the holin/endolysin system desc...... disruption of c92 within STIV demonstrates that c92 is an essential protein for virus replication. Immunolocalization of c92 shows that the protein is localized to the cellular membranes forming the pyramid-like structures.......Host cells infected by Sulfolobus turreted icosahedral virus (STIV) have been shown to produce unusual pyramid-like structures on the cell surface. These structures represent a virus-induced lysis mechanism that is present in Archaea and appears to be distinct from the holin/endolysin system...... described for DNA bacteriophages. This study investigated the STIV gene products required for pyramid formation in its host Sulfolobus solfataricus. Overexpression of STIV open reading frame (ORF) c92 in S. solfataricus alone is sufficient to produce the pyramid-like lysis structures in cells. Gene...

  7. Bacterial Infochemicals are Drivers of Algal Lysis

    Science.gov (United States)

    Whalen, K.; Deering, R.; Rowley, D. C.; El Gamal, A.; Schorn, M.; Moore, B. S.; Johnson, M. D.; Mincer, T. J.; Harvey, E.

    2016-02-01

    Processing of organic matter by bacteria forces oceanic biogeochemical cycles, food web structure and ultimately environmental stoichiometry. A newly emerging picture of the microbial loop suggests that bacteria are not merely passive recipients of dissolved organic matter (DOM) from phytoplankton exudate. Rather, heterotrophic bacteria can mediate the flow of DOM by actively producing soluble algicidal compounds. However, deciphering those chemical signals that determine these interactions has remained a challenge. Here, we report the isolation of 2-heptyl-4-quinolone (HHQ), released by Pseudoalteromonas piscicida, a marine gamma-proteobacteria isolated from plastic debris in the North Atlantic. Both 2-heptyl-3-hydroxy-4-quinolone and its immediate precursor, HHQ are known to function as antibiotics and quorum sensing signaling molecules with crucial roles in virulence, and apoptosis in eukaryotic cells (e.g. fungi and mammalian cells). Our ecologically-relevant screening of live cells and filtrate from P. piscicida cultures caused a significant decrease in the growth rate of the bloom-forming coccolithophore, Emiliania huxleyi. Bioassay-guided fraction of P. piscicida extracellular crude extracts identified HHQ, which induced mortality in three strains of E. huxleyi with an IC50 in the nanomolar range. In contrast, the marine chlorophyte, Dunaliella tertiolecta and diatom, Phaeodactylum tricornutum were unaffected by HHQ exposures (IC50 > 10 micromolar), but were susceptible to extracts of P. piscicida, indicating this bacterium may produce a cocktail of algicidal compounds specific to different phytoplankton guilds. The ability of HHQ to influence phytoplankton growth suggests that alkylquinolone-signaling molecules play a fundamental role in interkingdom interactions, ultimately influencing shifts in phytoplankton population dynamics. This study implicates a new role for HHQ beyond its importance in quorum sensing.

  8. Tumour lysis syndrome: A rare acute presentation of locally advanced testicular cancer – Case report and review of literature

    Directory of Open Access Journals (Sweden)

    Marcus Chow

    2016-01-01

    Full Text Available Tumour lysis syndrome (TLS is a potentially fatal complication of malignancy or its treatment. This uncommon syndrome comprises laboratory findings of hyperuricaemia, hypocalcaemia, hyperkalaemia and hyperphosphataemia. A literature search revealed a total of eight patients, with testicular cancer, who had TLS. All these patients had metastatic disease. We present a unique case of a 47-year-old gentleman we saw in clinic, who presented with a rapidly growing right groin mass and acute breathlessness, and discuss the diagnosis and management of TLS. TLS is extremely rare in testicular cancer but necessitates the awareness of urologists. TLS can occur spontaneously in testicular malignancy. Cell lysis in a rapidly proliferating germ cell tumour is a possible mechanism. The prompt identification and institution of management for TLS is crucial to improve clinical outcomes.

  9. Regulated programmed lysis of recombinant Salmonella in host tissues to release protective antigens and confer biological containment

    OpenAIRE

    Kong, Wei; Wanda, Soo-Young; Zhang, Xin; Bollen, Wendy; Tinge, Steven A.; Roland, Kenneth L.; Curtiss, Roy

    2008-01-01

    We have devised and constructed a biological containment system designed to cause programmed bacterial cell lysis with no survivors. We have validated this system, using Salmonella enterica serovar Typhimurium vaccines for antigen delivery after colonization of host lymphoid tissues. The system is composed of two parts. The first component is Salmonella typhimurium strain χ8937, with deletions of asdA and arabinose-regulated expression of murA, two genes required for peptidoglycan synthesis a...

  10. Clotrimazole enhances lysis of human erythrocytes induced by t-BHP.

    Science.gov (United States)

    Lisovskaya, Irene L; Shcherbachenko, Irina M; Volkova, Rimma I; Ataullakhanov, Fazoil I

    2009-08-14

    Clotrimazole (CLT) is an antifungal and antimalarial agent also effective as a Gardos channel inhibitor. In addition, CLT possesses antitumor properties. Recent data provide evidence that CLT forms a complex with heme (hemin), which produces a more potent lytic effect than heme alone. This study addressed the effect of CLT on the lysis of normal human erythrocytes induced by tert-butyl hydroperoxide (t-BHP). For the first time, it was shown that 10 microM CLT significantly enhanced the lytic effect of t-BHP on erythrocytes in both Ca(2+)-containing and Ca(2+)-free media, suggesting that the effect is not related to Gardos channels. CLT did not affect the rate of free radical generation, the kinetics of GSH degradation, methemoglobin formation and TBARS generation; therefore, we concluded that CLT does not cause additional oxidative damage to erythrocytes treated with t-BHP. It is tempted to speculate that CLT enhances t-BHP-induced changes in erythrocyte volume and lysis largely by forming a complex with hemin released during hemoglobin oxidation in erythrocytes: the CLT-hemin complex destabilizes the cell membrane more potently than hemin alone. If so, the effect of CLT on cell membrane damage during free-radical oxidation may be used to increase the efficacy of antitumor therapy.

  11. Dark membrane lysis and photosensitization by 3-carbethoxypsoralen

    Energy Technology Data Exchange (ETDEWEB)

    Muller-Runkel, R.; Grossweiner, L.I. (Illinois Inst. of Tech., Chicago (USA). Dept. of Physics)

    1981-03-01

    Aqueous solutions of 3-carbethoxypsoralen (3-CPs) induced lysis of egg lecithin liposomes and whole human erythrocytes in the dark. Near-UV irradiation of 3-CPs sensitized the inactivation of lysozyme attributed to the production of reactive radical intermediates. The implications of these findings for the use of 3-CPs as a sensitizer in psoralen + UV-A (PUVA) therapy of psoriasis are discussed.

  12. Dark membrane lysis and photosensitization by 3-carbethoxypsoralen

    International Nuclear Information System (INIS)

    Muller-Runkel, R.; Grossweiner, L.I.

    1981-01-01

    Aqueous solutions of 3-carbethoxypsoralen (3-CPs) induced lysis of egg lecithin liposomes and whole human erythrocytes in the dark. Near-UV irradiation of 3-CPs sensitized the inactivation of lysozyme attributed to the production of reactive radical intermediates. The implications of these findings for the use of 3-CPs as a sensitizer in psoralen + UV-A (PUVA) therapy of psoriasis are discussed. (author)

  13. RNA integrity as a quality indicator during the first steps of RNP purifications : A comparison of yeast lysis methods

    Directory of Open Access Journals (Sweden)

    Jansen Ralf-Peter

    2004-10-01

    Full Text Available Abstract Background The completion of several genome-sequencing projects has increased our need to assign functions to newly identified genes. The presence of a specific protein domain has been used as the determinant for suggesting a function for these new genes. In the case of proteins that are predicted to interact with mRNA, most RNAs bound by these proteins are still unknown. In yeast, several protocols for the identification of protein-protein interactions in high-throughput analyses have been developed during the last years leading to an increased understanding of cellular proteomics. If any of these protocols or similar approaches shall be used for the identification of mRNA-protein complexes, the integrity of mRNA is a critical factor. Results We compared the effect of different lysis protocols on RNA integrity. We report dramatic differences in RNA stability depending on the method used for yeast cell lysis. Glass bead milling and French Press lead to degraded mRNAs even in the presence of RNase inhibitors. Thus, they are not suitable to purify intact mRNP complexes or to identify specific mRNAs bound to proteins. Conclusion We suggest a novel protocol, grinding deep-frozen cells, for the preparation of protein extracts that contain intact RNAs, as lysis method for the purification of mRNA-protein complexes from yeast cells.

  14. NK cells and T cells: mirror images?

    NARCIS (Netherlands)

    Versteeg, R.

    1992-01-01

    The expression of MHC class I molecules protects cells against lysis by natural killer (NK) cells. It is possible that NK cells are 'educated' to recognize self MHC class I molecules and that the combination of self peptide and MHC class I molecule blocks NK-mediated lysis. Here, Rogier Versteeg

  15. A novel clot lysis assay for recombinant plasminogen activator.

    Science.gov (United States)

    Jamialahmadi, Oveis; Fazeli, Ahmad; Hashemi-Najafabadi, Sameereh; Fazeli, Mohammad Reza

    2015-03-01

    Recombinant plasminogen activator (r-PA, reteplase) is an engineered variant of alteplase. When expressed in E. coli, it appears as inclusion bodies that require refolding to recover its biological activity. An important step following refolding is to determine the activity of refolded protein. Current methods for enzymatic activity of thrombolytic drugs are costly and complex. Here a straightforward and low-cost clot lysis assay was developed. It quantitatively measures the activity of the commercial reteplase and is also capable of screening refolding conditions. As evidence for adequate accuracy and sensitivity of the current assay, r-PA activity measurements are shown to be comparable to those obtained from chromogenic substrate assay.

  16. Comparison of clot lysis activity and biochemical properties of originator tenecteplase (Metalyse® with those of an alleged biosimilar

    Directory of Open Access Journals (Sweden)

    Werner eKliche

    2014-02-01

    Full Text Available The bioengineered tissue plasminogen activator tenecteplase is an important treatment modality of acute myocardial infarction recommended by international guidelines. Following introduction of originator tenecteplase (brand names Metalyse® and TNKase®, a ‘biosimilar’ tenecteplase became available for commercial use in India under the brand name Elaxim® in the absence of Indian biosimilar guidelines which came into force from September 15th, 2012. Based on a report of biochemical and fibrinolytical differences between Metalyse and Elaxim, we have systematically compared them in a range of routine quality testing assays. As compared to Metalyse, Elaxim exhibited less clot lysis activity and contained less of the two-chain form of tenecteplase. Even upon full in vitro conversion to the two-chain form Elaxim exhibited less clot lysis activity. This was linked to differences in sialic acid content and glycosylation pattern with Elaxim exhibiting less bi- and more tetra-antennary glycosylation, leading to different charge heterogeneity profile. Regarding purity, Elaxim contained more tenecteplase aggregates and, in contrast to Metalyse, considerable amounts of Chinese hamster ovary cell protein. Taken together these data demonstrate that Metalyse and Elaxim differ considerably in clot lysis activity and biochemical properties. These data question whether Elaxim indeed can be considered a ‘biosimilar’ of Metalyse, i.e. whether and to which extent the clinical efficacy and safety properties of Metalyse can be extrapolated to Elaxim in the absence of comparative clinical data.

  17. A single lysis solution for the analysis of tissue samples by different proteomic technologies

    DEFF Research Database (Denmark)

    Gromov, P.; Celis, J.E.; Gromova, I.

    2008-01-01

    -based proteomics (reverse-phase lysate arrays or direct antibody arrays), allowing the direct comparison of qualitative and quantitative data yielded by these technologies when applied to the same samples. The usefulness of the CLB1 solution for gel-based proteomics was further established by 2D PAGE analysis...... dissease, is driving scientists to increasingly use clinically relevant samples for biomarker and target discovery. Tissues are heterogeneous and as a result optimization of sample preparation is critical for generating accurate, representative, and highly reproducible quantitative data. Although a large...... number of protocols for preparation of tissue lysates has been published, so far no single recipe is able to provide a "one-size fits all" solubilization procedure that can be used to analyse the same lysate using different proteomics technologies. Here we present evidence showing that cell lysis buffer...

  18. Lysis of Chlamydomonas reinhardtii by high-intensity focused ultrasound as a function of exposure time.

    Science.gov (United States)

    Bigelow, Timothy A; Xu, Jin; Stessman, Dan J; Yao, Linxing; Spalding, Martin H; Wang, Tong

    2014-05-01

    Efficient lysis of microalgae for lipid extraction is an important concern when processing biofuels. Historically, ultrasound frequencies in the range of 10-40 kHz have been utilized for this task. However, greater efficiencies might be achievable if higher frequencies could be used. In our study, we evaluated the potential of using 1.1 MHz ultrasound to lyse microalgae for biofuel production while using Chlamydomonas reinhardtii as a model organism. The ultrasound was generated using a spherically focused transducer with a focal length of 6.34 cm and an active diameter of 6.36 cm driven by 20 cycle sine-wave tone bursts at a pulse repetition frequency of 2 kHz (3.6% duty cycle). The time-average acoustic power output was 26.2 W while the spatial-peak-pulse-average intensity (ISPPA) for each tone burst was 41 kW/cm(2). The peak compressional and rarefactional pressures at the focus were 102 and 17 MPa, respectively. The exposure time was varied for the different cases in the experiments from 5s to 9 min and cell lysis was assessed by quantifying the percentage of protein and chlorophyll release into the supernate as well as the lipid extractability. Free radical generation and lipid oxidation for the different ultrasound exposures were also determined. We found that there was a statistically significant increase in lipid extractability for all of the exposures compared to the control. The longer exposures also completely fragmented the cells releasing almost all of the protein and chlorophyll into the supernate. The cavitation activity did not significantly increase lipid oxidation while there was a minor trend of increased free radical production with increased ultrasound exposure. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Role of adrenal hormones and prostaglandins in the control of mouse thymocytes lysis.

    Science.gov (United States)

    Durant, S; Seillan, C; Duval, D; Homo-Delarche, F

    1984-01-01

    The cytolytic actions of glucocorticoids and of agents increasing cyclic AMP were studied in vitro in thymocyte suspensions isolated from adrenalectomized or hydrocortisone-treated mice. Although considered as corticoresistant cells, the thymocytes isolated from hydrocortisone-treated mice were lysed to the same extent although more slowly in vitro by dexamethasone than whole thymocyte populations (i.e. corticosensitive cells). Moreover, these two cell populations were shown to contain comparable amounts of glucocorticoid receptors and to be almost equally sensitive to the metabolic effects of glucocorticoids when measured by inhibition of RNA and DNA synthesis. Studies performed with corticosensitive cells showed that prostaglandin E2, isoproterenol and dibutyrilcyclic AMP were also able to induce cell lysis and that, isoproterenol and dexamethasone exerted additive cytolytic action in vitro. In vivo experiments showed also an additive effect of steroids and isoproterenol on thymus atrophy. In contrast, cells isolated from hydrocortisone-treated animals were not sensitive to the cytotoxic action of prostaglandin E2, isoproterenol and dibutyril cyclic AMP. This difference between the two populations was not associated with any difference in the responsiveness of adenylate cyclase as determined following isoproterenol-induced accumulation of cyclic AMP. The cytolytic action of dexamethasone but also that of prostaglandin E2 and isoproterenol, could be blocked in the presence of cycloheximide, an inhibitor of protein synthesis, thus suggesting that glucocorticoids and agents increasing cyclic AMP control the synthesis of some proteins involved in the triggering of cell lysis. Among the hypotheses proposed to explain the differences between in vitro and in vivo sensitivity of lymphoid cell to glucocorticoids, it was suggested that the drug may in vivo indirectly control the viability or the proliferation of thymocytes through the release of other mediators. We have

  20. Isolation of Mycobacterium chelonei with the lysis-centrifugation blood culture technique.

    OpenAIRE

    Fojtasek, M F; Kelly, M T

    1982-01-01

    Mycobacterium chelonei was isolated from a patient by the lysis-centrifugation and the conventional two-bottle blood culture methods. The lysis-centrifugation method was significantly more sensitive and rapid than the conventional method in detecting and isolating this organism; quantitations done by this method were useful for monitoring response to therapy.

  1. Hyperphosphatemia during spontaneous tumor lysis syndrome culminate in severe hyphosphatemia at the time of blast crisis of Phneg CML to acute myelomoncytic leukemia

    Directory of Open Access Journals (Sweden)

    Salomon Ophira

    2012-08-01

    Full Text Available Abstract Extreme swing of phosphor from severe hyperphosphatemia to severe hypophosphatemia in a patient with blast crisis of myeloid origin was the result of imbalance between massive apoptosis of leukemic cells in the context of spontaneous tumor lysis syndrome and massive production of leukemic cells with only 1% of blast in peripheral blood. The mutated p53 protein suggested acting as oncogene in the presented case and possibly affecting phosphor status.

  2. Clot formation and lysis in platelet rich plasma of healthy donors and patients with resistant hypertension

    Directory of Open Access Journals (Sweden)

    I. I. Patalakh

    2018-04-01

    Full Text Available Hemostatic balance in blood is affected by numerous factors, including coagulation and fibrinolytic proteins, the wide spectrum of their inhibitors, and blood cells. Since platelets can participate in contradictory processes, they significantly complicate the whole picture. Therefore, nowadays the development of global assays of hemostasis, which can reflect the physiological process of hemostasis and can be used for point-of-care diagnosis of thrombosis, is crucial. This paper outlines a new approach we used to analyze the capabilities of clot waveform analysis tools to distinguish the response of platelet-rich plasma from healthy donors and patients with arterial hypertension caused by stimulation of coagulation and lysis (with exogenous thrombin and recombinant tissue-type plasminogen activator, respectively. In donor plasma, when the clot degradation was accompanied by 40 IU/ml of recombinant tissue-type plasminogen activator, platelets potentiated fibrinolysis more than coagulation, which ultimately shifts the overall balance to a profibrinolytic state. At the same time, for patients with hypertension, platelets, embedded in clot obtained from platelet-rich plasma, showed a weaker ability to stimulate fibrinolysis. The obtained data gives the evidence that platelets can act not only as procoagulants but also as profibrinolytics. By simultaneously amplifying coagulation and fibrinolysis, making their rates comparable, platelets would control plasma procoagulant activity, thereby regulating local hemostatic balance, the size and lifetime of the clot. Moreover, clot waveform analysis may be used to distinguish the effects of platelet-rich plasma on clotting or lysis of fibrin clots in healthy donors and patients with essential hypertension.

  3. Viral lysis of Phaeocystis pouchetii: implications for algal population dynamics and heterotrophic C, N and P cycling

    DEFF Research Database (Denmark)

    Haaber, Jakob Brandt Borup; Middelboe, Mathias

    2009-01-01

    in the microbial food web was associated with significant N and P mineralization, supporting the current view that viral lysates can be an important source of inorganic nutrients in marine systems. In the presence of R. salina, the generated NH(4)(+) supported 11% of the observed R. salina growth. Regrowth...... of virus-resistant P. pouchetii following cell lysis was observed in long-term incubations (150 days), and possibly influenced by nutrient availability and competition from R. salina. The observed impact of viral activity on autotrophic and heterotrophic processes provides direct experimental evidence...

  4. Tumor lysis syndrome in a patient with metastatic colon cancer after treatment with oxaliplatin and 5-Fu

    Directory of Open Access Journals (Sweden)

    Ruo-Han Tseng

    2016-12-01

    Full Text Available Tumor lysis syndrome in solid tumors is a rare occurrence, with a poor prognosis. We present the case of a patient of recurrent colon cancer who received chemotherapy with FOLFOX regimen (lencovorin, fluorouracil, and oxaliplatin with subsequent tumor lysis. We present a recurrent rectal cancer patient suffered from tumor lysis syndrome after salvage FOLFOX regimen. After treat with CVVH with improved conscious status. In this case report, we had review the tumor lysis in solid tumor.

  5. Application of Doehlert experimental design in the optimization of experimental variables for the Pseudozyma sp. (CCMB 306 and Pseudozyma sp. (CCMB 300 cell lysis Aplicação do modelo Doehlert na otimização das variáveis experimentais para a lise de Pseudozyma sp. (CCMB 306 e Pseudozyma sp. (CCMB 300

    Directory of Open Access Journals (Sweden)

    Amanda Reges de Sena

    2012-12-01

    Full Text Available This study aimed to verify the influence of pH and temperature on the lysis of yeast using experimental design. In this study, the enzymatic extract containing β-1,3-glucanase and chitinase, obtained from the micro-organism Moniliophthora perniciosa, was used. The experiment showed that the best conditions for lysis of Pseudozyma sp. (CCMB 306 and Pseudozyma sp. (CCMB 300 by lytic enzyme were pH 4.9 at 37 ºC and pH 3.9 at 26.7 ºC, respectively. The lytic enzyme may be used for obtaining various biotechnology products from yeast.O presente trabalho visou verificar a influência do pH e temperatura na lise de leveduras utilizando planejamento experimental. No estudo, foi utilizado o extrato enzimático, contendo β-1,3-glucanase e quitinase líticas, obtidas do micro-organismo Moniliophthora perniciosa. O delineamento experimental mostrou que as melhores condições para a lise de Pseudozyma sp. (CCMB 306 e Pseudozyma sp. (CCMB 300, pelas enzimas líticas, foram pH 4,9 a 37 ºC, pH 3,9 a 26,7 ºC, respectivamente. As enzimas líticas podem ser utilizadas para a obtenção de vários produtos biotecnológicos a partir de leveduras.

  6. Evaluation of conventional castaneda and lysis centrifugation blood culture techniques for diagnosis of human brucellosis.

    Science.gov (United States)

    Mantur, Basappa G; Mangalgi, Smita S

    2004-09-01

    We investigated the role of the lysis centrifugation blood culture technique over the conventional Castaneda technique for the diagnosis of human brucellosis. The lysis centrifugation technique has been found to be more sensitive in both acute (20% higher sensitivity; P centrifugation was in the mean detection time, which was only 2.4 days in acute and 2.7 days in chronic cases, with 103 out of 110 (93.6%) and 17 out of 20 (85%) cultures from acute and chronic brucellosis, respectively, detected before the conventional culture was positive. Our results confirmed the potential usefulness of the lysis technique in diagnosis and institution of appropriate antibiotic therapy.

  7. Leukocyte function-associated antigen-1-dependent lysis of Fas+ (CD95+/Apo-1+) innocent bystanders by antigen-specific CD8+ CTL.

    Science.gov (United States)

    Kojima, H; Eshima, K; Takayama, H; Sitkovsky, M V

    1997-09-15

    Exquisite specificity toward Ag-bearing cells (cognate targets) is one of the most important properties of CD8+ CTL-mediated cytotoxicity. Using highly Ag-specific CD8+ CTL lines and clones, which spare noncognate, Ag-free targets, we found that in the presence of Ag-bearing targets the CTL acquire the ability to lyse noncognate target cells (bystanders). It is shown that the unexpectedly rapid and efficient lysis of bystanders by Ag-activated CTL is mediated by a Fas ligand (FasL)/Fas-based mechanism and does not depend on perforin. The CTL lysed Fas-expressing bystanders, but spared the Fas-negative or anti-Fas mAb-resistant bystander cells. Accordingly, the FasL-deficient gld/gld CTL did not kill bystanders, while perforin-deficient CTL did. Unlike anti-Fas mAb-induced cell death, the lysis of bystanders was not only FasL/Fas dependent but also required adhesion molecule LFA-1 on the surface of the activated CTL. Lysis of bystanders is viewed as acceptable "collateral" damage, but the persistent presence of activated CTL could result in immunopathologies involving functional Fas-expressing tissues.

  8. Catheter placement for lysis of spontaneous intracerebral hematomas: does a catheter position in the core of the hematoma allow more effective and faster hematoma lysis?

    Science.gov (United States)

    Malinova, Vesna; Schlegel, Anna; Rohde, Veit; Mielke, Dorothee

    2017-07-01

    For the fibrinolytic therapy of intracerebral hematomas (ICH) using recombinant tissue plasminogen activator (rtPA), a catheter position in the core of the hematoma along the largest clot diameter was assumed to be optimal for an effective clot lysis. However, it never had been proven that core position indeed enhances clot lysis if compared with less optimal catheter positions. In this study, the impact of the catheter position on the effectiveness and on the time course of clot lysis was evaluated. We analyzed the catheter position using a relative error calculating the distance perpendicular to the catheter's center in relation to hematoma's diameter and evaluated the relative hematoma volume reduction (RVR). The correlation of the RVR with the catheter position was evaluated. Additionally, we tried to identify patterns of clot lysis with different catheter positions. The patient's outcome at discharge was evaluated using the Glasgow outcome score. A total of 105 patients were included in the study. The mean hematoma volume was 56 ml. The overall RVR was 62.7 %. In 69 patients, a catheter position in the core of the clot was achieved. We found no significant correlation between catheter position and hematoma RVR (linear regression, p = 0.14). Core catheter position leads to more symmetrical hematoma RVR. Faster clot lysis happens in the vicinity of the catheter openings. We found no significant difference in the patient's outcome dependent on the catheter position (linear regression, p = 0.90). The catheter position in the core of the hematoma along its largest diameter does not significantly influence the effectiveness of clot lysis after rtPA application.

  9. Mycobacterium tuberculosis bacteremia detected by the Isolator lysis-centrifugation blood culture system.

    OpenAIRE

    Kiehn, T E; Gold, J W; Brannon, P; Timberger, R J; Armstrong, D

    1985-01-01

    Mycobacterium tuberculosis was detected by the Isolator lysis-centrifugation blood culture system from the blood of a patient with tuberculosis of the breast. The organism also grew on conventional laboratory media inoculated with pleural fluid from the patient.

  10. Effects of copper, organic mercury and a mixture of the two on glycerol lysis of erythrocytes.

    OpenAIRE

    宮地,芳之

    1987-01-01

    The effects of copper, organic mercury and a mixture of the two on glycerol lysis of erythrocytes were examined. Copper ion and organic mercury (EMP; ethylmercury phosphate, and PCMB; sodium p-chloromercuricbenzoate) inhibited glycerol lysis of erythrocytes. The inhibitory effects was dependent on the incubation period. An equimolor solution of copper ion and EMP showed between copper ion and EMP. Similar results were obtained with copper and PCMB.

  11. Study of the phage production efficiency in the bacteria lysis processes; Estudio del rendimiento en fagos para los procesos de lisis bacteriana

    Energy Technology Data Exchange (ETDEWEB)

    Vidania Munoz, R de; Garces, F; Davila, C A

    1979-07-01

    In this work we present a search for the best production conditions of {lambda}vir and{lambda} clear phages In E coli K12 and E coli C{sub 6}00 infected cells respectively. By keeping fixed some parameters of the process as the bacterial and phage generation times and the bacterial burst side, we have found that the lysis yield is strongly dependent on the multiplicity and in a lesser degree on the infection time. It appears from the experimental results that other variables are important, as infection efficiency and approach time from phages to bacteria. We will try to describe the lysis phenomenon by a numerical model on the bases of the se experimental results. (Author) 11 refs.

  12. Studies on cytotoxic and clot lysis activity of probiotically fermented cocktail juice prepared using Camellia sinensis and Punica grantum

    Science.gov (United States)

    Biswas, Ananya; Deori, Meenakshi; Nivetha, A.; Mohansrinivasan, V.

    2017-11-01

    In the current research the effect of probiotic microorganisms viz; Lactococcus lactis and Lactobacillus plantarum on fermentation of Camellia sinensis and Punica grantum was studied. In vitro test were done to analyze the anticancer, antioxidant and atherosclerosis (clot lysis) properties of fermented juice. The juice was fermented for 48 and 96h, during which concentration of phenolic content, total acid content and free radical scavenging activity of the sample was analyzed by DPPH assay (α, α-diphenyl-β-picrylhydrazyl). Dropping of pH was observed after 48 h of fermentation. The clot lysis activity was found to be 80 % in 100μl concentration of fermented cocktail juice. The 96 h fermented sample has shown around 70% inhibition against colon cancer cell lines. Analytical study of HPLC proves the organic acid production such as ascorbic acid in superior amount for 96h of fermented sample, Based on the retention time, the corresponding peaks were detected at 4.919 and 4.831 min.

  13. Regulated programmed lysis of recombinant Salmonella in host tissues to release protective antigens and confer biological containment.

    Science.gov (United States)

    Kong, Wei; Wanda, Soo-Young; Zhang, Xin; Bollen, Wendy; Tinge, Steven A; Roland, Kenneth L; Curtiss, Roy

    2008-07-08

    We have devised and constructed a biological containment system designed to cause programmed bacterial cell lysis with no survivors. We have validated this system, using Salmonella enterica serovar Typhimurium vaccines for antigen delivery after colonization of host lymphoid tissues. The system is composed of two parts. The first component is Salmonella typhimurium strain chi8937, with deletions of asdA and arabinose-regulated expression of murA, two genes required for peptidoglycan synthesis and additional mutations to enhance complete lysis and antigen delivery. The second component is plasmid pYA3681, which encodes arabinose-regulated murA and asdA expression and C2-regulated synthesis of antisense asdA and murA mRNA transcribed from the P22 P(R) promoter. An arabinose-regulated c2 gene is present in the chromosome. chi8937(pYA3681) exhibits arabinose-dependent growth. Upon invasion of host tissues, an arabinose-free environment, transcription of asdA, murA, and c2 ceases, and concentrations of their gene products decrease because of cell division. The drop in C2 concentration results in activation of P(R), driving synthesis of antisense mRNA to block translation of any residual asdA and murA mRNA. A highly antigenic alpha-helical domain of Streptococcus pneumoniae Rx1 PspA was cloned into pYA3681, resulting in pYA3685 to test antigen delivery. Mice orally immunized with chi8937(pYA3685) developed antibody responses to PspA and Salmonella outer membrane proteins. No viable vaccine strain cells were detected in host tissues after 21 days. This system has potential applications with other Gram-negative bacteria in which biological containment would be desirable.

  14. Early postnatal diagnosis of hereditary spherocytosis by combining light microscopy, acidified glycerol lysis test and eosin-5'-maleimide binding assay.

    Science.gov (United States)

    Andres, Oliver; Eber, Stefan; Speer, Christian P

    2015-12-01

    Exact diagnosis of hereditary spherocytosis (HS) is widely considered unreliable around birth. However, early postnatal diagnosis at the beginning of congenital hemolysis may be essential for managing neonatal anemia and hemolytic icterus, identifying those at high risk for severe hyperbilirubinemia, irreversible kernicterus, or sudden need for red cell transfusion. We analyzed 37 blood samples from neonates or infants up to six weeks of life that had been collected in-house or shipped to our laboratory due to suspected red cell membrane disorder. By combining assessment of red cell morphology, acidified glycerol lysis test (AGLT), and eosin-5'-maleimide (EMA) binding assay, we were able to clearly exclude HS in 22 and confirm HS in 10 patients, of which one had undergone red cell transfusion prior to blood sampling. Assessment of red cell morphology and normal test results allowed diagnosis of infantile pyknocytosis or Heinz body anemia in three neonates. Re-evaluation of five patients with inconsistent results of AGLT and EMA binding led to confirmation of HS in two cases. Automated analysis of hematologic parameters revealed elevated proportion of hyperdense cells to be a highly significant indicator for HS in neonatal infants. We showed that assessment of red cell morphology in combination with AGLT and EMA binding assay is a reliable basis for confirming or rejecting suspected diagnosis of HS even in neonates. Our data underline the necessity for blood sampling and laboratory exploration in suspected red cell membrane or enzyme defects at the earliest occasion.

  15. Method and apparatus for iterative lysis and extraction of algae

    Science.gov (United States)

    Chew, Geoffrey; Boggs, Tabitha; Dykes, Jr., H. Waite H.; Doherty, Stephen J.

    2015-12-01

    A method and system for processing algae involves the use of an ionic liquid-containing clarified cell lysate to lyse algae cells. The resulting crude cell lysate may be clarified and subsequently used to lyse algae cells. The process may be repeated a number of times before a clarified lysate is separated into lipid and aqueous phases for further processing and/or purification of desired products.

  16. The euglobulin clot lysis time to assess the impact of nanoparticles on fibrinolysis

    Energy Technology Data Exchange (ETDEWEB)

    Minet, Valentine, E-mail: valentine.minet@unamur.be; Alpan, Lutfiye; Mullier, François [University of Namur – UNamur, Department of Pharmacy, Namur Thrombosis and Hemostasis Center (NTHC), Namur Nanosafety Center (NNC), NAmur Research Institute for Life Sciences NARILIS (Belgium); Toussaint, Olivier [Laboratory of Cellular Biochemistry and Biology (URBC) (Belgium); Lucas, Stéphane [University of Namur (UNamur), Research Centre for the Physics of Matter and Radiation (PMR-LARN), Namur Nanosafety Center NNC, NAmur Research Institute for Life Sciences NARILIS (Belgium); Dogné, Jean-Michel; Laloy, Julie, E-mail: julie.laloy@unamur.be [University of Namur – UNamur, Department of Pharmacy, Namur Thrombosis and Hemostasis Center (NTHC), Namur Nanosafety Center (NNC), NAmur Research Institute for Life Sciences NARILIS (Belgium)

    2015-07-15

    Nanoparticles (NPs) are developed for many applications in various fields, including nanomedicine. The NPs used in nanomedicine may disturb homeostasis in blood. Secondary hemostasis (blood coagulation) and fibrinolysis are complex physiological processes regulated by activators and inhibitors. An imbalance of this system can either lead to the development of hemorrhages or thrombosis. No data are currently available on the impact of NPs on fibrinolysis. The objectives of this study are (1) to select a screening test to study ex vivo the impact of NPs on fibrinolysis and (2) to test NPs with different physicochemical properties. Euglobulin clot lysis time test was selected to screen the impact of some NPs on fibrinolysis using normal pooled plasma. A dose-dependent decrease in the lysis time was observed with silicon dioxide and silver NPs without disturbing the fibrin network. Carbon black, silicon carbide, and copper oxide did not affect the lysis time at the tested concentrations.

  17. [Treatment of surface burns with proteolytic enzymes: mathematic description of lysis kinetics].

    Science.gov (United States)

    Domogatskaia, A S; Domogatskiĭ, S P; Ruuge, E K

    2003-01-01

    The lysis of necrotic tissue by a proteolytic enzyme applied to the surface of a burn wound was studied. A mathematical model was proposed, which describes changes in the thickness of necrotic tissue as a function of the proteolytic activity of the enzyme. The model takes into account the inward-directed diffusion of the enzyme, the counterflow of interstitial fluid (exudates) containing specific inhibitors, and the extracellular matrix proteolysis. It was shown in terms of the quasi-stationary approach that the thickness of the necrotic tissue layer decreases exponentially with time; i.e., the lysis slows down as the thickness of the necrotic tissue layer decreases. The dependence of the characteristic time of this decrease on enzyme concentration was obtained. It was shown that, at high enzyme concentrations (more than 5 mg/ml), the entire time of lysis (after the establishment of quasi-stationary equilibrium) is inversely proportional to the concentration of the enzyme.

  18. Tumor lysis syndrome following endoscopic radiofrequency interstitial thermal ablation of colorectal liver metastases.

    LENUS (Irish Health Repository)

    Barry, B D

    2012-02-03

    Radiofrequency interstitial thermal ablation (RITA) provides a palliative option for patients suffering from metastatic liver disease. This procedure can be performed using a laparoscopic approach with laparoscopic ultrasound used to position the RITA probe. We describe a case of laparoscopic RITA performed for colorectal liver metastasis that was complicated by tumor lysis syndrome (TLS) following treatment. We consider RITA to be a safe procedure, as supported by the literature, but where intracorporal tumor lysis is the treatment goal we believe that the systemic release of tumor products can overwhelm the excretory capacity; therefore, TLS is an inevitable consequence in some patients.

  19. Complement lysis activity in autologous plasma is associated with lower viral loads during the acute phase of HIV-1 infection.

    Directory of Open Access Journals (Sweden)

    Michael Huber

    2006-11-01

    Full Text Available BACKGROUND: To explore the possibility that antibody-mediated complement lysis contributes to viremia control in HIV-1 infection, we measured the activity of patient plasma in mediating complement lysis of autologous primary virus. METHODS AND FINDINGS: Sera from two groups of patients-25 with acute HIV-1 infection and 31 with chronic infection-were used in this study. We developed a novel real-time PCR-based assay strategy that allows reliable and sensitive quantification of virus lysis by complement. Plasma derived at the time of virus isolation induced complement lysis of the autologous virus isolate in the majority of patients. Overall lysis activity against the autologous virus and the heterologous primary virus strain JR-FL was higher at chronic disease stages than during the acute phase. Most strikingly, we found that plasma virus load levels during the acute but not the chronic infection phase correlated inversely with the autologous complement lysis activity. Antibody reactivity to the envelope (Env proteins gp120 and gp41 were positively correlated with the lysis activity against JR-FL, indicating that anti-Env responses mediated complement lysis. Neutralization and complement lysis activity against autologous viruses were not associated, suggesting that complement lysis is predominantly caused by non-neutralizing antibodies. CONCLUSIONS: Collectively our data provide evidence that antibody-mediated complement virion lysis develops rapidly and is effective early in the course of infection; thus it should be considered a parameter that, in concert with other immune functions, steers viremia control in vivo.

  20. TNF induction of EL4 hyposensitivity to lysis by recombinant (soluble) and membrane-associated TNFs: TNF binding, internalization, and degradation.

    Science.gov (United States)

    Fishman, M; Costlow, M

    1994-04-01

    EL4 mouse thymoma cells sensitive to TNF-mediated lysis only in the presence of cycloheximide (S-EL4) or in the presence or absence of cycloheximide (N-EL4) were used in these experiments. Murine tumor cell line (S-EL4) sensitivity to TNF cytotoxicity is augmented when cycloheximide is added together with TNF or when cycloheximide is added 1 hr before or after TNF. No enhanced sensitivity is observed when target cells are incubated with cycloheximide 2-4 hr before or after the addition of TNF. In the absence of cycloheximide, S-EL4 cells preexposed to murine TNF are less susceptible to lysis by TNF and TNF receptor-conjugated TNF but are lysed by integral membrane TNF. TNF-induced hyposensitivity is partially reversed by actinomycin D or by culturing the preexposed cells for 4 hr prior to TNF lytic assay. TNF preincubation of N- and S-EL4 cells results in an immediate decrease in 125I-TNF binding due to TNF receptor occupancy. Recovery of TNF-R occupancy and TNF internalization were subsequently noted.

  1. Viral lysis of photosynthesizing microbes as a mechanism for calcium carbonate nucleation in seawater

    Science.gov (United States)

    Lisle, John T.; Robbins, Lisa L.

    2016-01-01

    Removal of carbon through the precipitation and burial of calcium carbonate in marine sediments constitutes over 70% of the total carbon on Earth and is partitioned between coastal and pelagic zones. The precipitation of authigenic calcium carbonate in seawater, however, has been hotly debated because despite being in a supersaturated state, there is an absence of persistent precipitation. One of the explanations for this paradox is the geochemical conditions in seawater cannot overcome the activation energy barrier for the first step in any precipitation reaction; nucleation. Here we show that virally induced rupturing of photosynthetic cyanobacterial cells releases cytoplasmic-associated bicarbonate at concentrations ~23-fold greater than in the surrounding seawater, thereby shifting the carbonate chemistry toward the homogenous nucleation of one or more of the calcium carbonate polymorphs. Using geochemical reaction energetics, we show the saturation states (Ω) in typical seawater for calcite (Ω = 4.3), aragonite (Ω = 3.1), and vaterite (Ω = 1.2) are significantly elevated following the release and diffusion of the cytoplasmic bicarbonate (Ωcalcite = 95.7; Ωaragonite = 68.5; Ωvaterite = 25.9). These increases in Ω significantly reduce the activation energy for nuclei formation thresholds for all three polymorphs, but only vaterite nucleation is energetically favored. In the post-lysis seawater, vaterite's nuclei formation activation energy is significantly reduced from 1.85 × 10−17 J to 3.85 × 10−20 J, which increases the nuclei formation rate from highly improbable (nucleation of calcium carbonate in seawater describes a mechanism through which the initial step in the production of carbonate sediments may proceed. It also presents an additional role of photosynthesizing microbes and their viruses in marine carbon cycles and reveals these microorganisms are a collective repository for concentrated and reactive dissolved inorganic carbon (DIC

  2. Phenotypic variations in osmotic lysis of Sahel goat erythrocytes in non-ionic glucose media.

    Science.gov (United States)

    Igbokwe, Nanacha Afifi; Igbokwe, Ikechukwu Onyebuchi

    2016-03-01

    Erythrocyte osmotic lysis in deionised glucose media is regulated by glucose influx, cation efflux, and changes in cell volume after water diffusion. Transmembrane fluxes may be affected by varied expression of glucose transporter protein and susceptibility of membrane proteins to glucose-induced glycosylation and oxidation in various physiologic states. Variations in haemolysis of Sahel goat erythrocytes after incubation in hyposmotic non-ionic glucose media, associated with sex, age, late pregnancy, and lactation, were investigated. The osmotic fragility curve in glucose media was sigmoidal with erythrocytes from goats in late pregnancy (PRE) or lactation (LAC) or from kid (KGT) or middle-aged (MGT) goats. Non-sigmoidal phenotype occurred in yearlings (YGT) and old (OGT) goats. The composite fragility phenotype for males and non-pregnant dry (NPD) females was non-sigmoidal. Erythrocytes with non-sigmoidal curves were more stable than those with sigmoidal curves because of inflectional shift of the curve to the left. Erythrocytes tended to be more fragile with male than female sex, KGT and MGT than YGT and OGT, and LAC and PRE than NPD. Thus, sex, age, pregnancy, and lactation affected the haemolytic pattern of goat erythrocytes in glucose media. The physiologic state of the goat affected the in vitro interaction of glucose with erythrocytes, causing variations in osmotic stability with variants of fragility phenotype. Variations in the effect of high extracellular glucose concentrations on the functions of membrane-associated glucose transporter, aquaporins, and the cation cotransporter were presumed to be relevant in regulating the physical properties of goat erythrocytes under osmotic stress.

  3. Viral lysis of photosynthesizing microbes as a mechanism for calcium carbonate nucleation in seawater

    Science.gov (United States)

    Lisle, John T.; Robbins, Lisa L.

    2016-01-01

    Removal of carbon through the precipitation and burial of calcium carbonate in marine sediments constitutes over 70% of the total carbon on Earth and is partitioned between coastal and pelagic zones. The precipitation of authigenic calcium carbonate in seawater, however, has been hotly debated because despite being in a supersaturated state, there is an absence of persistent precipitation. One of the explanations for this paradox is the geochemical conditions in seawater cannot overcome the activation energy barrier for the first step in any precipitation reaction; nucleation. Here we show that virally induced rupturing of photosynthetic cyanobacterial cells releases cytoplasmic-associated bicarbonate at concentrations ~23-fold greater than in the surrounding seawater, thereby shifting the carbonate chemistry toward the homogenous nucleation of one or more of the calcium carbonate polymorphs. Using geochemical reaction energetics, we show the saturation states (Ω) in typical seawater for calcite (Ω = 4.3), aragonite (Ω = 3.1), and vaterite (Ω = 1.2) are significantly elevated following the release and diffusion of the cytoplasmic bicarbonate (Ωcalcite = 95.7; Ωaragonite = 68.5; Ωvaterite = 25.9). These increases in Ω significantly reduce the activation energy for nuclei formation thresholds for all three polymorphs, but only vaterite nucleation is energetically favored. In the post-lysis seawater, vaterite's nuclei formation activation energy is significantly reduced from 1.85 × 10−17 J to 3.85 × 10−20 J, which increases the nuclei formation rate from highly improbable (seawater describes a mechanism through which the initial step in the production of carbonate sediments may proceed. It also presents an additional role of photosynthesizing microbes and their viruses in marine carbon cycles and reveals these microorganisms are a collective repository for concentrated and reactive dissolved inorganic carbon (DIC) that is currently not accounted for

  4. Mechanisms of fever production and lysis: lessons from experimental LPS fever.

    Science.gov (United States)

    Roth, Joachim; Blatteis, Clark M

    2014-10-01

    Fever is a cardinal symptom of infectious or inflammatory insults, but it can also arise from noninfectious causes. The fever-inducing agent that has been used most frequently in experimental studies designed to characterize the physiological, immunological and neuroendocrine processes and to identify the neuronal circuits that underlie the manifestation of the febrile response is lipopolysaccharide (LPS). Our knowledge of the mechanisms of fever production and lysis is largely based on this model. Fever is usually initiated in the periphery of the challenged host by the immediate activation of the innate immune system by LPS, specifically of the complement (C) cascade and Toll-like receptors. The first results in the immediate generation of the C component C5a and the subsequent rapid production of prostaglandin E2 (PGE2). The second, occurring after some delay, induces the further production of PGE2 by induction of its synthesizing enzymes and transcription and translation of proinflammatory cytokines. The Kupffer cells (Kc) of the liver seem to be essential for these initial processes. The subsequent transfer of the pyrogenic message from the periphery to the brain is achieved by neuronal and humoral mechanisms. These pathways subserve the genesis of early (neuronal signals) and late (humoral signals) phases of the characteristically biphasic febrile response to LPS. During the course of fever, counterinflammatory factors, "endogenous antipyretics," are elaborated peripherally and centrally to limit fever in strength and duration. The multiple interacting pro- and antipyretic signals and their mechanistic effects that underlie endotoxic fever are the subjects of this review.

  5. Plasma Clot Lysis Time and Its Association with Cardiovascular Risk Factors in Black Africans

    NARCIS (Netherlands)

    Z. de Lange (Zelda); M. Pieters (Marlien); J.C. Jerling (Johann); A. Kruger (Annamarie); D.C. Rijken (Dingeman)

    2012-01-01

    textabstractStudies in populations of European descent show longer plasma clot lysis times (CLT) in patients with cardiovascular disease (CVD) than in controls. No data are available on the association between CVD risk factors and fibrinolytic potential in black Africans, a group undergoing rapid

  6. Changes in bacterial and eukaryotic community structure after mass lysis of filamentous cyanobacteria associated with viruses

    NARCIS (Netherlands)

    Hannen, E.J. van; Zwart, G.; Agterveld, M.P. van; Gons, H.J.; Ebert, J.; Laanbroek, H.J.

    1999-01-01

    During an experiment in two laboratory-scale enclosures filled with lake water (130 liters each) we noticed the almost-complete lysis of the cyanobacterial population. Based on electron microscopic observations of viral particles inside cyanobacterial filaments and counts of virus-like particles,

  7. Changes in bacterial and eukaryotic community structure after mass lysis of filamentous cyanobacteria associated with viruses

    NARCIS (Netherlands)

    Van Hannen, E.J.; Zwart, G.; Van Agterveld, M.P.; Gons, H.J.; Ebert, J.; Laanbroek, H.J.

    1999-01-01

    During an experiment in two laboratory-scale enclosures filled with lake water (130 liters each) we noticed the almost-complete lysis of the cyanobacterial population. Based on electron microscopic observations of viral particles inside cyanobacterial filaments and counts of virus-like particles, we

  8. Electrochemical lysis at the stage of endoresection for large posterior intraocular tumors

    Directory of Open Access Journals (Sweden)

    Yu. A. Belyy

    2012-01-01

    Full Text Available Purpose: to design the new combined technique of endoresection with intraoperative intraocular electrochemical lysis at the tumor destruction stage for large posterior intraocular tumors.Methods: 3 patients (3 eyes with large choroidal melanomas t3N0M0 (tumor thickness — 8-10 mm, base diameter — 13-15 mm, juxtapapillary localization. Mean age was 55.4 years old. Endoresection with intraoperational intraocular electrochemical lysis of the tumor was performed. Electrochemical lysis was performed with use of the technical unit ECU 300 (Soering, Germany and the original method of combined intratumoral positioning of two platinum electrodes: anode and cathode.Results: the tumor was removal completely in all 3 cases. the anatomical retinal reattachment was reached in all patients. Sclera was safe in all 3 cases. Visual acuity was not changed (NLP. At the place of the removal tumor a surgical choroidal coloboma without pigmentation all over scleral bed and periphery was shown in all cases in distant postoperative period (from 1.5 to 3 years. No local recurrences or metastasis were revealed in all patients.Conclusion: Further investigations in clinical group are necessarily to determinate the real possibilities of the combined method and the indications for endoresection with intraoperative intraocular electrochemical lysis for large intraocular tumors. 

  9. Influence of environmental variation on the bacterioplankton community and its loss to viral lysis in the Curonian Lagoon

    Science.gov (United States)

    Šulčius, Sigitas; Reunamo, Anna; Paškauskas, Ričardas; Leskinen, Piia

    2018-05-01

    Coastal lagoons are continuously exposed to strong environmental gradients that determine the distribution and trophic interactions of microbial communities. Therefore, in this study we assessed whether and how environmental changes influence the bacterial community and its vulnerability to viral infection and lysis along the major environmental gradient in the Curonian Lagoon. We found significant differences in bacterial community profiles, their richness and evenness between the riverine, freshwater southern part and the Baltic Sea water intrusion-influenced northern part of the lagoon, suggesting strong environmental control of the structure of bacterial communities. Viruses were found to be play an important role in bacterial mortality in the Curonian Lagoon, being responsible for the removal of 20-50% of the bacterial standing stock. We observed differences in virioplankton decay rates and virus burst sizes between the northern and southern parts of the lagoon. However, no relationships were found between viral activity and bacterial communities within the lagoon ecosystem. The frequency of infected cells and virus-mediated bacterial mortality (VMBM) remained constant among the sampling sites irrespective of differences in bacteria community assemblages and environmental conditions. The results indicate that factors determining changes in bacterial diversity are different from the factors limiting their vulnerability to viral infection and lysis. This study also suggests that under changing environmental conditions, virus-bacteria interactions are more stable than the interacting viral and bacterial communities themselves. These findings are important for understanding the functioning of the coastal ecosystems under the rapidly changing local (spatial and temporal) and global (e.g. eutrophication, climate change) conditions.

  10. CTL lysis: there is a hyperbolic relation of killing rate to exocytosable granzyme A for highly cytotoxic murine cytotoxic T lymphocytes.

    Science.gov (United States)

    Poe, M; Wu, J K; Talento, A; Koo, G C

    1996-06-10

    The lysis of susceptible targets by efficient cytotoxic T lymphocytes (CTL) increases both with time and with the ratio of CTL to target. Simple methods for calculating a killing rate constant from the time dependence of killing and for calculating the relation of the killing rate constant to the concentration of exocytosable granzyme A are given. Application of these methods to the killing of target cells by the highly efficient mouse CTL AR1 is presented. AR1 needed granzyme A for efficient killing. AR1 contained sufficient exocytosable granzyme A to kill at about 80% of the rate possible at infinite exocytosable granzyme A.

  11. Síndrome de lise tumoral: uma revisão abrangente da literatura Acute tumor lysis syndrome: a comprehensive review

    Directory of Open Access Journals (Sweden)

    Michael Darmon

    2008-09-01

    égias baseadas no risco dos pacientes são necessários para limitar a alta morbidade e mortalidade desta complicação.Tumor lysis syndrome is characterized by the massive destruction of malignant cells and the release in the extra-cellular space of their content. While Tumor lysis syndrome may occur spontaneously before treatment, it usually develops shortly after the initiation of cytotoxic chemotherapy. These metabolites can overwhelm the homeostatic mechanisms with development of hyperuricaemia, hyperkalaemia, hyperphosphataemia, and hypocalcaemia. These biological manifestations may lead to clinical manifestations including, acute kidney injury, seizure, or sudden death that require intensive care. Since clinical tumor lysis syndrome is associated with a poor prognosis both prevention of tumor lysis syndrome and prevention of clinical consequences of tumor lysis syndrome are mandatory. The objective of this review is to describe pathophysiological mechanisms, biological and clinical manifestations of tumor Lysis syndrome, and to provide upto-date guidelines to ensure prevention of tumor lysis syndrome. Review of selected studies on tumor lysis syndrome published at the PubMed database www.pubmed.gov during the last 20 years. Additional references were retrieved from the studies initially selected. Tumor lysis syndrome is a frequent and life-threatening complication of the newly diagnosed malignancies. Preventive measures, including hydration, uricolytic agents, eviction of factors predisposing to acute kidney injury and, in the more severe patients, on prophylactic renal replacement therapy, are required to prevent or limit clinical consequences of Tumor lysis syndrome. However optimal timing and modalities of prevention remains unknown and may be modified by the changing spectrum of patients at risk of tumor lysis syndrome. Development and validation of risk based strategies is required to limit the high morbidity and mortality of this complication.

  12. Controlled vesicle deformation and lysis by single oscillating bubbles

    Science.gov (United States)

    Marmottant, Philippe; Hilgenfeldt, Sascha

    2003-05-01

    The ability of collapsing (cavitating) bubbles to focus and concentrate energy, forces and stresses is at the root of phenomena such as cavitation damage, sonochemistry or sonoluminescence. In a biomedical context, ultrasound-driven microbubbles have been used to enhance contrast in ultrasonic images. The observation of bubble-enhanced sonoporation-acoustically induced rupture of membranes-has also opened up intriguing possibilities for the therapeutic application of sonoporation as an alternative to cell-wall permeation techniques such as electroporation and particle guns. However, these pioneering experiments have not been able to pinpoint the mechanism by which the violently collapsing bubble opens pores or larger holes in membranes. Here we present an experiment in which gentle (linear) bubble oscillations are sufficient to achieve rupture of lipid membranes. In this regime, the bubble dynamics and the ensuing sonoporation can be accurately controlled. The use of microbubbles as focusing agents makes acoustics on the micrometre scale (microacoustics) a viable tool, with possible applications in cell manipulation and cell-wall permeation as well as in microfluidic devices.

  13. Superiority of SDS lysis over saponin lysis for direct bacterial identification from positive blood culture bottle by MALDI-TOF MS.

    Science.gov (United States)

    Caspar, Yvan; Garnaud, Cécile; Raykova, Mariya; Bailly, Sébastien; Bidart, Marie; Maubon, Danièle

    2017-05-01

    Fast species diagnosis has an important health care impact, as rapid and specific antibacterial therapy is of clear benefit for patient's outcome. Here, a new protocol for species identification directly from positive blood cultures is proposed. Four in-house protocols for bacterial identification by MS directly from clinical positive blood cultures evaluating two lytic agents, SDS and saponin, and two protein extraction schemes, fast (FP) and long (LP) are compared. One hundred and sixty-eight identification tests are carried out on 42 strains. Overall, there are correct identifications to the species level in 90% samples for the SDS-LP, 60% for the SDS-FP, 48% for the saponin LP, and 43% for the saponin FP. Adapted scores allowed 92, 86, 72, and 53% identification for SDS-LP, SDS-FP, saponin LP, and saponin FP, respectively. Saponin lysis is associated with a significantly lower score compared to SDS (0.87 [0.83-0.92], p-value saponin lysis and the application of this rapid and cost-effective protocol in daily routine for microbiological agents implicated in septicemia. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. An improved in-house lysis-filtration protocol for bacterial identification from positive blood culture bottles with high identification rates by MALDI-TOF MS.

    Science.gov (United States)

    Tsuchida, Sachio; Murata, Syota; Miyabe, Akiko; Satoh, Mamoru; Takiwaki, Masaki; Matsushita, Kazuyuki; Nomura, Fumio

    2018-05-01

    Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is now a well-established method for identification of microorganisms from positive blood cultures. Pretreatments to effectively remove non-bacterial proteins are a prerequisite for successful identification, and a variety of protocols have been reported. Although commercially available kits, mainly the Sepsityper Kit, are increasingly used, the identification rates reported often are not satisfactory, particularly for Gram-positive isolates. We developed a new, in-house lysis-filtration protocol and prospectively evaluated its performance compared to the Sepsityper kit. The in-house protocol consists of three simple steps: lysis by ammonium chloride, aspiration with a syringe fitted with a 0.45-μm membrane, and centrifugation to collect microbes. The novel protocol requires only 20 min. Performance of the in-house protocol was evaluated using a total of 117 monomicrobial cases of positive blood culture. Medium from blood culture bottles was pretreated by the in-house protocol or the commercial kit, and isolated cells were subjected to direct identification by mass spectrometry fingerprinting in parallel with conventional subculturing for reference identification. The overall MALDI-TOF MS-based identification rates with score > 1.7 and > 2.0 obtained using the in-house protocol were 99.2% and 85.5%, respectively, whereas those obtained using the Sepsityper Kit were 85.4% and 61.5%, respectively. For Gram-positive cases, the in-house protocol yielded scores >1.7 and > 2.0 at 98.5% and 76.1%, respectively, whereas the commercial kit yielded these scores at 76.1% and 43.3%, respectively. Although these are preliminary results, these values suggest that this easy lysis-filtration protocol deserves assessment in a larger-scale test. Copyright © 2018 Elsevier B.V. All rights reserved.

  15. Spontaneous tumour lysis syndrome in a case of multiple myeloma – A rare occurrence

    Directory of Open Access Journals (Sweden)

    Kavitha Saravu

    2013-03-01

    Full Text Available We describe a case of a 40-year-old male patient who was found to have multiple myeloma with spontaneous tumour lysis syndrome (TLS, following a compression fracture of the L–2 vertebrae. Multiple myeloma was confirmed by bone marrow analysis and the M–band on serum protein electrophoresis. Hyperuricaemia (26.2 mg/dL, hyperkalaemia (> 7.0 mEq/L, hyperphosphatemia (16.2 mg of phosphorus/dL, normocalcemia and acute kidney injury, prior to anticancer treatment suggested spontaneous TLS. Inciting events for tumour lysis, such as chemotherapy, dehydration and exposure to steroids were absent. Patient received hydration, hypourecemic drugs and haemodialysis. This case report highlights the rare presentation of multiple myeloma with spontaneous TLS.

  16. A case of cetuximab-related tumour lysis syndrome in metastatic rectal carcinoma

    Science.gov (United States)

    Haroon, Muhammad; Kwong, Whye Yan; Cantwell, Brian; Walker, Frank

    2010-01-01

    A 60-year-old man was diagnosed with a moderately differentiated adenocarcinoma in November 2006. The computed tomography (CT), magnetic resonance imaging (MRI) and whole-body positron emission tomography–CT (PET–CT) scan showed the presence of multiple liver metastases which were confined to its right lobe. He had the first session of a combined therapy with cetuximab and 5-fluorouracil (5-FU) in March 2009; however, soon afterwards, he presented with the symptoms, signs and biochemistry suggestive of tumour lysis syndrome. Our unusual case highlights that tumour lysis syndrome can also develop in ‘low risk’ category tumours, and that clinicians should be vigilant in identifying at-risk patients. PMID:28657052

  17. [Intraoperative lysis and neurostimulation as added therapy in surgery of popliteal artery aneurysm].

    Science.gov (United States)

    Peiper, C; Heye, K; Ktenidis, K; Horsch, S

    1997-01-01

    Additional therapy of symptomatic popliteal artery aneurysm includes intraoperative lysis for the treatment of the descending thrombosis and spinal cord stimulation for cases of chronic deterioration of the peripheral perfusion state. Between 1989 and 1996, we treated 50 patients with 55 symptomatic aneurysms using this concept, 18 of them as emergency cases. We reached a postoperative amputation rate of 12.7% and good long-term functional results in 34 of 37 patients.

  18. Arthroscopic lysis and lavage in patients with temporomandibular anterior disc displacement without reduction

    Czech Academy of Sciences Publication Activity Database

    Machoň, V.; Šedý, Jiří; Klíma, K.; Hirjak, D.; Foltán, R.

    2012-01-01

    Roč. 41, č. 1 (2012), s. 109-113 ISSN 0901-5027 R&D Projects: GA MŠk(CZ) LC554; GA ČR GAP304/10/0320 Grant - others:GA MŠk(CZ) 1M0538 Program:1M Institutional research plan: CEZ:AV0Z50390703 Keywords : temporomandibular joint * arthroscopic lysis * arthroscopic lavage Subject RIV: FJ - Surgery incl. Transplants Impact factor: 1.521, year: 2012

  19. Comparison of the lysis-centrifugation and agitated biphasic blood culture systems for detection of fungemia.

    Science.gov (United States)

    Murray, P R

    1991-01-01

    Although the detection of fungemia has been improved by the use of vented or biphasic blood culture bottles, the best recovery and earliest detection have been reported in the Isolator lysis-centrifugation system. It was recently demonstrated that improved detection of both bacteria and fungi was accomplished by mechanically agitating blood culture bottles for the first 24 h of incubation. In this study the detection of fungemia by use of the Isolator system was compared with that of an agitated biphasic system. A total of 182 fungi were isolated from blood specimens inoculated into both culture systems. No difference in the overall recovery of fungi or individual species of yeasts was observed between the two systems. However, all seven isolates of Histoplasma capsulatum were recovered in the Isolator system only. The time required to detect fungemia with each of the two systems was also compared. No statistically significant difference was observed. From the data collected during this 18-month study, it can be concluded that the overall recovery and time of detection of yeasts are equivalent in the lysis-centrifugation system and the agitated biphasic blood culture system. The lysis-centrifugation system is still superior for the detection of filamentous fungi such as H. capsulatum. PMID:1993772

  20. Effect of ultrasonic frequency on the mechanism of formic acid sono-lysis

    International Nuclear Information System (INIS)

    Chave, T.; Nikitenko, S.I.; Navarro, N.M.; Pochon, P.; Bisel, I.

    2011-01-01

    The kinetics and mechanism of formic acid sono-chemical degradation were studied at ultrasonic frequencies of 20, 200, and 607 kHz under argon atmosphere. Total yield of HCOOH sono-chemical degradation increases approximately 6-8-fold when the frequency increased from 20 to 200 or to 607 kHz. At low ultrasonic frequencies, HCOOH degradation has been attributed to oxidation with OH . radicals from water sono-lysis and to the HCOOH decarboxylation occurring at the cavitation bubble-liquid interface. With high-frequency ultrasound, the sono-chemical reaction is also influenced by HCOOH dehydration. Whatever the ultrasonic frequency, the sono-lysis of HCOOH yielded H 2 and CO 2 in the gas phase as well as trace, amounts of oxalic acid and formaldehyde in the liquid phase. However, CO and CH 4 formations were only detected under high frequency ultrasound. The most striking difference between low frequency and high frequency ultrasound is that the sono-lysis of HCOOH at high ultrasonic frequencies initiates Fischer-Tropsch hydrogenation of carbon monoxide. (authors)

  1. STUDIES ON THE BACTERIOPHAGE OF D'HERELLE : IX. EVIDENCE OF HYDROLYSIS OF BACTERIAL PROTEIN DURING LYSIS.

    Science.gov (United States)

    Hetler, D M; Bronfenbrenner, J

    1928-07-31

    1. During the process of lysis by bacteriophage, there is an appreciable increase in the amount of free amino acid present in the culture. 2. The increase of free amino acid is due to hydrolysis of bacterial protein.

  2. Blood culture bottles are superior to lysis-centrifugation tubes for bacteriological diagnosis of spontaneous bacterial peritonitis.

    OpenAIRE

    Siersema, P D; de Marie, S; van Zeijl, J H; Bac, D J; Wilson, J H

    1992-01-01

    The conventional method of ascitic fluid culturing was compared with the bedside inoculation of ascites into blood culture bottles and into lysis-centrifugation tubes. The conventional culture method was compared with the blood culture bottle method in 31 episodes of spontaneous bacterial peritonitis (SBP). Cultures were positive with the conventional culture method in 11 (35%) episodes and with the blood culture bottle method in 26 (84%) episodes (P less than 0.001). The lysis-centrifugation...

  3. Chitinase and chitin synthase 1: counterbalancing activities in cell separation of Saccharomyces cerevisiae.

    Science.gov (United States)

    Cabib, E; Silverman, S J; Shaw, J A

    1992-01-01

    Previous results [E. Cabib, A. Sburlati, B. Bowers & S. J. Silverman (1989) Journal of Cell Biology 108, 1665-1672] strongly suggested that the lysis observed in daughter cells of Saccharomyces cerevisiae defective in chitin synthase 1 (Chs1) was caused by a chitinase that partially degrades the chitin septum in the process of cell separation. Consequently, it was proposed that in wild-type cells, Chs1 acts as a repair enzyme by replenishing chitin during cytokinesis. The chitinase requirement for lysis has been confirmed in two different ways: (a) demethylallosamidin, a more powerful chitinase inhibitor than the previously used allosamidin, is also a much better protector against lysis and (b) disruption of the chitinase gene in chs1 cells eliminates lysis. Reintroduction of a normal chitinase gene, by transformation of those cells with a suitable plasmid, restores lysis. The percentage of lysed cells in strains lacking Chs1 was not increased by elevating the chitinase level with high-copy-number plasmids carrying the hydrolase gene. Furthermore, the degree of lysis varied in different chs1 strains; lysis was abolished in chs1 mutants containing the scs1 suppressor. These results indicate that, in addition to chitinase, lysis requires other gene products that may become limiting.

  4. Surgical treatment of bilateral nondisplaced isthmic lysis by interlaminar fixation device

    Directory of Open Access Journals (Sweden)

    Keyvan Mostofi

    2017-01-01

    Full Text Available Study Design: Spondylolysis is a defect in the portion of pars interarticularis. The latter affects approximately 6% of the population. It is caused by repetitive trauma in hyperextension. Low back pain is the most common symptom. Methods: We implanted interspinous process devices in 12 patients with isthmic lysis without spondylolisthesis for low back pain. The purpose of the surgery was to conduct a minimally invasive procedure. Results: In eight cases, patients became asymptomatic. In two cases, there has been a considerable improvement. In two cases, no change had been noted. Conclusion: This good result motivates us to consider this approach a part of therapeutic arsenal for some cases of spondylolysis.

  5. Biological activity analysis of native and recombinant streptokinase using clot lysis and chromogenic substrate assay.

    Science.gov (United States)

    Mahboubi, Arash; Sadjady, Seyyed Kazem; Mirzaei Saleh Abadi, Mohammad; Azadi, Saeed; Solaimanian, Roya

    2012-01-01

    DETERMINATION OF STREPTOKINASE ACTIVITY IS USUALLY ACCOMPLISHED THROUGH TWO ASSAY METHODS: a) Clot lysis, b) Chromogenic substrate assay. In this study the biological activity of two streptokinase products, namely Streptase®, which is a native product and Heberkinasa®, which is a recombinant product, was determined against the third international reference standard using the two forementioned assay methods. The results indicated that whilst the activity of Streptase® was found to be 101 ± 4% and 97 ± 5% of the label claim with Clot lysis and Chromogenic substrate assay respectively, for Heberkinasa® the potency values obtained were 42 ± 5% and 92.5 ± 2% of the label claim respectively. To shed some light on the reason for this finding, the n-terminal sequence of the streptokinase molecules present in the two products was determined. The results showed slight differences in the amino acid sequence of the recombinant product in comparison to the native one at the amino terminus. This finding supports those of other workers who found that n-terminal sequence of the streptokinase molecule can have significant effect on the activity of this protein.

  6. Isolation and Expression of the Lysis Genes of Actinomyces naeslundii Phage Av-1

    Science.gov (United States)

    Delisle, Allan L.; Barcak, Gerard J.; Guo, Ming

    2006-01-01

    Like most gram-positive oral bacteria, Actinomyces naeslundii is resistant to salivary lysozyme and to most other lytic enzymes. We are interested in studying the lysins of phages of this important oral bacterium as potential diagnostic and therapeutic agents. To identify the Actinomyces phage genes encoding these species-specific enzymes in Escherichia coli, we constructed a new cloning vector, pAD330, that can be used to enrich for and isolate phage holin genes, which are located adjacent to the lysin genes in most phage genomes. Cloned holin insert sequences were used to design sequencing primers to identify nearby lysin genes by using whole phage DNA as the template. From partial digestions of A. naeslundii phage Av-1 genomic DNA we were able to clone, in independent experiments, inserts that complemented the defective λ holin in pAD330, as evidenced by extensive lysis after thermal induction. The DNA sequence of the inserts in these plasmids revealed that both contained the complete lysis region of Av-1, which is comprised of two holin-like genes, designated holA and holB, and an endolysin gene, designated lysA. We were able to subclone and express these genes and determine some of the functional properties of their gene products. PMID:16461656

  7. Analysis of five streptokinase formulations using the euglobulin lysis test and the plasminogen activation assay

    Directory of Open Access Journals (Sweden)

    Couto L.T.

    2004-01-01

    Full Text Available Streptokinase, a 47-kDa protein isolated and secreted by most group A, C and G ß-hemolytic streptococci, interacts with and activates human protein plasminogen to form an active complex capable of converting other plasminogen molecules to plasmin. Our objective was to compare five streptokinase formulations commercially available in Brazil in terms of their activity in the in vitro tests of euglobulin clot formation and of the hydrolysis of the plasmin-specific substrate S-2251(TM. Euglobulin lysis time was determined using a 96-well microtiter plate. Initially, human thrombin (10 IU/ml and streptokinase were placed in individual wells, clot formation was initiated by the addition of plasma euglobulin, and turbidity was measured at 340 nm every 30 s. In the second assay, plasminogen activation was measured using the plasmin-specific substrate S-2251(TM. Streptase(TM was used as the reference formulation because it presented the strongest fibrinolytic activity in the euglobulin lysis test. The Unitinase(TM and Solustrep(TM formulations were the weakest, showing about 50% activity compared to the reference formulation. All streptokinases tested activated plasminogen but significant differences were observed. In terms of total S-2251(TM activity per vial, Streptase(TM (75.7 ± 5.0 units and Streptonase(TM (94.7 ± 4.6 units had the highest activity, while Unitinase(TM (31.0 ± 2.4 units and Strek(TM (32.9 ± 3.3 units had the weakest activity. Solustrep(TM (53.3 ± 2.7 units presented intermediate activity. The variations among the different formulations for both euglobulin lysis test and chromogenic substrate hydrolysis correlated with the SDS-PAGE densitometric results for the amount of 47-kDa protein. These data show that the commercially available clinical streptokinase formulations vary significantly in their in vitro activity. Whether these differences have clinical implications needs to be investigated.

  8. Prediction of recurrent venous thromboembolism by clot lysis time: a prospective cohort study.

    Science.gov (United States)

    Traby, Ludwig; Kollars, Marietta; Eischer, Lisbeth; Eichinger, Sabine; Kyrle, Paul A

    2012-01-01

    Venous thromboembolism (VTE) is a chronic disease, which tends to recur. Whether an abnormal fibrinolytic system is associated with an increased risk of VTE is unclear. We assessed the relationship between fibrinolytic capacity (reflected by clot lysis time [CLT]) and risk of recurrent VTE. We followed 704 patients (378 women; mean age 48 yrs) with a first unprovoked VTE for an average of 46 months after anticoagulation withdrawal. Patients with natural coagulation inhibitor deficiency, lupus anticoagulant, cancer, homozygosity for factor V Leiden or prothrombin mutation, or requirement for indefinite anticoagulation were excluded. Study endpoint was symptomatic recurrent VTE. For measurement of CLT, a tissue factor-induced clot was lysed by adding tissue-type plasminogen activator. Time between clot formation and lysis was determined by measuring the turbidity. 135 (19%) patients had recurrent VTE. For each increase in CLT of 10 minutes, the crude relative risk (RR) of recurrence was 1.13 (95% CI 1.02-1.25; p = 0.02) and was 1.08 (95% CI 0.98-1.20; p = 0.13) after adjustment for age and sex. For women only, the adjusted RR was 1.14 (95% CI, 0.91-1.42, p = 0.22) for each increase in CLT of 10 minutes. CLT values in the 4(th) quartile of the female patient population, as compared to values in the 1(st) quartile, conferred a risk of recurrence of 3.28 (95% CI, 1.07-10.05; p = 0.04). No association between CLT and recurrence risk was found in men. Hypofibrinolysis as assessed by CLT confers a moderate increase in the risk of recurrent VTE. A weak association between CLT and risk of recurrence was found in women only.

  9. Prediction of recurrent venous thromboembolism by clot lysis time: a prospective cohort study.

    Directory of Open Access Journals (Sweden)

    Ludwig Traby

    Full Text Available Venous thromboembolism (VTE is a chronic disease, which tends to recur. Whether an abnormal fibrinolytic system is associated with an increased risk of VTE is unclear. We assessed the relationship between fibrinolytic capacity (reflected by clot lysis time [CLT] and risk of recurrent VTE. We followed 704 patients (378 women; mean age 48 yrs with a first unprovoked VTE for an average of 46 months after anticoagulation withdrawal. Patients with natural coagulation inhibitor deficiency, lupus anticoagulant, cancer, homozygosity for factor V Leiden or prothrombin mutation, or requirement for indefinite anticoagulation were excluded. Study endpoint was symptomatic recurrent VTE. For measurement of CLT, a tissue factor-induced clot was lysed by adding tissue-type plasminogen activator. Time between clot formation and lysis was determined by measuring the turbidity. 135 (19% patients had recurrent VTE. For each increase in CLT of 10 minutes, the crude relative risk (RR of recurrence was 1.13 (95% CI 1.02-1.25; p = 0.02 and was 1.08 (95% CI 0.98-1.20; p = 0.13 after adjustment for age and sex. For women only, the adjusted RR was 1.14 (95% CI, 0.91-1.42, p = 0.22 for each increase in CLT of 10 minutes. CLT values in the 4(th quartile of the female patient population, as compared to values in the 1(st quartile, conferred a risk of recurrence of 3.28 (95% CI, 1.07-10.05; p = 0.04. No association between CLT and recurrence risk was found in men. Hypofibrinolysis as assessed by CLT confers a moderate increase in the risk of recurrent VTE. A weak association between CLT and risk of recurrence was found in women only.

  10. Biological variation in tPA-induced plasma clot lysis time.

    Science.gov (United States)

    Talens, Simone; Malfliet, Joyce J M C; Rudež, Goran; Spronk, Henri M H; Janssen, Nicole A H; Meijer, Piet; Kluft, Cornelis; de Maat, Moniek P M; Rijken, Dingeman C

    2012-10-01

    Hypofibrinolysis is a risk factor for venous and arterial thrombosis, and can be assessed by using a turbidimetric tPA-induced clot lysis time (CLT) assay. Biological variation in clot lysis time may affect the interpretation and usefulness of CLT as a risk factor for thrombosis. Sufficient information about assay variation and biological variation in CLT is not yet available. Thus, this study aimed to determine the analytical, within-subject and between-subject variation in CLT. We collected blood samples from 40 healthy individuals throughout a period of one year (average 11.8 visits) and determined the CLT of each plasma sample in duplicate. The mean (± SD) CLT was 83.8 (± 11.1) minutes. The coefficients of variation for total variation, analytical variation, within-subject variation and between-subject variation were 13.4%, 2.6%, 8.2% and 10.2%, respectively. One measurement can estimate the CLT that does not deviate more than 20% from its true value. The contribution of analytical variation to the within-subject variation was 5.0%, the index of individuality was 0.84 and the reference change value was 23.8%. The CLT was longer in the morning compared to the afternoon and was slightly longer in older individuals (> 40 years) compared to younger (≤40 years) individuals. There was no seasonal variation in CLT and no association with air pollution. CLT correlated weakly with fibrinogen, C-reactive protein, prothrombin time and thrombin generation. This study provides insight into the biological variation of CLT, which can be used in future studies testing CLT as a potential risk factor for thrombosis.

  11. A new apparatus to induce lysis of planktonic microbial cells by shock compression, cavitation and spray

    Science.gov (United States)

    Schiffer, A.; Gardner, M. N.; Lynn, R. H.; Tagarielli, V. L.

    2017-03-01

    Experiments were conducted on an aqueous growth medium containing cultures of Escherichia coli (E. coli) XL1-Blue, to investigate, in a single experiment, the effect of two types of dynamic mechanical loading on cellular integrity. A bespoke shock tube was used to subject separate portions of a planktonic bacterial culture to two different loading sequences: (i) shock compression followed by cavitation, and (ii) shock compression followed by spray. The apparatus allows the generation of an adjustable loading shock wave of magnitude up to 300 MPa in a sterile laboratory environment. Cultures of E. coli were tested with this apparatus and the spread-plate technique was used to measure the survivability after mechanical loading. The loading sequence (ii) gave higher mortality than (i), suggesting that the bacteria are more vulnerable to shear deformation and cavitation than to hydrostatic compression. We present the results of preliminary experiments and suggestions for further experimental work; we discuss the potential applications of this technique to sterilize large volumes of fluid samples.

  12. Role of cell surface composition and lysis in static biofilm formation by Lactobacillus plantarum WCFS1

    NARCIS (Netherlands)

    Fernández Ramírez, Mónica D.; Nierop Groot, Masja N.; Smid, Eddy J.; Hols, Pascal; Kleerebezem, Michiel; Abee, Tjakko

    2018-01-01

    Next to applications in fermentations, Lactobacillus plantarum is recognized as a food spoilage organism, and its dispersal from biofilms in food processing environments might be implicated in contamination or recontamination of food products. This study provides new insights into biofilm

  13. Study on improvement of sludge dewaterability with H2O2 cell lysis

    Science.gov (United States)

    Zhuo, Qiongfang; Yi, Hao; Zhang, Zhengke; Wang, Ji; Feng, Lishi; Xu, Zhencheng; Guo, Qingwei; Jin, Zhong; Lan, Yongzhe

    2017-12-01

    Excess sludge is the product of sewage treatment plants. With continuous perfection of municipal sewage treatment facilities in China, sludge output increases as a result of the growth of sewage treatment plants. Excess sludge has complicated compositions, including heavy metals, PPCPs, persistent organic pollutants. It owns high contents of organic matters and water. High-efficiency and low-cost dehydration of sludge is the key of sludge disposal. How to improve sludge dehydration efficiency is the research hotspot in the world. In this study, effects of hydrogen peroxide content and pH on sludge dehydration were discussed by chemical disintegration technique. The optimal hydrogen peroxide content and pH were discussed, aiming to search a high-efficiency sludge conditioner.

  14. Chitosan as coagulant on cyanobacteria in lake restoration management may cause rapid cell lysis

    NARCIS (Netherlands)

    Nunes Teixeira Mucci, Maira; Noyma, Natalia Pessoa; Magalhães, de Leonardo; Miranda, Marcela; Oosterhout, van Frank; Guedes, Iamê Alves; Huszar, Vera L.M.; Marinho, Marcelo Manzi; Lürling, Miquel

    2017-01-01

    Combining coagulant and ballast to remove cyanobacteria from the water column is a promising restoration technique to mitigate cyanobacterial nuisance in surface waters. The organic, biodegradable polymer chitosan has been promoted as a coagulant and is viewed as non-toxic. In this study, we show

  15. Chitosan as coagulant on cyanobacteria in lake restoration management may cause rapid cell lysis

    NARCIS (Netherlands)

    Mucci, Maira; Noyma, Natalia Pessoa; de Magalhaes, Leonardo; Miranda, Marcela; van Oosterhout, Frank; Guedes, Iame Alves; Huszar, Vera L. M.; Marinho, Marcelo Manzi; Lürling, Miquel

    2017-01-01

    Combining coagulant and ballast to remove cyanobacteria from the water column is a promising restoration technique to mitigate cyanobacterial nuisance in surface waters. The organic, biodegradable polymer chitosan has been promoted as a coagulant and is viewed as non-toxic. In this study, we show

  16. Plasma clot lysis time and its association with cardiovascular risk factors in black Africans.

    Directory of Open Access Journals (Sweden)

    Zelda de Lange

    Full Text Available Studies in populations of European descent show longer plasma clot lysis times (CLT in patients with cardiovascular disease (CVD than in controls. No data are available on the association between CVD risk factors and fibrinolytic potential in black Africans, a group undergoing rapid urbanisation with increased CVD prevalence. We investigated associations between known CVD risk factors and CLT in black Africans and whether CLTs differ between rural and urban participants in light of differences in CVD risk.Data from 1000 rural and 1000 urban apparently healthy black South Africans (35-60 years were cross-sectionally analysed.Increased PAI-1(act, BMI, HbA1c, triglycerides, the metabolic syndrome, fibrinogen concentration, CRP, female sex and positive HIV status were associated with increased CLTs, while habitual alcohol consumption associated with decreased CLT. No differences in CLT were found between age and smoking categories, contraceptive use or hyper- and normotensive participants. Urban women had longer CLT than rural women while no differences were observed for men.CLT was associated with many known CVD risk factors in black Africans. Differences were however observed, compared to data from populations of European descent available in the literature, suggesting possible ethnic differences. The effect of urbanisation on CLT is influenced by traditional CVD risk factors and their prevalence in urban and rural communities.

  17. Floor of the nose mucosa lysis and labial abscess caused by a bee sting.

    Science.gov (United States)

    Alemán Navas, Ramón Manuel; Martínez Mendoza, María Guadalupe; Herrera, Henry; Herrera, Helen Piccolo de

    2009-01-01

    Hymenoptera order includes bees, which have a stinging apparatus at the tail capable of delivering venom to the affected tissues. Myocardial infarction, acute renal failure, Necrotizing fasciitis, fatal infection and hemifacial asymmetry, are some of the unusual reactions reported following hymenoptera stings. This paper reports a case of bee sting in the right floor of the nose that mimicked an odontogenic infection affecting the upper lip, canine space and nasal cavity such as in cases of infection secondary to pulpal or periodontal pathology of the anterior teeth. After a thorough clinical and radiographic examination, odontogenic infection was discarded and the diagnosis of floor of the nose mucosal lysis and lip abscess secondary to a bee sting was made. This case was successfully managed with adequate incision, drainage and antibiotics without any further complication. There are several reports of unusual reactions following hymenoptera stings. However, just a few of them referred to infections of local reactions and none of them related to the anatomic location affected in the patient of the present case. Early diagnosis and treatment prevented infection dissemination and the likelihood of tissue necrosis as in previously reported cases of Necrotizing fasciitis.

  18. Large-scale clinical comparison of the lysis-centrifugation and radiometric systems for blood culture

    International Nuclear Information System (INIS)

    Brannon, P.; Kiehn, T.E.

    1985-01-01

    The Isolator 10 lysis-centrifugation blood culture system (E. I. du Pont de Nemours and Co., Inc., Wilmington, Del.) was compared with the BACTEC radiometric method (Johnston Laboratories, Inc., Towson, Md.) with 6B and 7D broth media for the recovery of bacteria and yeasts. From 11,000 blood cultures, 1,174 clinically significant organisms were isolated. The Isolator system recovered significantly more total organisms, members of the family Enterobacteriaceae, Staphylococcus spp., and yeasts. The BACTEC system recovered significantly more Pseudomonas spp., Streptococcus spp., and anaerobes. Of the Isolator colony counts, 87% measured less than 11 CFU/ml of blood. Organisms, on an average, were detected the same day from each of the two culture systems. Only 13 of the 975 BACTEC isolates (0.01%) were recovered by subculture of growth-index-negative bottles, and 12 of the 13 were detected in another broth blood culture taken within 24 h. Contaminants were recovered from 4.8% of the Isolator 10 and 2.3% of the BACTEC cultures

  19. Plasma clot lysis time and its association with cardiovascular risk factors in black Africans.

    Science.gov (United States)

    de Lange, Zelda; Pieters, Marlien; Jerling, Johann C; Kruger, Annamarie; Rijken, Dingeman C

    2012-01-01

    Studies in populations of European descent show longer plasma clot lysis times (CLT) in patients with cardiovascular disease (CVD) than in controls. No data are available on the association between CVD risk factors and fibrinolytic potential in black Africans, a group undergoing rapid urbanisation with increased CVD prevalence. We investigated associations between known CVD risk factors and CLT in black Africans and whether CLTs differ between rural and urban participants in light of differences in CVD risk.Data from 1000 rural and 1000 urban apparently healthy black South Africans (35-60 years) were cross-sectionally analysed.Increased PAI-1(act), BMI, HbA1c, triglycerides, the metabolic syndrome, fibrinogen concentration, CRP, female sex and positive HIV status were associated with increased CLTs, while habitual alcohol consumption associated with decreased CLT. No differences in CLT were found between age and smoking categories, contraceptive use or hyper- and normotensive participants. Urban women had longer CLT than rural women while no differences were observed for men.CLT was associated with many known CVD risk factors in black Africans. Differences were however observed, compared to data from populations of European descent available in the literature, suggesting possible ethnic differences. The effect of urbanisation on CLT is influenced by traditional CVD risk factors and their prevalence in urban and rural communities.

  20. A super-family of transcriptional activators regulates bacteriophage packaging and lysis in Gram-positive bacteria

    Science.gov (United States)

    Quiles-Puchalt, Nuria; Tormo-Más, María Ángeles; Campoy, Susana; Toledo-Arana, Alejandro; Monedero, Vicente; Lasa, Íñigo; Novick, Richard P.; Christie, Gail E.; Penadés, José R.

    2013-01-01

    The propagation of bacteriophages and other mobile genetic elements requires exploitation of the phage mechanisms involved in virion assembly and DNA packaging. Here, we identified and characterized four different families of phage-encoded proteins that function as activators required for transcription of the late operons (morphogenetic and lysis genes) in a large group of phages infecting Gram-positive bacteria. These regulators constitute a super-family of proteins, here named late transcriptional regulators (Ltr), which share common structural, biochemical and functional characteristics and are unique to this group of phages. They are all small basic proteins, encoded by genes present at the end of the early gene cluster in their respective phage genomes and expressed under cI repressor control. To control expression of the late operon, the Ltr proteins bind to a DNA repeat region situated upstream of the terS gene, activating its transcription. This involves the C-terminal part of the Ltr proteins, which control specificity for the DNA repeat region. Finally, we show that the Ltr proteins are the only phage-encoded proteins required for the activation of the packaging and lysis modules. In summary, we provide evidence that phage packaging and lysis is a conserved mechanism in Siphoviridae infecting a wide variety of Gram-positive bacteria. PMID:23771138

  1. Determining Human Clot Lysis Time (in vitro with Plasminogen/Plasmin from Four Species (Human, Bovine, Goat, and Swine

    Directory of Open Access Journals (Sweden)

    Omaira Cañas Bermúdez

    2015-05-01

    Full Text Available Cardiovascular disease is the leading cause of death worldwide, including failures in the plasminogen/plasmin system which is an important factor in poor lysis of blood clots. This article studies the fibrinolytic system in four species of mammals, and it identifies human plasminogen with highest thrombolysis efficiency. It examines plasminogen from four species (human, bovine, goat, and swine and identifies the most efficient one in human clot lysis in vitro. All plasminogens were identically purified by affinity chromatography. Human fibrinogen was purified by fractionation with ethanol. The purification of both plasminogen and fibrinogen was characterized by one-dimensional SDS-PAGE (10%. Human clot formation in vitro and its dissolution by plasminogen/plasmin consisted of determining lysis time from clot formation to its dilution. Purification of proteins showed greater than 95% purity, human plasminogen showed greater ability to lyse clot than animal plasminogen. The article concludes that human plasminogen/plasmin has the greatest catalysis and efficiency, as it dissolves human clot up to three times faster than that of irrational species.

  2. [Ultrasound dynamics lysis apex thrombus as an objective criterion of effectiveness of anticoagulation therapy in venous thrombosis].

    Science.gov (United States)

    Kalinin, R E; Suchkov, I A; Pshennikov, A S; Agapov, A B

    2016-01-01

    To assess the effectiveness of anticoagulant therapy (ACT) for the treatment of patients with deep venous thrombosis (DVT) of the lower extremities. The study considered ultrasonic characteristics of lysis of the proximal part of thrombus: localization and nature of venous thrombosis, the length and diameter of the proximal floating part of the thrombus, and duration of the venous thrombosis. Depending on the ACT options patients were divided into 3 groups: Group 1 (18 patients) received rivaroxaban, group 2 (19 patients) received enoxaparin sodium with subsequent transition to warfarin, and 3 group (19 patietns) received enoxaparin sodium, followed by administration of rivaroxaban. Treatment with rivaroxaban was preferable over standard ACT with enoxaparin/warfarin with regards to the lysis of thrombus when duration of thrombosis did not exceed 10 days. In 10.5% of patients who received warfarin flotation of thrombi remained for 14 days; the length of the floating part of the thrombi did not exceed 3 cm. Such circumstances and inability to reach a therapeutic INR value required cava filter placement. Treatment with enoxaparin sodium followed by the administration of rivaroxaban was found to be the most efficient ACT regimen as there was no negative dynamics of ultrasound characteristics of lysis of thrombi at any duration of the disease.

  3. Relative efficacy of the argon green, argon blue-green, and krypton red lasers for 10-0 nylon subconjunctival laser suture lysis.

    Science.gov (United States)

    Mudgil, A V; To, K W; Balachandran, R M; Janigian, R H; Tsiaras, W G

    1999-01-01

    To determine the optimal wavelength for subconjunctival laser suture lysis. 130 black monofilament 10-0 nylon sutures were sewn subconjunctivally into the bare sclera of enucleated rabbit globes. The lowest energy levels facilitating laser suture lysis were determined for the argon green (514.5 NM), argon blue-green (488.0 NM, 514.5 NM), and krypton red (647.1 NM) wavelengths. In addition, absorption spectroscopy was performed on the suture material and conjunctiva using the Perkin Elmer W/VIS Lambda 2 spectrometer. Krypton red produced the fewest buttonhole defects, and it was also the most efficient energy source for suture lysis (P = 0.0001) under nontenectomized conjunctiva. Absorbance spectra studies revealed peak absorbance at 628 NM for the 10-0 nylon suture material. Based on animal and absorption spectroscopy studies, krypton red may be a safer and more efficient wavelength for subconjunctival laser suture lysis.

  4. Comparison of the lysis centrifugation method with the conventional blood culture method in cases of sepsis in a tertiary care hospital.

    Science.gov (United States)

    Parikh, Harshal R; De, Anuradha S; Baveja, Sujata M

    2012-07-01

    Physicians and microbiologists have long recognized that the presence of living microorganisms in the blood of a patient carries with it considerable morbidity and mortality. Hence, blood cultures have become critically important and frequently performed test in clinical microbiology laboratories for diagnosis of sepsis. To compare the conventional blood culture method with the lysis centrifugation method in cases of sepsis. Two hundred nonduplicate blood cultures from cases of sepsis were analyzed using two blood culture methods concurrently for recovery of bacteria from patients diagnosed clinically with sepsis - the conventional blood culture method using trypticase soy broth and the lysis centrifugation method using saponin by centrifuging at 3000 g for 30 minutes. Overall bacteria recovered from 200 blood cultures were 17.5%. The conventional blood culture method had a higher yield of organisms, especially Gram positive cocci. The lysis centrifugation method was comparable with the former method with respect to Gram negative bacilli. The sensitivity of lysis centrifugation method in comparison to conventional blood culture method was 49.75% in this study, specificity was 98.21% and diagnostic accuracy was 89.5%. In almost every instance, the time required for detection of the growth was earlier by lysis centrifugation method, which was statistically significant. Contamination by lysis centrifugation was minimal, while that by conventional method was high. Time to growth by the lysis centrifugation method was highly significant (P value 0.000) as compared to time to growth by the conventional blood culture method. For the diagnosis of sepsis, combination of the lysis centrifugation method and the conventional blood culture method with trypticase soy broth or biphasic media is advocable, in order to achieve faster recovery and a better yield of microorganisms.

  5. Local lysis with Alteplase for the treatment of acute embolic leg ischemia following the use of the Duett trademark closure device: preliminary results

    International Nuclear Information System (INIS)

    Schuermann, K.; Buecker, A.; Wingen, M.; Tacke, J.; Wein, B.; Guenther, R.W.; Janssens, U.

    2004-01-01

    Purpose: To analyze retrospectively the result of the alteplase lysis therapy of embolic complications following the use of the Duett closure device. Methods and Materials: For 3.5 years, the Duett closure device was used in 1,398 angiographies to close the femoral puncture site. The Duett device consists of a balloon and a liquid procoagulant containing collagen and thrombin, which is injected into the puncture tract under endovascular balloon protection of the arterial puncture site. In 9 patients (0.64%), the procoagulant was incidentally injected into the femoral artery causing acute leg ischemia. Eight patients received local lysis therapy with alteplase via a contralateral femoral access. One patient underwent surgery. On average, 21 mg alteplase (4-35 mg) were administered within 14 h (4-21 h). The course of the lysis was followed angiographyically and clinically. All patients were inteerviewed by telephone 23 months (4-35 months) later.Results: In 3 patients, lysis was complete. In 5 patients, only little thrombotic material remained. In all patients, symptoms of ischemia resolved completely within the first hours after initiation of lysis. In 5 cases, bleeding occurred at the puncture site closed with the Duett device during lysis, including development of a false aneurysm in 2 cases. Complications led to premature termination (n=2) or interruption of the lysis (n=3). All complications were treated conservatively. Clinically, long-term sequelae were paresthesia and hypoesthesia in the lower leg and foot in 2 patients treated with lysis, and in the patient who underwent surgery. (orig.) [de

  6. Comparison of Yeast Cell Protein Solubilization Procedures for Two-dimensional Electrophoresis

    DEFF Research Database (Denmark)

    Harder, A; Wildgruber, R; Nawrocki, A

    1999-01-01

    Three different procedures for the solubilization of yeast (S. cerevisiae) cell proteins were compared on the basis of the obtained two-dimensional (2-D) polypeptide patterns. Major emphasis was laid on minimizing handling steps, protein modification or degradation, and quantitative loss of high...... with sodium dodecyl sulfate (SDS) buffer, consisting of 1% SDS and 100 mM tris(hydroxymethyl)aminomethane (Tris)-HCl, pH 7.0, followed by dilution with "standard" lysis buffer, and (iii) boiling the sample with SDS during cell lysis, followed by dilution with thiourea/urea lysis buffer (2 M thiourea/ 7 M urea...

  7. Constitutive Activation of NF-KB in Prostate Carcinoma Cells Through a Positive Feedback Loop: Implication of Inducible IKK-Related Kinase (IKKi)

    National Research Council Canada - National Science Library

    Budunova, Irina V

    2005-01-01

    .... During FYO2 we developed the conditions for RNA isolation from OCT-embedded frozen PC and BPH samples, developed conditions for cell lysis and IKKi immunoprecipitation from transfected cells using FLAG antibody...

  8. Large Gastric Perforation Sealed by Splenic Lysis: Emphasis on Indirect Signs – A Rare Case Report

    International Nuclear Information System (INIS)

    Garg, Lalit; Jain, Mansi; Taori, Kishor; Patil, Ajinky; Hatgaonkar, Anand; Rathod, Jawhar; Shah, Swenil; Patwa, Darshan; Kasat, Akshat

    2015-01-01

    Gastric perforation is a life-threatening condition, requiring early and reliable discovery. The delay before surgical treatment is a strong determinant of poor outcome, associated complications and hospitalization costs. By using ultrasound and multi-detector computed tomography (MDCT) we can further evaluate undiagnosed cases of silent gastric perforations presenting with non-specific acute abdomen. Here we bring forth the role of a radiologist in cases of perforation which present with indirect signs involving the organs forming the stomach bed, like the spleen, pancreas and kidney. A 25-year-old male patient presented with an acute onset of severe upper abdominal pain radiating to the back and vomiting. MDCT of the abdomen was done which revealed atrophic pancreas with organized collection in the sub-capsular location indenting the superior pole of the left kidney. Spleen was not visualized. The most striking imaging finding in that case was destruction of the splenic parenchyma with protrusion of the remaining tissue into the stomach lumen. The hypothesis behind this was a cascade of events which started with gastric perforation, spillage of highly destructive gastric juice over the stomach bed and finally becoming silent with rapid sealing of the defect by the omentum and the spleen. Acute abdomen is a diagnostic challenge to a clinician and radiologist with gastric perforation being a great mimicker of other urgent abdominal pathologies. To avoid a delayed diagnosis or a misdiagnosis, familiarity with typical and atypical imaging features is essential as in our case of splenic lysis. It acted as the 2 nd policeman and provided a great clue to solve the diagnostic dilemma

  9. Development of Augmented Leukemia/Lymphoma-Specific T-Cell Immunotherapy for Deployment with Haploidentical, Hematompoietic Progenitor-Cell Transplant

    Science.gov (United States)

    2011-05-01

    cells exhibited redirected specific lysis of a genetically modified EL4 target expressing 92% human CD19 (Figure 6a). T cells not genetically modified...but propagated by crosslinking CD3 using g-irradiated aAPC loaded with OKT3 did not appreciably lyse CD19 EL4 cells (Figure 6b). DISCUSSION We and...by genetically modified T cells. Lysis by chromium release assay of CD19+ EL4 tumor cells compared with CD19 parental EL4 cells by (a) T cells

  10. INDUCIBLE CELL LYSIS SYSTEM IN BACILLUS SUBTILIS AND TRANSFORMATION BY DNA RELEASED FROM LYSED CELLS. (R826107)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  11. An optimized protocol for isolating primary epithelial cell chromatin for ChIP.

    Directory of Open Access Journals (Sweden)

    James A Browne

    Full Text Available A critical part of generating robust chromatin immunoprecipitation (ChIP data is the optimization of chromatin purification and size selection. This is particularly important when ChIP is combined with next-generation sequencing (ChIP-seq to identify targets of DNA-binding proteins, genome-wide. Current protocols refined by the ENCODE consortium generally use a two-step cell lysis procedure that is applicable to a wide variety of cell types. However, the isolation and size selection of chromatin from primary human epithelial cells may often be particularly challenging. These cells tend to form sheets of formaldehyde cross-linked material in which cells are resistant to membrane lysis, nuclei are not released and subsequent sonication produces extensive high molecular weight contamination. Here we describe an optimized protocol to prepare high quality ChIP-grade chromatin from primary human bronchial epithelial cells. The ENCODE protocol was used as a starting point to which we added the following key steps to separate the sheets of formaldehyde-fixed cells prior to lysis. (1 Incubation of the formaldehyde-fixed adherent cells in Trypsin-EDTA (0.25% room temperature for no longer than 5 min. (2 Equilibration of the fixed cells in detergent-free lysis buffers prior to each lysis step. (3 The addition of 0.5% Triton X-100 to the complete cell membrane lysis buffer. (4 Passing the cell suspension (in complete cell membrane lysis buffer through a 25-gauge needle followed by continuous agitation on ice for 35 min. Each step of the modified protocol was documented by light microscopy using the Methyl Green-Pyronin dual dye, which stains cytoplasm red (Pyronin and the nuclei grey-blue (Methyl green. This modified method is reproducibly effective at producing high quality sheared chromatin for ChIP and is equally applicable to other epithelial cell types.

  12. A Simple Method for DNA Extraction from Mature Date Palm Leaves: Impact of Sand Grinding and Composition of Lysis Buffer

    Science.gov (United States)

    Arif, Ibrahim A.; Bakir, Mohammad A.; Khan, Haseeb A.; Ahamed, Anis; Al Farhan, Ahmad H.; Al Homaidan, Ali A.; Al Sadoon, Mohammad; Bahkali, Ali H.; Shobrak, Mohammad

    2010-01-01

    Molecular marker techniques have been widely used for cultivar identification of inbred date palms (Phoenix dactylifera L.; Arecaceae) and biodiversity conservation. Isolation of highly pure DNA is the prerequisite for PCR amplification and subsequent use such as DNA fingerprinting and sequencing of genes that have recently been developed for barcoding. To avoid problems related to the preservation and use of liquid nitrogen, we examined sterile sand for grinding the date palm leaves. Individual and combined effects of sodium chloride (NaCl), polyvinylpyrrolidone (PVP) and lithium chloride (LiCl) with the cetyltrimethylammonium bromide (CTAB) method for a DNA yield of sufficient purity and PCR amplification were evaluated in this study. Presence of LiCl and PVP alone or together in the lysis buffer did not significantly improve the DNA yield and purity compared with the addition of NaCl. Our study suggested that grinding of date palm leaf with sterile sand and inclusion of NaCl (1.4 M) in the lysis buffer without the costly use of liquid nitrogen, PVP and LiCl, provides a DNA yield of sufficient purity, suitable for PCR amplification. PMID:20957085

  13. [A comparative study of blood culture conventional method vs. a modified lysis/centrifugation technique for the diagnosis of fungemias].

    Science.gov (United States)

    Santiago, Axel Rodolfo; Hernández, Betsy; Rodríguez, Marina; Romero, Hilda

    2004-12-01

    The purpose of this work was to compare the efficacy of blood culture conventional method vs. a modified lysis/centrifugation technique. Out of 450 blood specimens received in one year, 100 where chosen for this comparative study: 60 from patients with AIDS, 15 from leukemic patients, ten from febrile neutropenic patients, five from patients with respiratory infections, five from diabetics and five from septicemic patients. The specimens were processed, simultaneously, according to the above mentioned methodologies with daily inspections searching for fungal growth in order to obtain the final identification of the causative agent. The number (40) of isolates recovered was the same using both methods, which included; 18 Candida albicans (45%), ten Candida spp. (25%), ten Histoplasma capsulatum (25%), and two Cryptococcus neoformans (5%). When the fungal growth time was compared by both methods, growth was more rapid when using the modified lysis/centrifugation technique than when using the conventional method. Statistical analysis revealed a significant difference (pcentrifugation technique showed to be more efficacious than the conventional one, and therefore the implementation of this methodology is highly recommended for the isolation of fungi from blood.

  14. Urate oxidase for the prevention and treatment of tumour lysis syndrome in children with cancer.

    Science.gov (United States)

    Cheuk, Daniel Kl; Chiang, Alan Ks; Chan, Godfrey Cf; Ha, Shau Yin

    2017-03-08

    Tumour lysis syndrome (TLS) is a serious complication of malignancies and can result in renal failure or death. Previous reviews did not find clear evidence of benefit of urate oxidase in children with cancer. This review is the second update of a previously published Cochrane review. To assess the effects and safety of urate oxidase for the prevention and treatment of TLS in children with malignancies. In March 2016 we searched CENTRAL, MEDLINE, Embase, and CINAHL. In addition, we searched the reference lists of all identified relevant papers, trials registers and other databases. We also screened conference proceedings and we contacted experts in the field and the manufacturer of rasburicase, Sanofi-aventis. Randomised controlled trials (RCT) and controlled clinical trials (CCT) of urate oxidase for the prevention or treatment of TLS in children under 18 years with any malignancy. Two review authors independently extracted trial data and assessed individual trial quality. We used risk ratios (RR) for dichotomous data and mean difference (MD) for continuous data. We included seven trials, involving 471 participants in the treatment groups and 603 participants in the control groups. No new studies were identified in the update. One RCT and five CCTs compared urate oxidase and allopurinol. Three trials tested Uricozyme, and three trials tested rasburicase for the prevention of TLS.The RCT did not evaluate the primary outcome (incidence of clinical TLS). It showed no clear evidence of a difference in mortality (both all-cause mortality (Fisher's exact test P = 0.23) and mortality due to TLS (no deaths in either group)), renal failure (Fisher's exact test P = 0.46), and adverse effects between the treatment and the control groups (Fisher's exact test P = 1.0). The frequency of normalisation of uric acid at four hours (10 out of 10 participants in the treatment group versus zero out of nine participants in the control group, Fisher's exact test P oxidase (RR 9.10, 95

  15. Evidence that pulsed electric field treatment enhances the cell wall porosity of yeast cells.

    Science.gov (United States)

    Ganeva, Valentina; Galutzov, Bojidar; Teissie, Justin

    2014-02-01

    The application of rectangular electric pulses, with 0.1-2 ms duration and field intensity of 2.5-4.5 kV/cm, to yeast suspension mediates liberation of cytoplasmic proteins without cell lysis. The aim of this study was to evaluate the effect of pulsed electric field with similar parameters on cell wall porosity of different yeast species. We found that electrically treated cells become more susceptible to lyticase digestion. In dependence on the strain and the electrical conditions, cell lysis was obtained at 2-8 times lower enzyme concentration in comparison with control untreated cells. The increase of the maximal lysis rate was between two and nine times. Furthermore, when applied at low concentration (1 U/ml), the lyticase enhanced the rate of protein liberation from electropermeabilized cells without provoking cell lysis. Significant differences in the cell surface of control and electrically treated cells were revealed by scanning electron microscopy. Data presented in this study allow us to conclude that electric field pulses provoke not only plasma membrane permeabilization, but also changes in the cell wall structure, leading to increased wall porosity.

  16. The homeostasis of Plasmodium falciparum-infected red blood cells.

    Directory of Open Access Journals (Sweden)

    Jakob M A Mauritz

    2009-04-01

    Full Text Available The asexual reproduction cycle of Plasmodium falciparum, the parasite responsible for severe malaria, occurs within red blood cells. A merozoite invades a red cell in the circulation, develops and multiplies, and after about 48 hours ruptures the host cell, releasing 15-32 merozoites ready to invade new red blood cells. During this cycle, the parasite increases the host cell permeability so much that when similar permeabilization was simulated on uninfected red cells, lysis occurred before approximately 48 h. So how could infected cells, with a growing parasite inside, prevent lysis before the parasite has completed its developmental cycle? A mathematical model of the homeostasis of infected red cells suggested that it is the wasteful consumption of host cell hemoglobin that prevents early lysis by the progressive reduction in the colloid-osmotic pressure within the host (the colloid-osmotic hypothesis. However, two critical model predictions, that infected cells would swell to near prelytic sphericity and that the hemoglobin concentration would become progressively reduced, remained controversial. In this paper, we are able for the first time to correlate model predictions with recent experimental data in the literature and explore the fine details of the homeostasis of infected red blood cells during five model-defined periods of parasite development. The conclusions suggest that infected red cells do reach proximity to lytic rupture regardless of their actual volume, thus requiring a progressive reduction in their hemoglobin concentration to prevent premature lysis.

  17. Tip chip : Subcellular sampling from single cancer cells

    NARCIS (Netherlands)

    Quist, Jos; Sarajlic, Edin; Lai, Stanley C.S.; Lemay, Serge G.

    2016-01-01

    To analyze the molecular content of single cells, cell lysis is typically required, yielding a snapshot of cell behavior only. To follow complex molecular profiles over time, subcellular sampling methods potentially can be used, but to date these methods involve laborious offline analysis. Here we

  18. RASCAL [Radiological Assessment System for Consequence AnaLysis]: A screening model for estimating doses from radiological accidents

    International Nuclear Information System (INIS)

    Sjoreen, A.L.; Athey, G.F.; Sakenas, C.A.; McKenna, T.J.

    1988-01-01

    The Radiological Assessment System for Consequence AnaLysis (RASCAL) is a new MS-DOS-based dose assessment model which has been written for the US Nuclear Regulatory Commission for use during response to radiological emergencies. RASCAL is designed to provide crude estimates of the effects of an accident while the accident is in progress and only limited information is available. It has been designed to be very simple to use and to run quickly. RASCAL is unique in that it estimates the source term based on fundamental plant conditions and does not rely solely on release rate estimation (e.g., Ci/sec of I-131). Therefore, it can estimate consequences of accidents involving unmonitored pathways or projected failures. RASCAL will replace the older model, IRDAM. 6 refs

  19. Detection of fungal DNA in lysis-centrifugation blood culture for the diagnosis of invasive candidiasis in neonatal patients.

    Science.gov (United States)

    Trovato, L; Betta, P; Romeo, M G; Oliveri, S

    2012-03-01

    We report data concerning the detection of fungal DNA directly from lysis-centrifugation blood culture to assess its value in the detection of fungaemia in 86 of the 347 patients admitted to the neonatal intensive-care unit between January 2009 and December 2010. The sensitivity and specificity of the PCR were 87.5% and 98.5%, respectively, with a positive predictive value of 93.3% and a negative predictive value of 97.1%. Detection of fungal DNA directly from blood culture Isolator 1.5 microbial tubes, without prior cultivation, is a promising approach for the rapid detection of Candida spp. in neonates with suspected candidaemia. © 2011 The Authors. Clinical Microbiology and Infection © 2011 European Society of Clinical Microbiology and Infectious Diseases.

  20. Effects of ultrasound, cysteamine, and x-rays on V79 Chinese hamster cells

    International Nuclear Information System (INIS)

    Fu, Y.K.

    1978-01-01

    Chinese hamster V79 cells were exposed to different intensities and durations of 1 MHz ultrasound and were studied for cell lysis and colony-forming ability. The threshold for cell lysis and loss of viability (reduction in colony-forming ability) were found to be ultrasonic intensity, sonication duration, and energy dependent. Above the threshold there was an initial correlation between ultrasound intensity and biological effect: the higher the intensity, the greater the amount of cell lysis and reduction in colony-forming ability. These effects were maximal at an intensity of 10-20 W/cm 2 , and were less at 30 W/cm 2 . Cells were also exposed to ultrasound in the presence of cysteamine and results are compared with the effects of x radiation on cells exposed in the presence of cysteamine or methionine

  1. Cell Lysis and Detoxification of Cyanotoxins Using a Novel Combination of Microbubble Generation and Plasma Microreactor Technology for Ozonation.

    Science.gov (United States)

    Pandhal, Jagroop; Siswanto, Anggun; Kuvshinov, Dmitriy; Zimmerman, William B; Lawton, Linda; Edwards, Christine

    2018-01-01

    There has been a steady rise in the incidences of algal blooms globally, and worryingly, there is increasing evidence that changes in the global climate are leading to a shift toward cyanobacterial blooms. Many cyanobacterial genera are harmful, producing several potent toxins, including microcystins, for which there are over 90 described analogues. There are a wide range of negative effects associated with these toxins including gastroenteritis, cytotoxicity, hepatotoxicity and neurotoxicity. Although a variety of oxidation based treatment methods have been described, ozonation and advanced oxidation are acknowledged as most effective as they readily oxidise microcystins to non-toxic degradation products. However, most ozonation technologies have challenges for scale up including high costs and sub-optimum efficiencies, hence, a low cost and scalable ozonation technology is needed. Here we designed a low temperature plasma dielectric barrier discharge (DBD) reactor with an incorporated fluidic oscillator for microbubble delivery of ozone. Both technologies have the potential to drastically reduce the costs of ozonation at scale. Mass spectrometry analysis revealed very rapid (cyanotoxins.

  2. Derivation of chicken induced pluripotent stem cells tolerant to Newcastle disease virus-induced lysis through multiple rounds of infection

    Science.gov (United States)

    Background: Newcastle disease (ND), caused by Newcastle disease virus (NDV), is a devastating disease of poultry and wild birds. ND is prevented by rigorous biocontainment and vaccination. One potential approach to prevent spread of the virus is production of birds that show innate resistance to NDV...

  3. High-intensity focused ultrasound sonothrombolysis: the use of perfluorocarbon droplets to achieve clot lysis at reduced acoustic power.

    Science.gov (United States)

    Pajek, Daniel; Burgess, Alison; Huang, Yuexi; Hynynen, Kullervo

    2014-09-01

    The purpose of this study was to evaluate use of intravascular perfluorocarbon droplets to reduce the sonication power required to achieve clot lysis with high-intensity focused ultrasound. High-intensity focused ultrasound with droplets was initially applied to blood clots in an in vitro flow apparatus, and inertial cavitation thresholds were determined. An embolic model for ischemic stroke was used to illustrate the feasibility of this technique in vivo. Recanalization with intravascular droplets was achieved in vivo at 24 ± 5% of the sonication power without droplets. Recanalization occurred in 71% of rabbits that received 1-ms pulsed sonications during continuous intravascular droplet infusion (p = 0.041 vs controls). Preliminary experiments indicated that damage was confined to the ultrasonic focus, suggesting that tolerable treatments would be possible with a more tightly focused hemispheric array that allows the whole focus to be placed inside of the main arteries in the human brain. Copyright © 2014 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  4. Thrombin activatable fibrinolysis inhibitor and clot lysis time in pregnant patients with antiphospholipid syndrome: relationship with pregnancy outcome and thrombosis.

    Science.gov (United States)

    Martinez-Zamora, Maria Angeles; Tassies, Dolors; Carmona, Francisco; Espinosa, Gerard; Cervera, Ricard; Reverter, Juan Carlos; Balasch, Juan

    2009-12-01

    Antiphospholipid syndrome (APS) pregnancies are associated with thrombotic obstetric complications, despite treatment. This study evaluated Thrombin Activatable Fibrinolysis Inhibitor (TAFI) levels, TAFI gene polymorphisms and Clot Lysis Time (CLT) in pregnant patients with APS in relation to pregnancy outcome and thrombosis. Group 1 consisted of 67 pregnant patients with APS. Group 2 included 66 pregnant patients with uneventful term pregnancies and delivery. Patients were sampled during each trimester and at baseline. TAFI antigen and CLT and two polymorphisms of the TAFI gene, Ala147Thr and +1542C/G, were determined. Significantly prolonged CLT was found at baseline in Group 1. Allele distribution of the TAFI gene polymorphisms was similar in both groups. Basal TAFI and CLT in patients with APS having an adverse or a good obstetrical outcome were similar. Comparison of TAFI and CLT baseline levels in patients with APS with or without previous thrombosis showed no statistical differences. Patients with APS have impairment in fibrinolysis evidenced by prolonged CLT at baseline. TAFI and CLT do not seem to be useful as markers of obstetric outcome or risk of thrombosis in patients with APS.

  5. Genome scan of clot lysis time and its association with thrombosis in a protein C deficient kindred

    Science.gov (United States)

    Meltzer, M.E.; Hasstedt, S.J.; Vossen, C.Y.; Callas, P.W.; de Groot, Ph.G.; Rosendaal, F.R.; Lisman, T.; Bovill, E.G.

    2011-01-01

    Summary Background Previously we found increased clot lysis time (CLT), as measured with a plasma-based assay, to increase the risk of venous thrombosis in two population-based case-control studies. Genes influencing CLT are yet unknown. Objectives and Patients/Methods We tested CLT as risk factor for venous thrombosis in Kindred Vermont II (n=346), a pedigree suffering from a high thrombosis risk, partially attributable to a type I protein C deficiency. Furthermore we tested for quantitative trait loci (QTL) for CLT using variance component linkage analysis. Results Protein C deficient family members had shorter CLT than non-deficient members (median CLT 67 versus 75 minutes). One standard deviation increase in CLT increased risk of venous thrombosis 2.4-fold in non-deficient family members. Protein C deficiency without elevated CLT increased risk 6.9-fold. Combining both risk factors yielded a 27.8-fold increased risk. Heritability of CLT was 42-52%. We found suggestive evidence of linkage on chromosome 11 (62 cM), partly explained by the prothrombin 20210A mutation, and on chromosome 13 (52 cM). Thrombin Activatable Fibrinolysis Inhibitor genotypes did not explain the variation in CLT. Conclusion Hypofibrinolysis appears to increase thrombosis risk in this family especially in combination with protein C deficiency. Protein C deficiency is associated with short CLT. CLT is partly genetically regulated. Suggestive QTL were found on chromosome 11 and 13. PMID:21575129

  6. Development and implementation of tPA clot lysis activity assay using ACL TOP™ hemeostasis testing system in QC laboratories

    Directory of Open Access Journals (Sweden)

    Lichun Huang

    2017-12-01

    Full Text Available This report describes the design, development, validation and long-term performance of tPA clot lysis activity assay using Advanced Chemistry Line Total Operational Performance (ACL TOP™ Homeostasis Testing System. The results of the study demonstrated robust and stable performance of the analytical method. The accuracy of the assay, expressed by percent recovery is 98–99%. The intermediate precision and repeatability precision, expressed as Relative Standard Deviation (RSD, was 3% and less than 2% respectively. The validated range is from 70% to 130% of the target potency of 5.8 × 105 IU/mg. The linearity of this range, expressed in correlation coefficient, is 0.997. After the assay is transferred to a QC laboratory, the assay retained high accuracy and precision with a success rate of >99%. Keywords: Potency assay, Clot lysis, Comparability, Automation

  7. DEPENDENCE BETWEEN ACYLATION DEGREE AND SPECIFIC LYSIS ACTITIVY OF THE PSEUDOMONAS AERUGINOSA М6 BACTERIOPHAGE

    Directory of Open Access Journals (Sweden)

    Martynov A. V.

    2016-06-01

    Full Text Available Introduction. The purpose of this work is to study the influence of various degrees of protein’s acylation on lytic activity and other biological properties of Pseudomonas M6 bacteriophage. Materials and methods. The subject of the study were samples of the Pseudomonas O 12 bacteriophage, hereinafter named the M6 phage. Pure phage lines were obtained from individual standard-morphology phage plaques (plaque-forming units, or PFUs after ten passes over the indicator strain. In subsequent experiments, M6 phage samples were selected that had a sufficient level of purity (homogeneous in the morphology of virions that inactivated the homologic antiphage serum by no less than 99.0% and the heterologic antibacterial serum by no more than 1%, and a titer no lower than 10 PFU per ml (PFU/ml. Titration of the phages was conducted using the standard bilayer agar. The crude protein content in the phage suspensions was determined using the spectroscopic method (at 280 and 260 nm. Succinylation of the phage samples was conducted according to the method developed by T.J. Molenaar. The phage’s lytic activity spectrum was determined through spot tests on 224 strains of the Pseudomonas genus and 106 strains of other genera (correspondingly, of strains Enterobacter -40, Escherichia -10, Citrobacter -8, Hafnia -7, Serratia -6, Shigella -10, Salmonella -8, Proteus -7 through the use of a phage suspension containing 10 5 - 10 6 PFU/ml. (This concentration of infectious phage corpuscles corresponds with the critical distribution of the M6 phage. The results of the research were subjected to statistical processing using single-factor dispersion analysis. Results and discussion. One hundred percent phage protein acylation leads to a loss of adsorption ability on sensitive cells and is accompanied by a significant (more than 103 times decrease in the level of specific lytic activity in the phage preparations. The succinylation type being studied does not cause

  8. Comparison of the Lysis Centrifugation Method with the Conventional Blood Culture Method in Cases of Sepsis in a Tertiary Care Hospital

    OpenAIRE

    Parikh, Harshal R; De, Anuradha S; Baveja, Sujata M

    2012-01-01

    Introduction : Physicians and microbiologists have long recognized that the presence of living microorganisms in the blood of a patient carries with it considerable morbidity and mortality. Hence, blood cultures have become critically important and frequently performed test in clinical microbiology laboratories for diagnosis of sepsis. Objectives: To compare the conventional blood culture method with the lysis centrifugation method in cases of sepsis. Materials and Methods: Two hundred ...

  9. Reduction of excess sludge in a sequencing batch reactor by lysis-cryptic growth using quick lime for disintegration under low temperature.

    Science.gov (United States)

    Lv, Xiao-Mei; Song, Ju-Sheng; Li, Ji; Zhai, Kun

    2017-08-01

    In the present study, quick-lime-based thermal-alkaline sludge disintegration (SD) under low temperature was combined with cryptic growth to investigate the excess sludge reduction efficiency in the sequencing batch reactor (SBR). The optimized condition of SD was as follows: T = 80℃, pH = 11, t = 180 min, and the SD rate was about 42.1%. With 65.6% of excess sludge disintegrated and returned to the SBR, the system achieved sludge reduction rate of about 40.1%. The lysis-cryptic growth still obtained satisfactory sludge reduction efficiency despite the comparative low SD rate, which suggested that disintegration rate might not be the decisive factor for cryptic-growth-based sludge reduction. Lysis-cryptic growth did not impact the effluent quality, yet the phosphorus removal performance was enhanced, with effluent total phosphorus concentration decreased by 0.3 mg/L (33%). Crystal compounds of calcium phosphate precipitate were detected in the system by Fourier transform infrared spectroscopy and X-ray diffraction, which indicated the phosphorus removal potential of SD using lime. Moreover, endogenous dehydrogenase activity of activated sludge in the lysis-cryptic system was enhanced, which was beneficial for sludge reduction. SD and cryptic growth in the present study demonstrates an economical and effective approach for sludge reduction.

  10. Clot lysis time in platelet-rich plasma: method assessment, comparison with assays in platelet-free and platelet-poor plasmas, and response to tranexamic acid.

    Science.gov (United States)

    Panes, Olga; Padilla, Oslando; Matus, Valeria; Sáez, Claudia G; Berkovits, Alejandro; Pereira, Jaime; Mezzano, Diego

    2012-01-01

    Fibrinolysis dysfunctions cause bleeding or predisposition to thrombosis. Platelets contain several factors of the fibrinolytic system, which could up or down regulate this process. However, the temporal relationship and relative contributions of plasma and platelet components in clot lysis are mostly unknown. We developed a clot lysis time (CLT) assay in platelet-rich plasma (PRP-CLT, with and without stimulation) and compared it to a similar one in platelet-free plasma (PFP) and to another previously reported test in platelet-poor plasma (PPP). We also studied the differential effects of a single dose of tranexamic acid (TXA) on these tests in healthy subjects. PFP- and PPP-CLT were significantly shorter than PRP-CLT, and the three assays were highly correlated (p plasma PAI-1, von Willebrand factor, fibrinogen, LDL-cholesterol, and triglycerides (p platelet aggregation/secretion, platelet counts, and pro-coagulant tests to explore factor X activation by platelets, PRP clotting time, and thrombin generation in PRP. Among all the studied variables, PFP-CLT was independently associated with plasma PAI-1, LDL-cholesterol, and triglycerides and, additionally, stimulated PRP-CLT was also independently associated with plasma fibrinogen. A single 1 g dose of TXA strikingly prolonged all three CLTs, but in contrast to the results without the drug, the lysis times were substantially shorter in non-stimulated or stimulated PRP than in PFP and PPP. This standardized PRP-CLT may become a useful tool to study the role of platelets in clot resistance and lysis. Our results suggest that initially, the platelets enmeshed in the clot slow down the fibrinolysis process. However, the increased clot resistance to lysis induced by TXA is overcome earlier in platelet-rich clots than in PFP or PPP clots. This is likely explained by the display of platelet pro-fibrinolytic effects. Focused research is needed to disclose the mechanisms for the relationship between CLT and plasma

  11. Hyperuricemia and tumor lysis syndrome in children with non-Hodgkin’s lymphoma and acute lymphoblastic leukemia

    Directory of Open Access Journals (Sweden)

    Betül Sevinir

    2011-03-01

    Full Text Available Objective: This study aimed to examine the incidence, clinical characteristics, and outcome of hyperuricemia and tumor lysis syndrome (TLS in children with non-Hodgkin’s lymphoma (NHL and acute lymphoblastic leukemia (ALL.Materials and Methods: This retrospective study included data from 327 patients (113 NHL and 214 ALL.Results: Hyperuricemia occurred in 26.5% and 12.6% of the patients with NHL and ALL, respectively. The corresponding figures for TLS were 15.9% and 0.47% (p=0.001. All hyperuricemic NHL patients had advanced disease and renal involvement was present in 53%. All hyperuricemic ALL patients had a leukocyte count >50,000 mm3 at the time of diagnosis. Among the hyperuricemic NHL and ALL patients, 96.6% and 66.6% had LDH ≥500 UI/L, respectively. Treatment consisted of hydration and allopurinol; none of the patients received urate oxidase. Among the patients that developed TLS, 26.3% had laboratory TLS, 42.1% had grade I or II TLS, and 31.6% had grade III or IV TLS. Uric acid levels returned to normal after a mean period of 3.5±2.5 and 3.05±0.8 d in NHL and ALL groups, respectively. In all, 7% of the patients with hyperuricemia required hemodialysis. None of the patients died.Conclusion: In this series the factors associated with a high-risk for TLS were renal involvement in NHL and high leucocyte count in ALL. Management with allopurinol and hydration was effective in this group of patients with high tumor burden.

  12. Genome scan of clot lysis time and its association with thrombosis in a protein C-deficient kindred.

    Science.gov (United States)

    Meltzer, M E; Hasstedt, S J; Vossen, C Y; Callas, P W; DE Groot, Ph G; Rosendaal, F R; Lisman, T; Bovill, E G

    2011-07-01

     Previously, we found increased clot-lysis time (CLT), as measured with a plasma-based assay, to increase the risk of venous thrombosis in two population-based case-control studies. The genes influencing CLT are as yet unknown.  We tested CLT as risk factor for venous thrombosis in Kindred Vermont II (n = 346), a pedigree suffering from a high thrombosis risk, partially attributable to a type I protein C deficiency. Furthermore, we tested for quantitative trait loci (QTLs) for CLT, using variance component linkage analysis.  Protein C-deficient family members had shorter CLTs than non-deficient members (median CLT 67 min vs. 75 min). One standard deviation increase in CLT increased the risk of venous thrombosis 2.4-fold in non-deficient family members. Protein C deficiency without elevated CLT increased the risk 6.9-fold. Combining both risk factors yielded a 27.8-fold increased risk. The heritability of CLT was 42-52%. We found suggestive evidence of linkage on chromosome 11 (62 cM), partly explained by the prothrombin 20210A mutation, and on chromosome 13 (52 cM). Thrombin-activatable fibrinolysis inhibitor genotypes did not explain the variation in CLT. Hypofibrinolysis appears to increase thrombosis risk in this family, especially in combination with protein C deficiency. Protein C deficiency is associated with short CLT. CLT is partly genetically regulated. Suggestive QTLs were found on chromosomes 11 and 13. © 2011 International Society on Thrombosis and Haemostasis.

  13. Host lysozyme-mediated lysis of Lactococcus lactis facilitates delivery of colitis-attenuating superoxide dismutase to inflamed colons

    Science.gov (United States)

    Ballal, Sonia A.; Veiga, Patrick; Fenn, Kathrin; Michaud, Monia; Kim, Jason H.; Gallini, Carey Ann; Glickman, Jonathan N.; Quéré, Gaëlle; Garault, Peggy; Béal, Chloé; Derrien, Muriel; Courtin, Pascal; Kulakauskas, Saulius; Chapot-Chartier, Marie-Pierre; van Hylckama Vlieg, Johan; Garrett, Wendy S.

    2015-01-01

    Beneficial microbes that target molecules and pathways, such as oxidative stress, which can negatively affect both host and microbiota, may hold promise as an inflammatory bowel disease therapy. Prior work showed that a five-strain fermented milk product (FMP) improved colitis in T-bet−/− Rag2−/− mice. By varying the number of strains used in the FMP, we found that Lactococcus lactis I-1631 was sufficient to ameliorate colitis. Using comparative genomic analyses, we identified genes unique to L. lactis I-1631 involved in oxygen respiration. Respiration of oxygen results in reactive oxygen species (ROS) generation. Also, ROS are produced at high levels during intestinal inflammation and cause tissue damage. L. lactis I-1631 possesses genes encoding enzymes that detoxify ROS, such as superoxide dismutase (SodA). Thus, we hypothesized that lactococcal SodA played a role in attenuating colitis. Inactivation of the sodA gene abolished L. lactis I-1631’s beneficial effect in the T-bet−/− Rag2−/− model. Similar effects were obtained in two additional colonic inflammation models, Il10−/− mice and dextran sulfate sodium-treated mice. Efforts to understand how a lipophobic superoxide anion (O2−) can be detoxified by cytoplasmic lactoccocal SodA led to the finding that host antimicrobial-mediated lysis is a prerequisite for SodA release and SodA’s extracytoplasmic O2− scavenging. L. lactis I-1631 may represent a promising vehicle to deliver antioxidant, colitis-attenuating SodA to the inflamed intestinal mucosa, and host antimicrobials may play a critical role in mediating SodA’s bioaccessibility. PMID:26056274

  14. Current Developments in Prokaryotic Single Cell Whole Genome Amplification

    Energy Technology Data Exchange (ETDEWEB)

    Goudeau, Danielle; Nath, Nandita; Ciobanu, Doina; Cheng, Jan-Fang; Malmstrom, Rex

    2014-03-14

    Our approach to prokaryotic single-cell Whole Genome Amplification at the JGI continues to evolve. To increase both the quality and number of single-cell genomes produced, we explore all aspects of the process from cell sorting to sequencing. For example, we now utilize specialized reagents, acoustic liquid handling, and reduced reaction volumes eliminate non-target DNA contamination in WGA reactions. More specifically, we use a cleaner commercial WGA kit from Qiagen that employs a UV decontamination procedure initially developed at the JGI, and we use the Labcyte Echo for tip-less liquid transfer to set up 2uL reactions. Acoustic liquid handling also dramatically reduces reagent costs. In addition, we are exploring new cell lysis methods including treatment with Proteinase K, lysozyme, and other detergents, in order to complement standard alkaline lysis and allow for more efficient disruption of a wider range of cells. Incomplete lysis represents a major hurdle for WGA on some environmental samples, especially rhizosphere, peatland, and other soils. Finding effective lysis strategies that are also compatible with WGA is challenging, and we are currently assessing the impact of various strategies on genome recovery.

  15. UV-C irradiation of HSV-1 infected fibroblasts (HSV-FS) enhances human natural killer (NK) cell activity against these targets

    International Nuclear Information System (INIS)

    Pettera, L.; Fitzgerald-Bocarsly, P.

    1991-01-01

    Expression of Herpes Simplex Virus Type 1 (HSV-1) immediate early gene products has been bound to be sufficient for NK cell mediated lysis of HSV-1 infected FS. To block the targets at various stages in the infectious cycle, HSV-FS were irradiated with UV light for 1 min at 2, 6, and 20 hr post-infection. NK mediated lysis of 2 hr and 5 hr UV treated HSV-FS was 2-fold higher than non-UV treated HSV-FS despite a >99% inhibition in virus yield. In contrast, 20 hr infected targets were lysed less well than 2 and 6 hr targets despite strong glycoprotein expression and induction of high levels of interferon-alpha (IFN-α) production by effector PBMC's; this lysis was not enhanced by UV treatment. Since NK lysis of HSV-FS has been found to be dependent on an HLA-DR + accessory cell (AC), lysis of irradiated HSV-FS by PBMC's depleted of AC was measured. Such depletion eradicated NK lysis of the UV treated HSV-FS indicating that irradiation does not overcome the AC requirement for NK lysis. UV irradiation of another HLA-DR + dependent target, Vesicular Stomatitis Virus (VSV) infected FS led to a dramatic reduction in both NK lysis and IFN-α induction. HSV-1 is a DNA virus whose genes are expressed in a cascade fashion whereas VSV is an RNA virus. The authors hypothesize that the enhancement in AC dependent NK activity observed for UV irradiated HSV-FS, but not VSV-FS, targets is due to overproduction of either a cellular or viral gene product which specifically occurs early in the HSV-1 infectious cycle and is downregulated by 20 hr post-infection

  16. What Variables Are Associated With the Outcome of Arthroscopic Lysis and Lavage Surgery for Internal Derangement of the Temporomandibular Joint?

    Science.gov (United States)

    Haeffs, Tyler H; D'Amato, Lindsay N; Khawaja, Shehryar N; Keith, David A; Scrivani, Steven J

    2018-04-26

    Arthroscopic lysis and lavage surgery (AS) is an effective modality that can decrease pain and increase maximum interincisal opening (MIO) in patients with internal derangement (ID) of the temporomandibular joint (TMJ). However, some patients remain in pain or have limited mandibular range of motion despite AS. The purpose of this study was to determine the effectiveness, prevalence of adverse effects, and predictors of response to TMJ AS in patients with TMJ arthralgia and ID. A retrospective cohort study was conducted using data of patients who had undergone AS by a single surgeon (D.A.K.) from September 2010 to April 2015 in the Department of Oral and Maxillofacial Surgery at Massachusetts General Hospital (Boston, MA). Variables, including demographic data, medical history, and clinical presentation, were extracted and analyzed. Criteria for surgical success were defined as a postoperative MIO of at least 35 mm and a postoperative pain level no higher than 3 on an 11-point Likert-type numeric verbal pain rating scale. Appropriate descriptive and analytic statistics were computed and significance was set at a P value less than .05. Of the 247 participants, 226 (91.5%) were women. The mean age of the sample was 38 ± 15.4 years. Successful surgical outcome was achieved in 62.3% of patients. Based on logistic regression analysis, higher initial mean pain score and concurrent use of benzodiazepines were the only variables that predicted an unsuccessful surgical outcome (P < .001; P = .005). Adverse effects were reported by 13.4% of patients, the most common being postoperative increase in pain (13.4%), temporary malocclusion (1.2%), and temporary paresthesia in the preauricular region (0.4%). The results from this study indicate that in patients with ID of the TMJ unresponsive to noninvasive treatments, high initial pain scores and concurrent use of benzodiazepines are correlated with an unsuccessful outcome after AS. Copyright © 2018. Published by

  17. Assessment of Red Blood Cell Parameters and Peripheral Smear at ...

    African Journals Online (AJOL)

    Cold agglutination disease (CAD) is characterized by an auto‑antibody which is able to agglutinate red blood cells (RBCs) at temperatures lower than that of the body, and subsequently to activate the complement system responsible for lysis of RBCs. Patients show hemolytic anemia of varying degrees of severity, which ...

  18. Effects of AC magnetic field and carboxymethyldextran-coated magnetite nanoparticles on mice peritoneal cells

    International Nuclear Information System (INIS)

    Araujo Guedes, Maria Helena; Sadeghiani, Neda; Lima Guedes Peixoto, Danielle; Poubel Coelho, Julia; Santos Barbosa, Luzirlane; Bentes Azevedo, Ricardo; Kueckelhaus, Selma; Silva, Maria de Fatima da; Morais, Paulo Cesar; Guerrero Marques Lacava, Zulmira

    2005-01-01

    A portable apparatus was developed to perform magnetohyperthermia (MHT) assays. In order to investigate its efficiency on cell lysis, biological effects of the AC magnetic field exposure after carboxymethyldextran-coated magnetite-nanoparticles (CMDC) treatment were investigated. Phagocyte capacity, cell viability, and morphology data evidenced that the CMDC sample and the apparatus are useful to further investigate MHT in cancer therapy

  19. Application of mitomycin C after endoscopic lysis of congenital laryngeal web combined with epiglottic hypoplasia in a middle-aged man.

    Science.gov (United States)

    Roh, Jong-Lyel

    2006-04-01

    Laryngeal webs and epiglottic hypoplasias are uncommon congenital anomalies. Anterior glottic web combined with epiglottic hypoplasia was found in a middle-aged man presenting with hoarseness and dyspnea on exertion. This can be considered as a unique isolated defect of the larynx during early fetal development. The laryngeal web can be successfully treated in a single stage with endoscopic lysis and topical application of mitomycin C for prevention of anterior glottic restenosis. This case and prior reports suggest that the novel approach may be effective in the treatment of laryngeal webs.

  20. Changes in clot lysis levels of reteplase and streptokinase following continuous wave ultrasound exposure, at ultrasound intensities following attenuation from the skull bone

    Directory of Open Access Journals (Sweden)

    Roijer Anders

    2008-08-01

    Full Text Available Abstract Background Ultrasound (US has been used to enhance thrombolytic therapy in the treatment of stroke. Considerable attenuation of US intensity is however noted if US is applied over the temporal bone. The aim of this study was therefore to explore possible changes in the effect of thrombolytic drugs during low-intensity, high-frequency continuous-wave ultrasound (CW-US exposure. Methods Clots were made from fresh venous blood drawn from healthy volunteers. Each clot was made from 1.4 ml blood and left to coagulate for 1 hour in a plastic test-tube. The thrombolytic drugs used were, 3600 IU streptokinase (SK or 0.25 U reteplase (r-PA, which were mixed in 160 ml 0.9% NaCl solution. Continuous-wave US exposure was applied at a frequency of 1 MHz and intensities ranging from 0.0125 to 1.2 W/cm2. For each thrombolytic drug (n = 2, SK and r-PA and each intensity (n = 9 interventional clots (US-exposed, n = 6 were submerged in thrombolytic solution and exposed to CW-US while control clots (also submerged in thrombolytic solution, n = 6 were left unexposed to US. To evaluate the effect on clot lysis, the haemoglobin (Hb released from each clot was measured every 20 min for 1 hour (20, 40 and 60 min. The Hb content (mg released was estimated by spectrophotometry at 540 nm. The difference in effect on clot lysis was expressed as the difference in the amount of Hb released between pairs of US-exposed clots and control clots. Statistical analysis was performed using Wilcoxon's signed rank test. Results Continuous-wave ultrasound significantly decreased the effects of SK at intensities of 0.9 and 1.2 W/cm2 at all times (P 2 and at 1.2 W/cm2, following 40 min exposure at 0.3, 0.6, 0.9 and at 1.2 W/cm2, and following 60 min of exposure at 0.05 0.3, 0.6, 0.9 and at 1.2 W/cm2 (all P Conclusion Increasing intensities of CW-US exposure resulted in increased clot lysis of r-PA-treated blood clots, but decreased clot lysis of SK-treated clots.

  1. Transcatheter arterial embolization with trisacryl gelatin microspheres (Embosphere®) leads to life-threatening tumor lysis syndrome in a rectal carcinoid patient with hepatic metastases

    International Nuclear Information System (INIS)

    Lo, Yuan-Hao; Tsai, Ming-Tsun; Kuo, Chen-Yu; Liu, Wen-Sheng; Lee, Rheun-Chuan; Yeh, Yi-Chen; Li, Chung-Pin; Chen, Jinn-Yang; Chao, Yee

    2012-01-01

    The incidence of gastrointestinal carcinoids appears to be increasing, and the rectum is the third most common location. Transcatheter arterial embolization (TAE) with trisacryl gelatin microspheres (Embosphere ® ) has been reported as an effective method for hepatic metastases of rectal carcinoids. Complications are uncommon and usually of minor consequence. We report an unusual case of a 34-year-old man with tumor lysis syndrome following TAE with Embosphere ® in a patient with multiple hepatic metastases of a rectal carcinoid. Early detection and effective treatment are essential for this rare but potentially catastrophic complication

  2. The solubilisation of boar sperm membranes by different detergents - a microscopic, MALDI-TOF MS, 31P NMR and PAGE study on membrane lysis, extraction efficiency, lipid and protein composition

    Directory of Open Access Journals (Sweden)

    Müller Karin

    2009-11-01

    Full Text Available Abstract Background Detergents are often used to isolate proteins, lipids as well as "detergent-resistant membrane domains" (DRMs from cells. Different detergents affect different membrane structures according to their physico-chemical properties. However, the effects of different detergents on membrane lysis of boar spermatozoa and the lipid composition of DRMs prepared from the affected sperm membranes have not been investigated so far. Results Spermatozoa were treated with the selected detergents Pluronic F-127, sodium cholate, CHAPS, Tween 20, Triton X-100 and Brij 96V. Different patterns of membrane disintegration were observed by light and electron microscopy. In accordance with microscopic data, different amounts of lipids and proteins were released from the cells by the different detergents. The biochemical methods to assay the phosphorus and cholesterol contents as well as 31P NMR to determine the phospholipids were not influenced by the presence of detergents since comparable amounts of lipids were detected in the organic extracts from whole cell suspensions after exposure to each detergent. However, matrix-assisted laser desorption and ionization time-of-flight mass spectrometry applied to identify phospholipids was essentially disturbed by the presence of detergents which exerted particular suppression effects on signal intensities. After separation of the membrane fractions released by detergents on a sucrose gradient only Triton X-100 and sodium cholate produced sharp turbid DRM bands. Only membrane solubilisation by Triton X-100 leads to an enrichment of cholesterol, sphingomyelin, phosphatidylinositol and phosphatidylethanolamine in a visible DRM band accompanied by a selective accumulation of proteins. Conclusion The boar sperm membranes are solubilised to a different extent by the used detergents. Particularly, the very unique DRMs isolated after Triton X-100 exposure are interesting candidates for further studies regarding the

  3. Fibrin-specific and effective clot lysis requires both plasminogen activators and for them to be in a sequential rather than simultaneous combination.

    Science.gov (United States)

    Pannell, R; Li, S; Gurewich, V

    2017-08-01

    Thrombolysis with tissue plasminogen activator (tPA) has been a disappointment and has now been replaced by an endovascular procedure whenever possible. Nevertheless, thrombolysis remains the only means by which circulation in a thrombosed artery can be restored rapidly. In contrast to tPA monotherapy, endogenous fibrinolysis uses both tPA and urokinase plasminogen activator (uPA), whose native form is a proenzyme, prouPA. This combination is remarkably effective as evidenced by the fibrin degradation product, D-dimer, which is invariably present in plasma. The two activators have complementary mechanisms of plasminogen activation and are synergistic in combination. Since tPA initiates fibrinolysis when released from the vessel wall and prouPA is in the blood, they induce fibrinolysis sequentially. It was postulated that this may be more effective and fibrin-specific. The hypothesis was tested in a model of clot lysis in plasma in which a clot was first exposed to tPA for 5 min, washed and incubated with prouPA. Lysis was compared with that of clots incubated with both activators simultaneously. The sequential combination was almost twice as effective and caused less fibrinogenolysis than the simultaneous combination (p < 0.0001) despite having significantly less tPA, as a result of the wash. A mechanism is described by which this phenomenon can be explained. The findings are believed to have significant therapeutic implications.

  4. A Simple Method for DNA Extraction from Mature Date Palm Leaves: Impact of Sand Grinding and Composition of Lysis Buffer

    Directory of Open Access Journals (Sweden)

    Mohammad Al Sadoon

    2010-09-01

    Full Text Available Molecular marker techniques have been widely used for cultivar identification of inbred date palms (Phoenix dactylifera L.; Arecaceae and biodiversity conservation. Isolation of highly pure DNA is the prerequisite for PCR amplification and subsequent use such as DNA fingerprinting and sequencing of genes that have recently been developed for barcoding. To avoid problems related to the preservation and use of liquid nitrogen, we examined sterile sand for grinding the date palm leaves. Individual and combined effects of sodium chloride (NaCl, polyvinylpyrrolidone (PVP and lithium chloride (LiCl with the cetyltrimethylammonium bromide (CTAB method for a DNA yield of sufficient purity and PCR amplification were evaluated in this study. Presence of LiCl and PVP alone or together in the lysis buffer did not significantly improve the DNA yield and purity compared with the addition of NaCl. Our study suggested that grinding of date palm leaf with sterile sand and inclusion of NaCl (1.4 M in the lysis buffer without the costly use of liquid nitrogen, PVP and LiCl, provides a DNA yield of sufficient purity, suitable for PCR amplification.

  5. Characterization of a synthetic bacterial self-destruction device for programmed cell death and for recombinant proteins release

    Directory of Open Access Journals (Sweden)

    Lupotto Manuel

    2011-06-01

    Full Text Available Abstract Background Bacterial cell lysis is a widely studied mechanism that can be achieved through the intracellular expression of phage native lytic proteins. This mechanism can be exploited for programmed cell death and for gentle cell disruption to release recombinant proteins when in vivo secretion is not feasible. Several genetic parts for cell lysis have been developed and their quantitative characterization is an essential step to enable the engineering of synthetic lytic systems with predictable behavior. Results Here, a BioBrick™ lysis device present in the Registry of Standard Biological Parts has been quantitatively characterized. Its activity has been measured in E. coli by assembling the device under the control of a well characterized N-3-oxohexanoyl-L-homoserine lactone (HSL -inducible promoter and the transfer function, lysis dynamics, protein release capability and genotypic and phenotypic stability of the device have been evaluated. Finally, its modularity was tested by assembling the device to a different inducible promoter, which can be triggered by heat induction. Conclusions The studied device is suitable for recombinant protein release as 96% of the total amount of the intracellular proteins was successfully released into the medium. Furthermore, it has been shown that the device can be assembled to different input devices to trigger cell lysis in response to a user-defined signal. For this reason, this lysis device can be a useful tool for the rational design and construction of complex synthetic biological systems composed by biological parts with known and well characterized function. Conversely, the onset of mutants makes this device unsuitable for the programmed cell death of a bacterial population.

  6. Circulating gamma delta T cells are activated and depleted during progression of high-grade gliomas: Implications for gamma delta T cell therapy of GBM

    Science.gov (United States)

    Glioblastoma multiforme (GBM) remains frustratingly impervious to any existing therapy. We have previously shown that GBM is sensitive to recognition and lysis by ex vivo activated gamma delta T cells, a minor subset of lymphocytes that innately recognize autologous stress-associated target antigens...

  7. Lysis to Kill: Evaluation of the Lytic Abilities, and Genomics of Nine Bacteriophages Infective for Gordonia spp. and Their Potential Use in Activated Sludge Foam Biocontrol.

    Directory of Open Access Journals (Sweden)

    Zoe A Dyson

    Full Text Available Nine bacteriophages (phages infective for members of the genus Gordonia were isolated from wastewater and other natural water environments using standard enrichment techniques. The majority were broad host range phages targeting more than one Gordonia species. When their genomes were sequenced, they all emerged as double stranded DNA Siphoviridae phages, ranging from 17,562 to 103,424 bp in size, and containing between 27 and 127 genes, many of which were detailed for the first time. Many of these phage genomes diverged from the expected modular genome architecture of other characterized Siphoviridae phages and contained unusual lysis gene arrangements. Whole genome sequencing also revealed that infection with lytic phages does not appear to prevent spontaneous prophage induction in Gordonia malaquae lysogen strain BEN700. TEM sample preparation techniques were developed to view both attachment and replication stages of phage infection.

  8. Nanochannel Electroporation as a Platform for Living Cell Interrogation in Acute Myeloid Leukemia.

    Science.gov (United States)

    Zhao, Xi; Huang, Xiaomeng; Wang, Xinmei; Wu, Yun; Eisfeld, Ann-Kathrin; Schwind, Sebastian; Gallego-Perez, Daniel; Boukany, Pouyan E; Marcucci, Guido I; Lee, Ly James

    2015-12-01

    A living cell interrogation platform based on nanochannel electroporation is demonstrated with analysis of RNAs in single cells. This minimally invasive process is based on individual cells and allows both multi-target analysis and stimulus-response analysis by sequential deliveries. The unique platform possesses a great potential to the comprehensive and lysis-free nucleic acid analysis on rare or hard-to-transfect cells.

  9. In black South Africans from rural and urban communities, the 4G/5G PAI-1 polymorphism influences PAI-1 activity, but not plasma clot lysis time.

    Directory of Open Access Journals (Sweden)

    Zelda de Lange

    Full Text Available Data on genetic and environmental factors influencing PAI-1 levels and their consequent effect on clot lysis in black African populations are limited. We identified polymorphisms in the promoter area of the PAI-1 gene and determined their influence on PAI-1act levels and plasma clot lysis time (CLT. We also describe gene-environment interactions and the effect of urbanisation. Data from 2010 apparently healthy urban and rural black participants from the South African arm of the PURE study were cross-sectionally analysed. The 5G allele frequency of the 4G/5G polymorphism was 0.85. PAI-1act increased across genotypes in the urban subgroup (p = 0.009 but not significantly in the rural subgroup, while CLT did not differ across genotypes. Significant interaction terms were found between the 4G/5G polymorphism and BMI, waist circumference and triglycerides in determining PAI-1act, and between the 4G/5G polymorphism and fibrinogen and fibrinogen gamma prime in determining CLT. The C428T and G429A polymorphisms did not show direct relationships with PAI-1act or CLT but they did influence the association of other environmental factors with PAI-1act and CLT. Several of these interactions differed significantly between rural and urban subgroups, particularly in individuals harbouring the mutant alleles. In conclusion, although the 4G/5G polymorphism significantly affected PAI-1act, it contributed less than 1% to the PAI-1act variance. (Central obesity was the biggest contributor to PAI-1act variance (12.5%. Urbanisation significantly influenced the effect of the 4G/5G polymorphism on PAI-1act as well as gene-environment interactions for the C428T and G429A genotypes in determining PAI-1act and CLT.

  10. In black South Africans from rural and urban communities, the 4G/5G PAI-1 polymorphism influences PAI-1 activity, but not plasma clot lysis time.

    Science.gov (United States)

    de Lange, Zelda; Rijken, Dingeman C; Hoekstra, Tiny; Conradie, Karin R; Jerling, Johann C; Pieters, Marlien

    2013-01-01

    Data on genetic and environmental factors influencing PAI-1 levels and their consequent effect on clot lysis in black African populations are limited. We identified polymorphisms in the promoter area of the PAI-1 gene and determined their influence on PAI-1act levels and plasma clot lysis time (CLT). We also describe gene-environment interactions and the effect of urbanisation. Data from 2010 apparently healthy urban and rural black participants from the South African arm of the PURE study were cross-sectionally analysed. The 5G allele frequency of the 4G/5G polymorphism was 0.85. PAI-1act increased across genotypes in the urban subgroup (p = 0.009) but not significantly in the rural subgroup, while CLT did not differ across genotypes. Significant interaction terms were found between the 4G/5G polymorphism and BMI, waist circumference and triglycerides in determining PAI-1act, and between the 4G/5G polymorphism and fibrinogen and fibrinogen gamma prime in determining CLT. The C428T and G429A polymorphisms did not show direct relationships with PAI-1act or CLT but they did influence the association of other environmental factors with PAI-1act and CLT. Several of these interactions differed significantly between rural and urban subgroups, particularly in individuals harbouring the mutant alleles. In conclusion, although the 4G/5G polymorphism significantly affected PAI-1act, it contributed less than 1% to the PAI-1act variance. (Central) obesity was the biggest contributor to PAI-1act variance (12.5%). Urbanisation significantly influenced the effect of the 4G/5G polymorphism on PAI-1act as well as gene-environment interactions for the C428T and G429A genotypes in determining PAI-1act and CLT.

  11. Mechanisms of cytolysin-induced cell damage -- a role for auto- and paracrine signalling

    DEFF Research Database (Denmark)

    Skals, Marianne Gerberg; Prætorius, Helle

    2013-01-01

    Cytolysins inflict cell damage by forming pores in the plasma membrane. The Na(+) conductivity of these pores results in an ion influx that exceeds the capacity of the Na(+) /K(+) -pump to extrude Na(+) . This net load of intracellular osmolytes results in swelling and eventual lysis of the attac...

  12. Molecular Cloning and Nucleotide Sequence of the Gene Encoding the Major Peptidoglycan Hydrolase of Lactococcus lactis, a Muramidase Needed for Cell Separation

    NARCIS (Netherlands)

    Buist, Girbe; Kok, Jan; Leenhouts, Kees J.; Dabrowska, Magdalena; Venema, Gerhardus; Haandrikman, Alfred J.

    A gene of Lactococcus lactis subsp, cremoris MG1363 encoding a peptidoglycan hydrolase was identified in a genomic library of the strain in pUC19 by screening Escherichia coli transformants for cell wall lysis activity on a medium containing autoclaved, lyophilized Micrococcus lysodeikticus cells,

  13. Mycoplasma agalactiae Induces Cytopathic Effects in Infected Cells Cultured In Vitro.

    Directory of Open Access Journals (Sweden)

    Shrilakshmi Hegde

    Full Text Available Mycoplasma agalactiae is the etiological agent of the contagious agalactia syndrome in sheep and goats and causes significant economic losses worldwide. Yet the mechanism of pathogenesis is largely unknown. Even whole-genome sequence analysis of its pathogenic type strain did not lead to any conclusions regarding its virulence or pathogenicity factors. Although inflammation and tissue destruction at the local site of M. agalactiae infection are largely considered as effects of the host immune response, the direct effect of the agent on host cells is not completely understood. The aim of this study was to investigate the effect of M. agalactiae infection on the quality and viability of host cells in vitro. Changes in cell morphology including cell elongation, cytoplasm shrinkage and membrane blebbing were observed in infected HeLa cells. Chromatin condensation and increased caspase-3 cleavage in infected HeLa cells 48 h after infection suggests an apoptosis-like phenomenon in M. agalactiae-infected cells. In compliance with these results, decreased viability and cell lysis of M. agalactiae-infected HeLa cells was also observed. Measurement of the amount of LDH released after M. agalactiae infection revealed a time- and dose-dependent increase in HeLa cell lysis. A significant decrease in LDH released after gentamicin treatment of infected cells confirmed the major role of cytadherent M. agalactiae in inducing host cell lysis. This is the first study illustrating M. agalactiae's induction of cytopathic effects in infected HeLa cells. Further detailed investigation of infected host tissue for apoptotic markers might demonstrate the association between M. agalactiae-induced host cell lysis and the tissue destruction observed during M. agalactiae natural infection.

  14. Enhanced lysis by bispecific oncolytic measles viruses simultaneously using HER2/neu or EpCAM as target receptors

    Directory of Open Access Journals (Sweden)

    Jan RH Hanauer

    2016-01-01

    Full Text Available To target oncolytic measles viruses (MV to tumors, we exploit the binding specificity of designed ankyrin repeat proteins (DARPins. These DARPin-MVs have high tumor selectivity while maintaining excellent oncolytic potency. Stability, small size, and efficacy of DARPins allowed the generation of MVs simultaneously targeted to tumor marker HER2/neu and cancer stem cell (CSC marker EpCAM. For optimization, the linker connecting both DARPins was varied in flexibility and length. Flexibility had no impact on fusion helper activity whereas length had. MVs with bispecific MV-H are genetically stable and revealed the desired double-target specificity. In vitro, the cytolytic activity of bispecific MVs was superior or comparable to mono-targeted viruses depending on the target cells. In vivo, therapeutic efficacy of the bispecific viruses was validated in an orthotopic ovarian carcinoma model revealing an effective reduction of tumor mass. Finally, the power of bispecific targeting was demonstrated on cocultures of different tumor cells thereby mimicking tumor heterogeneity in vitro, more closely reflecting real tumors. Here, bispecific excelled monospecific viruses in efficacy. DARPin-based targeting domains thus allow the generation of efficacious oncolytic viruses with double specificity, with the potential to handle intratumoral variation of antigen expression and to simultaneously target CSCs and the bulk tumor mass.

  15. ADCC employing an NK cell line (haNK) expressing the high affinity CD16 allele with avelumab, an anti-PD-L1 antibody.

    Science.gov (United States)

    Jochems, Caroline; Hodge, James W; Fantini, Massimo; Tsang, Kwong Y; Vandeveer, Amanda J; Gulley, James L; Schlom, Jeffrey

    2017-08-01

    NK-92 cells, and their derivative, designated aNK, were obtained from a patient with non-Hodgkin lymphoma. Prior clinical studies employing adoptively transferred irradiated aNK cells have provided evidence of clinical benefit and an acceptable safety profile. aNK cells have now been engineered to express IL-2 and the high affinity (ha) CD16 allele (designated haNK). Avelumab is a human IgG1 anti-PD-L1 monoclonal antibody, which has shown evidence of clinical activity in a range of human tumors. Prior in vitro studies have shown that avelumab has the ability to mediate antibody-dependent cell-mediated cytotoxicity (ADCC) of human tumor cells when combined with NK cells. In the studies reported here, the ability of avelumab to enhance the lysis of a range of human carcinoma cells by irradiated haNK cells via the ADCC mechanism is demonstrated; this ADCC is shown to be inhibited by anti-CD16 blocking antibody and by concanamycin A, indicating the use of the granzyme/perforin pathway in tumor cell lysis. Studies also show that while NK cells have the ability to lyse aNK or haNK cells, the addition of NK cells to irradiated haNK cells does not inhibit haNK-mediated lysis of human tumor cells, with or without the addition of avelumab. Avelumab-mediated lysis of tumor cells by irradiated haNK cells is also shown to be similar to that of NK cells bearing the V/V Fc receptor high affinity allele. These studies thus provide the rationale for the clinical evaluation of the combined use of avelumab with that of irradiated adoptively transferred haNK cells. © 2017 UICC.

  16. 白血病合并肿瘤溶解综合征的诊治%Diagnosis and treatment of tumor lysis syndrome associated with leukemia

    Institute of Scientific and Technical Information of China (English)

    秘营昌

    2011-01-01

    肿瘤溶解综合征(TLS)是血液肿瘤科常见的急症,临床表现主要有高尿酸血症、高钾血症、高磷酸血症、低钙血症等,最终导致肾功能衰竭、心律失常、癫痫、神经系统并发症,甚至死亡.目前对TLS诊断、疾病危险度判断、治疗观点较一致,提高了TLS的诊断、治疗水平.%Tumor lysis syndrome (TLS) is a life-threatening oncological emergency characterized by metabolic abnormalities including hyperuricaernia,hyperphosphataemia,hyperkalaemia and hypocalcaemia. These metabolic complications will eventually lead to a series of complications. Now that the diagnosis of TI.S has been clarified, a panel of TLS experts have offered recommendations for evaluation of risks and prophylaxis of TLS to improve the prognosis of patients with TLS.

  17. The challenges of treating paraganglioma patients with 177Lu-DOTATATE PRRT: Catecholamine crises, tumor lysis syndrome and the need for modification of treatment protocols

    International Nuclear Information System (INIS)

    Makis, William; Mccann, Karey; Mcewan, Alexander J. B.

    2015-01-01

    A high percentage of paragangliomas express somatostatin receptors that can be utilized for targeted radioisotope therapy. The aim of this study was to describe and discuss the challenges of treating these tumors with 177 Lu-[DOTA0,Tyr3]octreotate (DOTATATE) radioisotope therapy using established protocols. Three paraganglioma patients were treated with 4–5 cycles of 177 Lu-DOTATATE and were evaluated for side effects and response to therapy. Two of the three patients developed severe adverse reactions following their first 177 Lu-DOTATATE treatment. One patient developed a catecholamine crisis and tumor lysis syndrome within hours of treatment, requiring intensive care unit (ICU) support, and another developed a catecholamine crisis 3 days after treatment, requiring hospitalization. The treatment protocols at our institution were subsequently modified by increasing the radioisotope infusion time from 15 to 30 min, as recommended in the literature, to 2–4 h and by reducing the administered dose of 177 Lu-DOTATATE. Subsequent 177 Lu-DOTATATE treatments utilizing the modified protocols were well tolerated, and response to therapy was achieved in all three patients, resulting in significantly improved quality of life. 177 Lu-DOTATATE is an exciting new therapeutic option in the management of paragangliomas; however, current treatment protocols described in the literature may need to be modified by lengthening the infusion time and/or lowering the initial treatment dose to prevent or reduce the severity of adverse reactions

  18. The challenges of treating paraganglioma patients with {sup 177}Lu-DOTATATE PRRT: Catecholamine crises, tumor lysis syndrome and the need for modification of treatment protocols

    Energy Technology Data Exchange (ETDEWEB)

    Makis, William; Mccann, Karey; Mcewan, Alexander J. B. [Dept. of Diagnostic Imaging, Cross Cancer Institute, Alberta (China)

    2015-09-15

    A high percentage of paragangliomas express somatostatin receptors that can be utilized for targeted radioisotope therapy. The aim of this study was to describe and discuss the challenges of treating these tumors with {sup 177}Lu-[DOTA0,Tyr3]octreotate (DOTATATE) radioisotope therapy using established protocols. Three paraganglioma patients were treated with 4–5 cycles of {sup 177}Lu-DOTATATE and were evaluated for side effects and response to therapy. Two of the three patients developed severe adverse reactions following their first {sup 177}Lu-DOTATATE treatment. One patient developed a catecholamine crisis and tumor lysis syndrome within hours of treatment, requiring intensive care unit (ICU) support, and another developed a catecholamine crisis 3 days after treatment, requiring hospitalization. The treatment protocols at our institution were subsequently modified by increasing the radioisotope infusion time from 15 to 30 min, as recommended in the literature, to 2–4 h and by reducing the administered dose of {sup 177}Lu-DOTATATE. Subsequent {sup 177}Lu-DOTATATE treatments utilizing the modified protocols were well tolerated, and response to therapy was achieved in all three patients, resulting in significantly improved quality of life. {sup 177}Lu-DOTATATE is an exciting new therapeutic option in the management of paragangliomas; however, current treatment protocols described in the literature may need to be modified by lengthening the infusion time and/or lowering the initial treatment dose to prevent or reduce the severity of adverse reactions.

  19. Relationship between laminin binding capacity and laminin expression on tumor cells sensitive or resistant to natural cell-mediated cytotoxicity

    International Nuclear Information System (INIS)

    Laybourn, K.A.; Varani, J.; Fligiel, S.E.G.; Hiserodt, J.C.

    1986-01-01

    Previous studies have identified the presence of laminin binding sites on murine NK and NC sensitive tumor cells by 125 I-laminin binding and laminin induced cell-cell aggregation. The finding that the addition of exogenous laminin inhibits NK/NC binding to sensitive tumor cells suggests laminin binding sites may serve as target antigens for NK cells. The present study extends earlier reports by analyzing a large panel of tumor cells for laminin binding capacity, laminin expression and sensitivity to NK/NC killing. The data indicate that all tumor cells which bind to NK/NC cells (8 lines tested) express laminin binding sites. All of these tumor cells were capable of competing for NK lysis of YAC-1 cells in cold target competition assays, and all bound enriched NK cells in direct single cell binding assays. In contrast, tumor cells expressing high levels of surface laminin (B16 melanomas, C57B1/6 fibrosarcomas, and RAS transfected 3T3 fibroblasts) but low levels of laminin binding capacity did not bind NK/NC cells and were resistant to lysis. These data support the hypothesis that expression of laminin/laminin binding sites may contribute to tumor cell sensitivity to NK/NC binding and/or killing

  20. MUC16 provides immune protection by inhibiting synapse formation between NK and ovarian tumor cells

    Directory of Open Access Journals (Sweden)

    Migneault Martine

    2010-01-01

    Full Text Available Abstract Background Cancer cells utilize a variety of mechanisms to evade immune detection and attack. Effective immune detection largely relies on the formation of an immune synapse which requires close contact between immune cells and their targets. Here, we show that MUC16, a heavily glycosylated 3-5 million Da mucin expressed on the surface of ovarian tumor cells, inhibits the formation of immune synapses between NK cells and ovarian tumor targets. Our results indicate that MUC16-mediated inhibition of immune synapse formation is an effective mechanism employed by ovarian tumors to evade immune recognition. Results Expression of low levels of MUC16 strongly correlated with an increased number of conjugates and activating immune synapses between ovarian tumor cells and primary naïve NK cells. MUC16-knockdown ovarian tumor cells were more susceptible to lysis by primary NK cells than MUC16 expressing controls. This increased lysis was not due to differences in the expression levels of the ligands for the activating receptors DNAM-1 and NKG2D. The NK cell leukemia cell line (NKL, which does not express KIRs but are positive for DNAM-1 and NKG2D, also conjugated and lysed MUC16-knockdown cells more efficiently than MUC16 expressing controls. Tumor cells that survived the NKL challenge expressed higher levels of MUC16 indicating selective lysis of MUC16low targets. The higher csMUC16 levels on the NKL resistant tumor cells correlated with more protection from lysis as compared to target cells that were never exposed to the effectors. Conclusion MUC16, a carrier of the tumor marker CA125, has previously been shown to facilitate ovarian tumor metastasis and inhibits NK cell mediated lysis of tumor targets. Our data now demonstrates that MUC16 expressing ovarian cancer cells are protected from recognition by NK cells. The immune protection provided by MUC16 may lead to selective survival of ovarian cancer cells that are more efficient in

  1. Extraction of Active Enzymes from "Hard-to-Break-Cells"

    DEFF Research Database (Denmark)

    Ottaviani, Alessio; Tesauro, Cinzia; Fjelstrup, S

    We present the utilization of a rolling circle amplification (RCA) based assay to investigate the extraction efficiency of active enzymes from a class of “hard-to-break” cells, yeast Saccaramyces cerevisiae. Current analyses of microorganisms, such as pathogenic bacteria, parasites or particular...... life stages of microorganisms (e.g. spores from bacteria or fungi) is hampered by the lack of efficient lysis protocols that preserve the activity and integrity of the cellular content. Presented herein is a flexible scheme to screen lysis protocols for active enzyme extraction. We also report a gentle...... yet effective approach for extraction of active enzymes by entrapping cells in microdroplets. Combined effort of optimized extraction protocols and effective analytical approaches is expected to generate impact in future disease diagnosis and environmental safety....

  2. Fate of deposited cells in an aerobic binary bacterial biofilm

    International Nuclear Information System (INIS)

    Banks, M.K.

    1989-01-01

    A biofilm is a matrix of microbial cells and their extracellular products that is associated with a solid surface. Previous studies on biofilm development have employed only dissolved compounds as growth limiting substrates, without the influence of microbial species invading from the bulk liquid. The goal of this research project was to quantify the kinetics of processes governing suspended biomass turnover in biofilm systems, and the accompanying effects of suspended cell deposition on biofilm population dynamics. Experiments were conducted with two species of bacteria, Pseudomonas putida ATCC 11172 grown on glucose, and Hyphomicrobium ZV620 grown on methanol. Cryptic growth and particulate hydrolysis studies were evaluated, using combinations of these two bacteria, by measuring the uptake of radiolabelled cell lysis products, under batch conditions. Biofilms studies were performed to investigate bacterial deposition, continual biofilm removal by shear induced erosion, and biofilm ecology. Biofilms were developed in a flow cell reactor, under laminar flow conditions. Bacterial species were differentiated by radioactively labelling each species with their carbon substrate. A mathematical model was developed to predict the biofilm ecology of mixed cultures. The equations developed predict biofilm accumulation, as well as substrate and oxygen consumption. Results indicate that cryptic growth will occur for bacteria growing on their own species soluble lysis products and in some cases, bacteria growing on the soluble lysis products of other species. Particulate hydrolysis only occurred for Pseudomonas putida growing on Pseudomonas putida lysis products, but the lack of particulate hydrolysis occurring in the other studies may have been due to the short experimental period

  3. Molecular dosimetry of DNA damage caused by alkylation. I. Single-strand breaks induced by ethylating agents in cultured mammalian cells in relation to survival

    NARCIS (Netherlands)

    Abbondandolo, A.; Dogliotti, E.; Lohman, P.H.M.; Berends, F.

    1982-01-01

    Cultured Chinese hamster ovary cells were treated with ethylating agents. DNA lesions giving rise to single-strand breaks (ssb) or alkali-labile sites were measured by centrifugation in alkaline sucrose gradients after lysis in alkali. 4 agents with different tendencies to ethylate preferentially

  4. Mycelium differentiation and development of Streptomyces coelicolor in lab-scale bioreactors: Programmed cell death, differentiation, and lysis are closely linked to undecylprodigiosin and actinorhodin production

    OpenAIRE

    Rioseras de Bustos, Beatriz; López García, María Teresa (Bio); Yagüe Menéndez, Paula; Sánchez Martín, Jesús; Manteca Fernández, Ángel

    2014-01-01

    Streptomycetes are mycelium-forming bacteria that produce two thirds of clinically relevant secondary metabolites. Secondary metabolite production is activated at specific developmental stages of Streptomyces life cycle. Despite this, Streptomyces differentiation in industrial bioreactors tends to be underestimated and the most important parameters managed are only indirectly related to differentiation: modifications to the culture media, optimization of productive strains by random or direct...

  5. Addition of a sequence from α2-antiplasmin transforms human serum albumin into a blood clot component that speeds clot lysis

    Directory of Open Access Journals (Sweden)

    Gataiance Sharon

    2009-03-01

    Full Text Available Abstract Background The plasma protein α2-antiplasmin (α2AP is cross-linked to fibrin in blood clots by the transglutaminase factor XIIIa, and in that location retards clot lysis. Competition for this effect could be clinically useful in patients with thrombosis. We hypothesized that fusion of N-terminal portions of α2-antiplasmin to human serum albumin (HSA and production of the chimeric proteins in Pichia pastoris yeast would produce a stable and effective competitor protein. Results Fusion protein α2AP(13-42-HSA was efficiently secreted from transformed yeast and purified preparations contained within a mixed population the full-length intact form, while fusions with longer α2AP moieties were inefficiently secreted and/or degraded. The α2AP(13-42-HSA protein, but not recombinant HSA, was cross-linked to both chemical lysine donors and fibrin or fibrinogen by factor XIIIa, although with less rapid kinetics than native α2AP. Excess α2AP(13-42-HSA competed with α2AP for cross-linking to chemical lysine donors more effectively than a synthetic α2AP(13-42 peptide, and reduced the α2AP-dependent resistance to fibrinolysis of plasma clots equally effectively as the peptide. Native α2AP was found in in vivo clots in rabbits to a greater extent than α2AP(13-42, however. Conclusion In this first report of transfer of transglutamination substrate status from one plasma protein to another, fusion protein α2AP(13-42-HSA was shown to satisfy initial requirements for a long-lasting, well-tolerated competitive inhibitor of α2-antiplasmin predicted to act in a clot-localized manner.

  6. Using SPIRAL (Single Pollen Isotope Ratio AnaLysis) to estimate C 3- and C 4-grass abundance in the paleorecord

    Science.gov (United States)

    Nelson, David M.; Hu, Feng Sheng; Scholes, Daniel R.; Joshi, Neeraj; Pearson, Ann

    2008-05-01

    C 3 and C 4 grasses differ greatly in their responses to environmental controls and influences on biogeochemical processes (e.g. water, carbon, and nutrient cycling). Difficulties in distinguishing between these two functional groups of grasses have hindered paleoecological studies of grass-dominated ecosystems. Stable carbon isotopic analysis of individual grains of grass pollen using a spooling-wire microcombustion device interfaced with an isotope-ratio mass spectrometer holds promise for improving C 3 and C 4 grass reconstructions. This technique, SPIRAL (Single Pollen Isotope Ratio AnaLysis), has only been evaluated using pollen of known C 3 and C 4 grasses. To test the ability of SPIRAL to reproduce the abundance of C 3 and C 4 grasses on the landscape, we measured δ13C values of > 1500 individual grains of grass pollen isolated from the surface sediments of ten lakes in areas that span a large gradient of C 3- and C 4-grass abundance, as determined from vegetation surveys. Results indicate a strong positive correlation between the δ13C-based estimates of % C 4-grass pollen and the abundance of C 4 grasses on the landscape. The % C 4-grass pollen slightly underestimates the actual abundance of C 4 grasses at sites with high proportions of C 4 grasses, which can be corrected using regression analysis. Comparison of the % C 4-grass pollen with C/N and δ13C measurements of bulk organic matter illustrates the distinct advantages of grass-pollen δ13C as a proxy for distinguishing C 3 and C 4 shifts within the grass family. Thus SPIRAL promises to advance our understanding of grassland ecology and evolution.

  7. Performance assessment of two lysis methods for direct identification of yeasts from clinical blood cultures using MALDI-TOF mass spectrometry.

    Science.gov (United States)

    Jeddi, Fakhri; Yapo-Kouadio, Gisèle Cha; Normand, Anne-Cécile; Cassagne, Carole; Marty, Pierre; Piarroux, Renaud

    2017-02-01

    In cases of fungal infection of the bloodstream, rapid species identification is crucial to provide adapted therapy and thereby ameliorate patient outcome. Currently, the commercial Sepsityper kit and the sodium-dodecyl sulfate (SDS) method coupled with MALDI-TOF mass spectrometry are the most commonly reported lysis protocols for direct identification of fungi from positive blood culture vials. However, the performance of these two protocols has never been compared on clinical samples. Accordingly, we performed a two-step survey on two distinct panels of clinical positive blood culture vials to identify the most efficient protocol, establish an appropriate log score (LS) cut-off, and validate the best method. We first compared the performance of the Sepsityper and the SDS protocols on 71 clinical samples. For 69 monomicrobial samples, mass spectrometry LS values were significantly higher with the SDS protocol than with the Sepsityper method (P < .0001), especially when the best score of four deposited spots was considered. Next, we established the LS cut-off for accurate identification at 1.7, based on specimen DNA sequence data. Using this LS cut-off, 66 (95.6%) and 46 (66.6%) isolates were correctly identified at the species level with the SDS and the Sepsityper protocols, respectively. In the second arm of the survey, we validated the SDS protocol on an additional panel of 94 clinical samples. Ninety-two (98.9%) of 93 monomicrobial samples were correctly identified at the species level (median LS = 2.061). Overall, our data suggest that the SDS method yields more accurate species identification of yeasts, than the Sepsityper protocol. © The Author 2016. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. Suitability of small diagnostic peripheral-blood samples for cell-therapy studies.

    Science.gov (United States)

    Stephanou, Coralea; Papasavva, Panayiota; Zachariou, Myria; Patsali, Petros; Epitropou, Marilena; Ladas, Petros; Al-Abdulla, Ruba; Christou, Soteroulla; Antoniou, Michael N; Lederer, Carsten W; Kleanthous, Marina

    2017-02-01

    Primary hematopoietic stem and progenitor cells (HSPCs) are key components of cell-based therapies for blood disorders and are thus the authentic substrate for related research. We propose that ubiquitous small-volume diagnostic samples represent a readily available and as yet untapped resource of primary patient-derived cells for cell- and gene-therapy studies. In the present study we compare isolation and storage methods for HSPCs from normal and thalassemic small-volume blood samples, considering genotype, density-gradient versus lysis-based cell isolation and cryostorage media with different serum contents. Downstream analyses include viability, recovery, differentiation in semi-solid media and performance in liquid cultures and viral transductions. We demonstrate that HSPCs isolated either by ammonium-chloride potassium (ACK)-based lysis or by gradient isolation are suitable for functional analyses in clonogenic assays, high-level HSPC expansion and efficient lentiviral transduction. For cryostorage of cells, gradient isolation is superior to ACK lysis, and cryostorage in freezing media containing 50% fetal bovine serum demonstrated good results across all tested criteria. For assays on freshly isolated cells, ACK lysis performed similar to, and for thalassemic samples better than, gradient isolation, at a fraction of the cost and hands-on time. All isolation and storage methods show considerable variation within sample groups, but this is particularly acute for density gradient isolation of thalassemic samples. This study demonstrates the suitability of small-volume blood samples for storage and preclinical studies, opening up the research field of HSPC and gene therapy to any blood diagnostic laboratory with corresponding bioethics approval for experimental use of surplus material. Copyright © 2017 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

  9. Biosynthesis of silver nanoparticle and its application in cell wall disruption to release carbohydrate and lipid from C. vulgaris for biofuel production

    Directory of Open Access Journals (Sweden)

    Sirajunnisa Abdul Razack

    2016-09-01

    Full Text Available Microalgae are the fledging feedstocks yielding raw materials for the production of third generation biofuel. Assorted and conventional cell wall disruption techniques were helpful in extracting lipids and carbohydrates, nevertheless the disadvantages have led the biotechnologists to explore new process to lyse cell wall in a faster and an economical manner. Silver nanoparticles have the ability to break the cell wall of microalgae and release biomolecules effectively. Green synthesis of silver nanoparticles was performed using a novel bacterial isolate of Bacillus subtilis. Characterisation of nanosilver and its effect on cell wall lysis of microalgae were extensively analysed. Cell wall damage was confirmed by lactate dehydrogenase assay and visually by SEM analysis. This first piece of research work on direct use of nanoparticles for cell wall lysis would potentially be advantageous over its conventional approaches and a greener, cost effective and non laborious method for the production of biodiesel.

  10. Altered effector function of peripheral cytotoxic cells in COPD

    Directory of Open Access Journals (Sweden)

    Corne Jonathan M

    2009-06-01

    Full Text Available Abstract Background There is mounting evidence that perforin and granzymes are important mediators in the lung destruction seen in COPD. We investigated the characteristics of the three main perforin and granzyme containing peripheral cells, namely CD8+ T lymphocytes, natural killer (NK; CD56+CD3- cells and NKT-like (CD56+CD3+ cells. Methods Peripheral blood mononuclear cells (PBMCs were isolated and cell numbers and intracellular granzyme B and perforin were analysed by flow cytometry. Immunomagnetically selected CD8+ T lymphocytes, NK (CD56+CD3- and NKT-like (CD56+CD3+ cells were used in an LDH release assay to determine cytotoxicity and cytotoxic mechanisms were investigated by blocking perforin and granzyme B with relevant antibodies. Results The proportion of peripheral blood NKT-like (CD56+CD3+ cells in smokers with COPD (COPD subjects was significantly lower (0.6% than in healthy smokers (smokers (2.8%, p +CD3- cells from COPD subjects were significantly less cytotoxic than in smokers (16.8% vs 51.9% specific lysis, p +CD3+ cells (16.7% vs 52.4% specific lysis, p +CD3- and NKT-like (CD56+CD3+ cells from smokers and HNS. Conclusion In this study, we show that the relative numbers of peripheral blood NK (CD56+CD3- and NKT-like (CD56+CD3+ cells in COPD subjects are reduced and that their cytotoxic effector function is defective.

  11. Bacterial Cell Mechanics.

    Science.gov (United States)

    Auer, George K; Weibel, Douglas B

    2017-07-25

    Cellular mechanical properties play an integral role in bacterial survival and adaptation. Historically, the bacterial cell wall and, in particular, the layer of polymeric material called the peptidoglycan were the elements to which cell mechanics could be primarily attributed. Disrupting the biochemical machinery that assembles the peptidoglycan (e.g., using the β-lactam family of antibiotics) alters the structure of this material, leads to mechanical defects, and results in cell lysis. Decades after the discovery of peptidoglycan-synthesizing enzymes, the mechanisms that underlie their positioning and regulation are still not entirely understood. In addition, recent evidence suggests a diverse group of other biochemical elements influence bacterial cell mechanics, may be regulated by new cellular mechanisms, and may be triggered in different environmental contexts to enable cell adaptation and survival. This review summarizes the contributions that different biomolecular components of the cell wall (e.g., lipopolysaccharides, wall and lipoteichoic acids, lipid bilayers, peptidoglycan, and proteins) make to Gram-negative and Gram-positive bacterial cell mechanics. We discuss the contribution of individual proteins and macromolecular complexes in cell mechanics and the tools that make it possible to quantitatively decipher the biochemical machinery that contributes to bacterial cell mechanics. Advances in this area may provide insight into new biology and influence the development of antibacterial chemotherapies.

  12. Immunobiology of T cell responses to Mls-locus-disparate stimulator cells. III. Helper and cytolytic functions of cloned, Mls-reactive T cell lines

    International Nuclear Information System (INIS)

    Katz, M.E.; Tite, J.P.; Janeway, C.A. Jr.

    1986-01-01

    Mls-specific T cell clones derived by limiting dilution were tested for cytotoxic activity in a lectin-dependent 51 Cr-release assay. All the T cell clones tested were cytotoxic in such an assay in apparent contrast to previous reports (1, 2). However, only those target cells sensitive to cytolysis by other L3T4a + cytolytic T cells (3) were killed by Mls-specific T cell clones in short term 51 Cr-release assays, possibly explaining this discrepancy. All the T cell clones tested were L3T4a + ,Lyt-2 - and stimulated B cells from Mls strains of mice to proliferate and secrete immunoglobulin. Furthermore, lysis of innocent bystander targets was observed when the T cells were stimulated with Mls-disparate stimulator cells. These results are consistent with those obtained with L3T4a - T cells specific for protein antigen:self Ia and that express cytotoxic potential (3)

  13. Same day identification and full panel antimicrobial susceptibility testing of bacteria from positive blood culture bottles made possible by a combined lysis-filtration method with MALDI-TOF VITEK mass spectrometry and the VITEK2 system.

    Directory of Open Access Journals (Sweden)

    Alexandra Machen

    Full Text Available Rapid identification and antimicrobial susceptibility testing of microorganisms causing bloodstream infections or sepsis have the potential to improve patient care. This proof-of-principle study evaluates the Lysis-Filtration Method for identification as well as antimicrobial susceptibility testing of bacteria directly from positive blood culture bottles in a clinical setting. A total of 100 non-duplicated positive blood cultures were tested and 1012 microorganism-antimicrobial combinations were assessed. An aliquot of non-charcoal blood culture broth was incubated with lysis buffer briefly before being filtered and washed. Microorganisms recovered from the filter membrane were first identified by using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight VITEK® Mass Spectrometry (VITEK MS. After quick identification from VITEK MS, filtered microorganisms were inoculated to VITEK®2 system for full panel antimicrobial susceptibility testing analysis. Of 100 bottles tested, the VITEK MS resulted in 94.0% correct organism identification to the species level. Compared to the conventional antimicrobial susceptibility testing methods, direct antimicrobial susceptibility testing from VITEK®2 resulted in 93.5% (946/1012 category agreement of antimicrobials tested, with 3.6% (36/1012 minor error, 1.7% (7/1012 major error, and 1.3% (13/1012 very major error of antimicrobials. The average time to identification and antimicrobial susceptibility testing was 11.4 hours by using the Lysis-Filtration method for both VITEK MS and VITEK®2 compared to 56.3 hours by using conventional methods (p<0.00001. Thus, the same-day results of microorganism identification and antimicrobial susceptibility testing directly from positive blood culture can be achieved and can be used for appropriate antibiotic therapy and antibiotic stewardship.

  14. Same Day Identification and Full Panel Antimicrobial Susceptibility Testing of Bacteria from Positive Blood Culture Bottles Made Possible by a Combined Lysis-Filtration Method with MALDI-TOF VITEK Mass Spectrometry and the VITEK2 System

    Science.gov (United States)

    Machen, Alexandra; Drake, Tim; Wang, Yun F. (Wayne)

    2014-01-01

    Rapid identification and antimicrobial susceptibility testing of microorganisms causing bloodstream infections or sepsis have the potential to improve patient care. This proof-of-principle study evaluates the Lysis-Filtration Method for identification as well as antimicrobial susceptibility testing of bacteria directly from positive blood culture bottles in a clinical setting. A total of 100 non-duplicated positive blood cultures were tested and 1012 microorganism-antimicrobial combinations were assessed. An aliquot of non-charcoal blood culture broth was incubated with lysis buffer briefly before being filtered and washed. Microorganisms recovered from the filter membrane were first identified by using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight VITEK® Mass Spectrometry (VITEK MS). After quick identification from VITEK MS, filtered microorganisms were inoculated to VITEK®2 system for full panel antimicrobial susceptibility testing analysis. Of 100 bottles tested, the VITEK MS resulted in 94.0% correct organism identification to the species level. Compared to the conventional antimicrobial susceptibility testing methods, direct antimicrobial susceptibility testing from VITEK®2 resulted in 93.5% (946/1012) category agreement of antimicrobials tested, with 3.6% (36/1012) minor error, 1.7% (7/1012) major error, and 1.3% (13/1012) very major error of antimicrobials. The average time to identification and antimicrobial susceptibility testing was 11.4 hours by using the Lysis-Filtration method for both VITEK MS and VITEK®2 compared to 56.3 hours by using conventional methods (p<0.00001). Thus, the same-day results of microorganism identification and antimicrobial susceptibility testing directly from positive blood culture can be achieved and can be used for appropriate antibiotic therapy and antibiotic stewardship. PMID:24551067

  15. Same day identification and full panel antimicrobial susceptibility testing of bacteria from positive blood culture bottles made possible by a combined lysis-filtration method with MALDI-TOF VITEK mass spectrometry and the VITEK2 system.

    Science.gov (United States)

    Machen, Alexandra; Drake, Tim; Wang, Yun F Wayne

    2014-01-01

    Rapid identification and antimicrobial susceptibility testing of microorganisms causing bloodstream infections or sepsis have the potential to improve patient care. This proof-of-principle study evaluates the Lysis-Filtration Method for identification as well as antimicrobial susceptibility testing of bacteria directly from positive blood culture bottles in a clinical setting. A total of 100 non-duplicated positive blood cultures were tested and 1012 microorganism-antimicrobial combinations were assessed. An aliquot of non-charcoal blood culture broth was incubated with lysis buffer briefly before being filtered and washed. Microorganisms recovered from the filter membrane were first identified by using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight VITEK® Mass Spectrometry (VITEK MS). After quick identification from VITEK MS, filtered microorganisms were inoculated to VITEK®2 system for full panel antimicrobial susceptibility testing analysis. Of 100 bottles tested, the VITEK MS resulted in 94.0% correct organism identification to the species level. Compared to the conventional antimicrobial susceptibility testing methods, direct antimicrobial susceptibility testing from VITEK®2 resulted in 93.5% (946/1012) category agreement of antimicrobials tested, with 3.6% (36/1012) minor error, 1.7% (7/1012) major error, and 1.3% (13/1012) very major error of antimicrobials. The average time to identification and antimicrobial susceptibility testing was 11.4 hours by using the Lysis-Filtration method for both VITEK MS and VITEK®2 compared to 56.3 hours by using conventional methods (pdirectly from positive blood culture can be achieved and can be used for appropriate antibiotic therapy and antibiotic stewardship.

  16. Secretome Analysis of Lipid-Induced Insulin Resistance in Skeletal Muscle Cells by a Combined Experimental and Bioinformatics Workflow

    DEFF Research Database (Denmark)

    Deshmukh, Atul S; Cox, Juergen; Jensen, Lars Juhl

    2015-01-01

    , in principle, allows an unbiased and comprehensive analysis of cellular secretomes; however, the distinction of bona fide secreted proteins from proteins released upon lysis of a small fraction of dying cells remains challenging. Here we applied highly sensitive MS and streamlined bioinformatics to analyze......-resistant conditions. Our study demonstrates an efficient combined experimental and bioinformatics workflow to identify putative secreted proteins from insulin-resistant skeletal muscle cells, which could easily be adapted to other cellular models....

  17. Rapid Extraction of Genomic DNA from Medically Important Yeasts and Filamentous Fungi by High-Speed Cell Disruption

    OpenAIRE

    Müller, Frank-Michael C.; Werner, Katherine E.; Kasai, Miki; Francesconi, Andrea; Chanock, Stephen J.; Walsh, Thomas J.

    1998-01-01

    Current methods of DNA extraction from different fungal pathogens are often time-consuming and require the use of toxic chemicals. DNA isolation from some fungal organisms is difficult due to cell walls or capsules that are not readily susceptible to lysis. We therefore investigated a new and rapid DNA isolation method using high-speed cell disruption (HSCD) incorporating chaotropic reagents and lysing matrices in comparison to standard phenol-chloroform (PC) extraction protocols for isolatio...

  18. Rapid Detection and Identification of Candidemia by Direct Blood Culturing on Solid Medium by Use of Lysis-Centrifugation Method Combined with Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry (MALDI-TOF MS)

    Science.gov (United States)

    Idelevich, Evgeny A.; Grünastel, Barbara

    2016-01-01

    ABSTRACT Candida sepsis is a life-threatening condition with increasing prevalence. In this study, direct blood culturing on solid medium using a lysis-centrifugation procedure enabled successful Candida species identification by matrix-assisted laser desorption–ionization time of flight mass spectrometry on average 3.8 h (Sabouraud agar) or 7.4 h (chocolate agar) before the positivity signal for control samples in Bactec mycosis-IC/F or Bactec Plus aerobic/F bottles, respectively. Direct culturing on solid medium accelerated candidemia diagnostics compared to that with automated broth-based systems. PMID:27795344

  19. Rapid Detection and Identification of Candidemia by Direct Blood Culturing on Solid Medium by Use of Lysis-Centrifugation Method Combined with Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS).

    Science.gov (United States)

    Idelevich, Evgeny A; Grünastel, Barbara; Becker, Karsten

    2017-01-01

    Candida sepsis is a life-threatening condition with increasing prevalence. In this study, direct blood culturing on solid medium using a lysis-centrifugation procedure enabled successful Candida species identification by matrix-assisted laser desorption-ionization time of flight mass spectrometry on average 3.8 h (Sabouraud agar) or 7.4 h (chocolate agar) before the positivity signal for control samples in Bactec mycosis-IC/F or Bactec Plus aerobic/F bottles, respectively. Direct culturing on solid medium accelerated candidemia diagnostics compared to that with automated broth-based systems. Copyright © 2016 American Society for Microbiology.

  20. Interactions between human mesenchymal stem cells and natural killer cells.

    Science.gov (United States)

    Sotiropoulou, Panagiota A; Perez, Sonia A; Gritzapis, Angelos D; Baxevanis, Constantin N; Papamichail, Michael

    2006-01-01

    Mesenchymal stem cells (MSCs) are multipotent progenitor cells representing an attractive therapeutic tool for regenerative medicine. They possess unique immunomodulatory properties, being capable of suppressing T-cell responses and modifying dendritic cell differentiation, maturation, and function, whereas they are not inherently immunogenic, failing to induce alloreactivity to T cells and freshly isolated natural killer (NK) cells. To clarify the generation of host immune responses to implanted MSCs in tissue engineering and their potential use as immunosuppressive elements, the effect of MSCs on NK cells was investigated. We demonstrate that at low NK-to-MSC ratios, MSCs alter the phenotype of NK cells and suppress proliferation, cytokine secretion, and cyto-toxicity against HLA-class I- expressing targets. Some of these effects require cell-to-cell contact, whereas others are mediated by soluble factors, including transforming growth factor-beta1 and prostaglandin E2, suggesting the existence of diverse mechanisms for MSC-mediated NK-cell suppression. On the other hand, MSCs are susceptible to lysis by activated NK cells. Overall, these data improve our knowledge of interactions between MSCs and NK cells and consequently of their effect on innate immune responses and their contribution to the regulation of adaptive immunity, graft rejection, and cancer immunotherapy.

  1. Impact of Diverse Immune Evasion Mechanisms of Cancer Cells on T Cells Engaged by EpCAM/CD3-Bispecific Antibody Construct AMG 110

    Science.gov (United States)

    Deisting, Wibke; Raum, Tobias; Kufer, Peter; Baeuerle, Patrick A.; Münz, Markus

    2015-01-01

    Background Bispecific T cell engager (BiTE®) are single-chain bispecific antibody constructs with dual specificity for CD3 on T cells and a surface antigen on target cells. They can elicit a polyclonal cytotoxic T cell response that is not restricted by T cell receptor (TCR) specificity, and surface expression of MHC class I/peptide antigen complexes. Using human EpCAM/CD3-bispecific BiTE® antibody construct AMG 110, we here assessed to what extent surface expression of PD-L1, cytoplasmic expression of indoleamine-2,3-deoxygenase type 1, Bcl-2 and serpin PI-9, and the presence of transforming growth factor beta (TGF-β), interleukin-10 (IL-10) and adenosine in culture medium can impact redirected lysis by AMG 110-engaged T cells. Methods The seven factors, which are all involved in inhibiting T cell functions by cancer cells, were tested with human EpCAM-expressing Chinese hamster ovary (CHO) target cells at levels that in most cases exceeded those observed in a number of human cancer cell lines. Co-culture experiments were used to determine the impact of the evasion mechanisms on EC50 values and amplitude of redirected lysis by AMG 110, and on BiTE®-induced proliferation of previously resting human peripheral T cells. Findings An inhibitory effect on redirected lysis by AMG 110-engaged T cells was seen upon overexpression of serpin PI-9, Bcl-2, TGF-βand PD-L1. An inhibitory effect on induction of T cell proliferation was only seen with CHO cells overexpressing IDO. In no case, a single evasion mechanism rendered target cells completely resistant to BiTE®-induced lysis, and even various combinations could not. Conclusions Our data suggest that diverse mechanisms employed by cancer cells to fend off T cells cannot inactivate AMG 110-engaged T cells, and that inhibitory effects observed in vitro may be overcome by increased concentrations of the BiTE® antibody construct. PMID:26510188

  2. Impact of Diverse Immune Evasion Mechanisms of Cancer Cells on T Cells Engaged by EpCAM/CD3-Bispecific Antibody Construct AMG 110.

    Directory of Open Access Journals (Sweden)

    Wibke Deisting

    Full Text Available Bispecific T cell engager (BiTE® are single-chain bispecific antibody constructs with dual specificity for CD3 on T cells and a surface antigen on target cells. They can elicit a polyclonal cytotoxic T cell response that is not restricted by T cell receptor (TCR specificity, and surface expression of MHC class I/peptide antigen complexes. Using human EpCAM/CD3-bispecific BiTE® antibody construct AMG 110, we here assessed to what extent surface expression of PD-L1, cytoplasmic expression of indoleamine-2,3-deoxygenase type 1, Bcl-2 and serpin PI-9, and the presence of transforming growth factor beta (TGF-β, interleukin-10 (IL-10 and adenosine in culture medium can impact redirected lysis by AMG 110-engaged T cells.The seven factors, which are all involved in inhibiting T cell functions by cancer cells, were tested with human EpCAM-expressing Chinese hamster ovary (CHO target cells at levels that in most cases exceeded those observed in a number of human cancer cell lines. Co-culture experiments were used to determine the impact of the evasion mechanisms on EC50 values and amplitude of redirected lysis by AMG 110, and on BiTE®-induced proliferation of previously resting human peripheral T cells.An inhibitory effect on redirected lysis by AMG 110-engaged T cells was seen upon overexpression of serpin PI-9, Bcl-2, TGF-β and PD-L1. An inhibitory effect on induction of T cell proliferation was only seen with CHO cells overexpressing IDO. In no case, a single evasion mechanism rendered target cells completely resistant to BiTE®-induced lysis, and even various combinations could not.Our data suggest that diverse mechanisms employed by cancer cells to fend off T cells cannot inactivate AMG 110-engaged T cells, and that inhibitory effects observed in vitro may be overcome by increased concentrations of the BiTE® antibody construct.

  3. A potential therapy for chordoma via antibody-dependent cell-mediated cytotoxicity employing NK or high-affinity NK cells in combination with cetuximab.

    Science.gov (United States)

    Fujii, Rika; Schlom, Jeffrey; Hodge, James W

    2018-05-01

    OBJECTIVE Chordoma is a rare bone tumor derived from the notochord and is resistant to conventional therapies such as chemotherapy, radiotherapy, and targeting therapeutics. Expression of epidermal growth factor receptor (EGFR) in a large proportion of chordoma specimens indicates a potential target for therapeutic intervention. In this study the authors investigated the potential role of the anti-EGFR antibody cetuximab in immunotherapy for chordoma. METHODS Since cetuximab is a monoclonal antibody of the IgG1 isotype, it has the potential to mediate antibody-dependent cell-mediated cytotoxicity (ADCC) employing natural killer (NK) cells as effectors. Polymorphisms in the CD16 allele expressed on NK cells have been shown to influence the degree of ADCC of tumor cells, with the high-affinity valine (V)/V allele being responsible for more lysis than the V/phenylalanine (F) or FF allele. Unfortunately, however, only approximately 10% of the population expresses the VV allele on NK cells. An NK cell line, NK-92, has now been engineered to endogenously express IL-2 and the high-affinity CD16 allele. These irradiated high-affinity (ha)NK cells were analyzed for lysis of chordoma cells with and without cetuximab, and the levels of lysis observed in ADCC were compared with those of NK cells from donors expressing the VV, VF, and FF alleles. RESULTS Here the authors demonstrate for the first time 1) that cetuximab in combination with NK cells can mediate ADCC of chordoma cells; 2) the influence of the NK CD16 polymorphism in cetuximab-mediated ADCC for chordoma cell lysis; 3) that engineered haNK cells-that is, cells transduced to express the CD16 V158 FcγRIIIa receptor-bind cetuximab with similar affinity to normal NK cells expressing the high-affinity VV allele; and 4) that irradiated haNK cells induce ADCC with cetuximab in chordoma cells. CONCLUSIONS These studies provide rationale for the use of cetuximab in combination with irradiated haNK cells for therapy for

  4. Cell death in Pseudomonas aeruginosa biofilm development

    DEFF Research Database (Denmark)

    Webb, J.S.; Thompson, L.S.; James, S.

    2003-01-01

    Bacteria growing in biofilms often develop multicellular, three-dimensional structures known as microcolonies. Complex differentiation within biofilms of Pseudomonas aeruginosa occurs, leading to the creation of voids inside microcolonies and to the dispersal of cells from within these voids....... However, key developmental processes regulating these events are poorly understood. A normal component of multicellular development is cell death. Here we report that a repeatable pattern of cell death and lysis occurs in biofilms of P. aeruginosa during the normal course of development. Cell death...... occurred with temporal and spatial organization within biofilms, inside microcolonies, when the biofilms were allowed to develop in continuous-culture flow cells. A subpopulation of viable cells was always observed in these regions. During the onset of biofilm killing and during biofilm development...

  5. A microfluidic chip for direct and rapid trapping of white blood cells from whole blood

    Science.gov (United States)

    Chen, Jingdong; Chen, Di; Yuan, Tao; Xie, Yao; Chen, Xiang

    2013-01-01

    Blood analysis plays a major role in medical and science applications and white blood cells (WBCs) are an important target of analysis. We proposed an integrated microfluidic chip for direct and rapid trapping WBCs from whole blood. The microfluidic chip consists of two basic functional units: a winding channel to mix and arrays of two-layer trapping structures to trap WBCs. Red blood cells (RBCs) were eliminated through moving the winding channel and then WBCs were trapped by the arrays of trapping structures. We fabricated the PDMS (polydimethylsiloxane) chip using soft lithography and determined the critical flow velocities of tartrazine and brilliant blue water mixing and whole blood and red blood cell lysis buffer mixing in the winding channel. They are 0.25 μl/min and 0.05 μl/min, respectively. The critical flow velocity of the whole blood and red blood cell lysis buffer is lower due to larger volume of the RBCs and higher kinematic viscosity of the whole blood. The time taken for complete lysis of whole blood was about 85 s under the flow velocity 0.05 μl/min. The RBCs were lysed completely by mixing and the WBCs were trapped by the trapping structures. The chip trapped about 2.0 × 103 from 3.3 × 103 WBCs. PMID:24404026

  6. Antibody-Dependent Cellular Cytotoxicity Activity of a Novel Anti-PD-L1 Antibody Avelumab (MSB0010718C) on Human Tumor Cells.

    Science.gov (United States)

    Boyerinas, Benjamin; Jochems, Caroline; Fantini, Massimo; Heery, Christopher R; Gulley, James L; Tsang, Kwong Yok; Schlom, Jeffrey

    2015-10-01

    Several anti-PD-1/PD-L1 monoclonal antibodies (mAb) are currently providing evidence of clinical benefit in subsets of cancer patients. The mode of action of these mAbs is to inhibit PD-1 on immune cells interacting with PD-L1 on tumor cells. These mAbs are either designed or engineered to eliminate antibody-dependent cell-mediated cytotoxicity (ADCC), which, however, has been implicated as an important mechanism in several highly effective mAb-mediated cancer therapies. A fully human anti-PD-L1 mAb would potentially be able to block PD-1/PD-L1 interactions and also mediate the ADCC lysis of tumor cells. MSB0010718C (designated avelumab) is a fully human IgG1 anti-PD-L1 mAb. The studies reported here demonstrate (i) the ability of avelumab to lyse a range of human tumor cells in the presence of PBMC or NK effectors; (ii) IFNγ can enhance tumor cell PD-L1 expression and, in some cases, enhance ADCC tumor cell lysis; (iii) purified NK cells are potent effectors for avelumab; (iv) similar levels of avelumab-mediated ADCC lysis of tumor cells are seen using purified NK as effectors from either healthy donors or cancer patients; (v) very low levels of avelumab-mediated lysis are seen using whole PBMCs as targets; this finding complements results seen in analyses of PBMC subsets of patients receiving avelumab; and (vi) the addition of IL12 to NK cells greatly enhances avelumab-mediated ADCC. These studies thus provide an additional mode of action for an anti-PD-L1 mAb and support the rationale for further studies to enhance avelumab-mediated ADCC activity. ©2015 American Association for Cancer Research.

  7. Antibody-dependent cellular cytotoxicity (ADCC) activity of a novel anti-PD-L1 antibody avelumab (MSB0010718C) on human tumor cells

    Science.gov (United States)

    Fantini, Massimo; Heery, Christopher R.; Gulley, James L.; Tsang, Kwong Yok; Schlom, Jeffrey

    2015-01-01

    Several anti-PD1/PD-L1 monoclonal antibodies (MAb) are currently providing evidence of clinical benefit in subsets of cancer patients. The mode of action of these MAbs is to inhibit PD1 on immune cells interacting with PD-L1 on tumor cells. These MAbs are either designed or engineered to eliminate antibody-dependent cell-mediated cytotoxicity (ADCC), which, however, has been implicated as an important mechanism in several highly effective MAb-mediated cancer therapies. A fully human anti-PD-L1 MAb would potentially be able to block PD-L1/PD1 interactions and also mediate the ADCC lysis of tumor cells. MSB0010718C (designated avelumab) is a fully human IgG1 anti-PD-L1 MAb. The studies reported here demonstrate (a) the ability of avelumab to lyse a range of human tumor cells in the presence of PBMC or NK effectors; (b) IFNγ can enhance tumor cell PD-L1 expression and in some cases enhance ADCC tumor cell lysis; (c) purified NK cells are potent effectors for avelumab; (d) similar levels of avelumab-mediated ADCC lysis of tumor cells are seen using purified NK as effectors from either healthy donors or cancer patients; (e) very low levels of avelumab-mediated lysis are seen using whole PBMCs as targets; this finding complements results seen in analyses of PBMC subsets of patients receiving avelumab; and (f) the addition of IL12 to NK cells greatly enhances avelumab-mediated ADCC. These studies thus provide an additional mode of action for an anti-PD-L1 MAb and support the rationale for further studies to enhance avelumab-mediated ADCC activity. PMID:26014098

  8. Adoptive cancer immunotherapy using DNA-demethylated T helper cells as antigen-presenting cells

    DEFF Research Database (Denmark)

    Kirkin, Alexei F.; Dzhandzhugazyan, Karine N.; Guldberg, Per

    2018-01-01

    In cancer cells, cancer/testis (CT) antigens become epigenetically derepressed through DNA demethylation and constitute attractive targets for cancer immunotherapy. Here we report that activated CD4+ T helper cells treated with a DNA-demethylating agent express a broad repertoire of endogenous CT...... antigens and can be used as antigen-presenting cells to generate autologous cytotoxic T lymphocytes (CTLs) and natural killer cells. In vitro, activated CTLs induce HLA-restricted lysis of tumor cells of different histological types, as well as cells expressing single CT antigens. In a phase 1 trial of 25...... patients with recurrent glioblastoma multiforme, cytotoxic lymphocytes homed to the tumor, with tumor regression ongoing in three patients for 14, 22, and 27 months, respectively. No treatment-related adverse effects were observed. This proof-of-principle study shows that tumor-reactive effector cells can...

  9. Vulnerability of cultured canine lung tumor cells to NK cell-mediated cytolysis

    International Nuclear Information System (INIS)

    Haley, P.J.; Kohr, J.M.; Kelly, G.; Muggenburg, B.A.; Guilmette, B.A.

    1988-01-01

    Five cell lines, designated as canine lung epithelial cell (CLEP), derived from radiation induced canine lung tumors and canine thyroid adeno-carcinoma (CTAC) cells were compared for their susceptibility to NK cell-mediated cytolysis using peripheral blood lymphocytes from normal, healthy Beagle dogs as effector cells. Effector cells and chromium 51 radiolabeled target cells were incubated for 16 h at ratios of 12.5:1, 25:1, 50:1, and 100:1. Increasing cytolysis was observed for all cell lines as the effector-to-target-cell ratios increased from 12.5:1 to 100:1. The percent cytotoxicity was significantly less for all lung tumor cell lines as compared to CTAC at the 100:1 ratio. One lung tumor cell line, CLEP-9, had 85% of the lytic vulnerability of the CTAC cell line and significantly greater susceptibility to NK cell-mediated lysis than all of the other lung tumor cell lines. Susceptibility to NK cell cytolysis did not correlate with in vivo malignant behavior of the original tumor. These data suggest that cultured canine lung tumor cells are susceptible to NK cell cytolytic activity in vitro and that at least one of these cell lines (CLEP-9) is a candidate for substitution of the standard canine NK cell target, CTAC, in NK cell assays. The use of lung tumor cells in NK cell assays may provide greater insight into the control of lung tumors by immune mechanisms. (author)

  10. Direct identification of microorganisms from positive blood cultures using the lysis-filtration technique and matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS): a multicentre study.

    Science.gov (United States)

    Farina, Claudio; Arena, Fabio; Casprini, Patrizia; Cichero, Paola; Clementi, Massimo; Cosentino, Marina; Degl'Innocenti, Roberto; Giani, Tommaso; Luzzaro, Francesco; Mattei, Romano; Mauri, Carola; Nardone, Maria; Rossolini, Gian Maria; Serna Ortega, Paula Andrea; Vailati, Francesca

    2015-04-01

    Microbial identification from blood cultures is essential to institute optimal antibiotic therapy and improve survival possibilities. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been successfully applied to identify bacteria and yeasts from positive blood cultures broths. The aim of this multicentre study was to evaluate the reliability of the lysis-filtration technique associated with MALDI-TOF MS to directly identify microorganisms from 765 positive blood cultures collected in six Italian hospitals. Overall, 675/765 (78.1%) blood isolates were correctly identified at the species level, with significant differences between Gram-negative and Gram-positive bacteria (92.6%, and 69.8%, respectively). Some difficulties arise in identifying Streptococcus pneumoniae, Staphylococcus aureus, yeasts and anaerobes. The lysis-filtration protocol is a suitable procedure in terms of performance in identifying microorganisms, but it is quite expensive and technically time-consuming since the time of filtration is not regular for all the samples. The application of the MALDI-TOF MS technique to the direct microbial identification from positive blood cultures is a very promising approach, even if more experience must be gained to minimize errors and costs.

  11. Combined effect of x irradiation and cell-mediated immune reaction

    International Nuclear Information System (INIS)

    Song, C.W.; Guertin, D.P.

    1978-01-01

    The combined effect of radiation and cell-mediated immune reaction on tumor cells was investigated in vitro. Mastocytoma P815-X2 cells of DBA mice either were irradiated first and subjected to immune lysis by immune splenic lymphocytes of C57Bl mice, or the tumor cells were subjected to immune reaction first and then irradiated. Cell survival was quantitated by colony formation in soft agar medium. It was observed that cellular immune damage to tumor cells did not influence the response of tumor cells to subsequent radiation. Irradiation of tumor cells first, followed by subjection of the cells to cellular immune reaction, slightly enhanced the death of the tumor cells. It appears that this enhanced death might have resulted from a relative increase in the ratio of the number of cytotoxic immune cells to the number of target tumor cells in the incubation mixture as a consequence of the decrease in the number of viable tumor cells by radiation

  12. Therapeutic efficacy of interleukin-2 activated killer cells against adriamycin resistant mouse B16-BL6 melanoma.

    Science.gov (United States)

    Gautam, S C; Chikkala, N F; Lewis, I; Grabowski, D R; Finke, J H; Ganapathi, R

    1992-01-01

    Development of multidrug-resistance (MDR) remains a major cause of failure in the treatment of cancer with chemotherapeutic agents. In our efforts to explore alternative treatment regimens for multidrug-resistant tumors we have examined the sensitivity of MDR tumor cell lines to lymphokine activated killer (LAK) cells. Adriamycin (ADM) resistant B16-BL6 melanoma, L1210 and P388 leukemic cell lines were tested for sensitivity to lysis by LAK cells in vitro. While ADM-resistant B16-BL6 and L1210 sublines were found to exhibit at least 2-fold greater susceptibility to lysis by LAK cells, sensitivity of ADM-resistant P388 cell was similar to that of parental cells. Since ADM-resistant B16-BL6 cells were efficiently lysed by LAK cells in vitro, the efficacy of therapy with LAK cells against the ADM-resistant B16-BL6 subline in vivo was evaluated. Compared to mice bearing parental B16-BL6 tumor cells, the adoptive transfer of LAK cells and rIL2 significantly reduced formation of experimental metastases (P less than 0.009) and extended median survival time (P less than 0.001) of mice bearing ADM-resistant B16-BL6 tumor cells. Results suggest that immunotherapy with LAK cells and rIL2 may be a useful modality in the treatment of cancers with the MDR phenotype.

  13. Ultrastructural changes produced in Ehrlich ascites carcinoma cells by ultraviolet-visible radiation in the presence of melanins

    Energy Technology Data Exchange (ETDEWEB)

    Lea, P.J.; Pawlowski, A.; Persad, S.D.; Menon, I.A.; Haberman, H.F.

    1988-01-01

    Irradiation of Ehrlich ascites carcinoma (EAC) cells in the presence of pheomelanin, i.e., red hair melanin (RHM), has been reported to produce extensive cell lysis. Irradiation in the presence of eumelanin, i.e., black hair melanin (BHM), or irradiation in the absence of either type of melanin did not produce this effect. We observed that RHM particles penetrated the cell membrane without apparent structural damage to the cell or the cell membrane. Irradiation of the cells in the absence of melanin did not produce any changes in the ultrastructure of the cells. Incubation of the cells in the dark in the presence of RHM produced only minor structural, mainly cytoplasmic changes. Irradiation of the cells in the presence of RHM produced extensive ultrastructural changes prior to complete cell lysis; these changes were more severe than the effects of incubation of the cells in the dark in the presence of RHM. When the cells incubated in the dark or irradiated in the presence of latex particles or either one of the eumelanins particles, viz. BHM or synthetic dopa melanin, these particles did not penetrate into the cells or produce any ultrastructural changes. These particles were in fact not even ingested by the cells.

  14. Effects of X-irradiation on artificial blood vessel wall degradation by invasive tumor cells

    International Nuclear Information System (INIS)

    Heisel, M.A.; Laug, W.E.; Stowe, S.M.; Jones, P.A.

    1984-01-01

    Artificial vessel wall cultures, constructed by growing arterial endothelial cells on preformed layers of rat smooth muscle cells, were used to evaluate the effects of X-irradiation on tumor cell-induced tissue degradation. Bovine endothelial cells had radiation sensitivities similar to those of rat smooth muscle cells. Preirradiation of smooth muscle cells, before the addition of human fibrosarcoma (HT 1080) cells, did not increase the rate of degradation and destruction by the invasive cells. However, the degradation rate was decreased if the cultures were irradiated after the addition of HT 1080 cells. The presence of bovine endothelial cells markedly inhibited the destructive abilities of fibrosarcoma cells, but preirradiation of artificial vessel walls substantially decreased their capabilities to resist HT 1080-induced lysis. These findings suggest that the abilities of blood vessels to limit extravasation may be compromised by ionizing radiation

  15. Comparative Analysis of Click Chemistry Mediated Activity-Based Protein Profiling in Cell Lysates

    Directory of Open Access Journals (Sweden)

    Yinliang Yang

    2013-10-01

    Full Text Available Activity-based protein profiling uses chemical probes that covalently attach to active enzyme targets. Probes with conventional tags have disadvantages, such as limited cell permeability or steric hindrance around the reactive group. A tandem labeling strategy with click chemistry is now widely used to study enzyme targets in situ and in vivo. Herein, the probes are reacted in live cells, whereas the ensuing detection by click chemistry takes place in cell lysates. We here make a comparison of the efficiency of the activity-based tandem labeling strategy by using Cu(I-catalyzed and strain-promoted click chemistry, different ligands and different lysis conditions.

  16. Single-cell qPCR on dispersed primary pituitary cells -an optimized protocol

    Directory of Open Access Journals (Sweden)

    Haug Trude M

    2010-11-01

    Full Text Available Abstract Background The incidence of false positives is a potential problem in single-cell PCR experiments. This paper describes an optimized protocol for single-cell qPCR measurements in primary pituitary cell cultures following patch-clamp recordings. Two different cell harvesting methods were assessed using both the GH4 prolactin producing cell line from rat, and primary cell culture from fish pituitaries. Results Harvesting whole cells followed by cell lysis and qPCR performed satisfactory on the GH4 cell line. However, harvesting of whole cells from primary pituitary cultures regularly produced false positives, probably due to RNA leakage from cells ruptured during the dispersion of the pituitary cells. To reduce RNA contamination affecting the results, we optimized the conditions by harvesting only the cytosol through a patch pipette, subsequent to electrophysiological experiments. Two important factors proved crucial for reliable harvesting. First, silanizing the patch pipette glass prevented foreign extracellular RNA from attaching to charged residues on the glass surface. Second, substituting the commonly used perforating antibiotic amphotericin B with β-escin allowed efficient cytosol harvest without loosing the giga seal. Importantly, the two harvesting protocols revealed no difference in RNA isolation efficiency. Conclusion Depending on the cell type and preparation, validation of the harvesting technique is extremely important as contaminations may give false positives. Here we present an optimized protocol allowing secure harvesting of RNA from single cells in primary pituitary cell culture following perforated whole cell patch clamp experiments.

  17. Injurious effects of wool and grain dusts on alveolar epithelial cells and macrophages in vitro.

    Science.gov (United States)

    Brown, D M; Donaldson, K

    1991-01-01

    Epidemiological studies of workers in wool textile mills have shown a direct relation between the concentration of wool dust in the air and respiratory symptoms. Injurious effects of wool dust on the bronchial epithelium could be important in causing inflammation and irritation. A pulmonary epithelial cell line in vitro was therefore used to study the toxic effects of wool dust. Cells of the A549 epithelial cell line were labelled with 51Cr and treated with whole wool dusts and extracts of wool, after which injury was assessed. Also, the effects of grain dust, which also causes a form of airway obstruction, were studied. The epithelial injury was assessed by measuring 51Cr release from cells as an indication of lysis, and by monitoring cells which had detached from the substratum. No significant injury to A549 cells was caused by culture with any of the dusts collected from the air but surface "ledge" dust caused significant lysis at some doses. Quartz, used as a toxic control dust, caused significant lysis at the highest concentration of 100 micrograms/well. To determine whether any injurious material was soluble the dusts were incubated in saline and extracts collected. No extracts caused significant injury to epithelial cells. A similar lack of toxicity was found when 51Cr labelled control alveolar macrophages were targets for injury. Significant release of radiolabel was evident when macrophages were exposed to quartz at concentrations of 10 and 20 micrograms/well, there being no significant injury with either wool or grain dusts. These data suggest that neither wool nor grain dust produce direct injury to epithelial cells, and further studies are necessary to explain inflammation leading to respiratory symptoms in wool and grain workers. PMID:2015211

  18. Strain differences in the expression of an H-2K/sup k/ gene product by epidermal and spleen cells

    International Nuclear Information System (INIS)

    Hadley, G.A.; Steinmuller, D.

    1986-01-01

    Cytotoxic T lymphocytes (CTL) directed against Epa-1, a non-H-2 alloantigen expressed by epidermal cells (EC) but no lymphoid cells, lyse EC of different H-2/sup k/, Epa-1 + strains at different levels. For example, the mean percent lysis values for EC of strains CBA, AKR, C58, and RF are 60, 46, 41, and 35 respectively. Since the CTL used to obtain these values recognize Epa-1 only in the context of H-2K/sup k/, the different levels of lysis could reflect differences in either Epa-1 or K/sup k/ antigens. The goal of this investigation was to test the second alternative. For this purpose, the authors obtained hybridoma 16-1-11N that secretes a K/sup k/-specific MoAb. They first demonstrated the capacity of MoAb 16-1-11N to block the lysis of CBA EC by Epa-1-specific CTL. They then utilized it as the probe in a cellar RIA, with 125 I-protein A as the second reagent, to quantitate the expression of K/sup k/ antigens on EC of strains CBA, AKR, C58, and RF. They found that C58 and RF EC bound significantly less of the K/sup k/ MoAb than CBA EC. Although AKR EC also bound less of the MoAb than CBA EC, the difference was not significant. Nonetheless, these data support the hypothesis that the differential susceptibility of the strains to lysis by Epa-1-specific CTL is due to differences in the expression of the H-2 restricting element. The authors also tested spleen cells (SC) of the four strains in the RIA described above and found that SC of RF, but not of C58 or AKR, express reduced levels of K/sup k/ antigens compared to CBA SC

  19. Major histocompatibility complex-unrestricted cytolytic activity of human T cells: analysis of precursor frequency and effector phenotype

    International Nuclear Information System (INIS)

    Patel, S.S.; Thiele, D.L.; Lipsky, P.E.

    1987-01-01

    The frequency and phenotype of human T cells that mediate major histocompatibility complex (MHC)-unrestricted cytolysis were analyzed. T cell clones were generated by culturing adherent cell-depleted peripheral blood mononuclear cells at a density of 0.3 cell/well with phytohemagglutinin, recombinant interleukin 2 (rIL-2), and irradiated autologous peripheral blood mononuclear cells and/or Epstein-Barr virus-transformed lymphoblastoid cell lines. All of the 198 clones generated by this method were T cells (CD2 + , CD3 + , CD4 + or CD2 + , CD3 + , CD8 + ) that possessed potent lytic activity against K562, an erythroleukemia line sensitive to lysis by human natural killer cells, and Cur, a renal carcinoma cell line resistant to human natural killer activity. Cytolysis, measured by 51 Cr release, was MHC-unrestricted, since the clones were able to lyse MHC class I or class II negative targets, as well as MHC class I and class II negative targets. Although the clones produced tissue necrosis factor/lymphotoxin-like molecules, lysis of Cur of K562 was not mediated by a soluble factor secreted by the clones. These data indicate that the capacity for MHC-unrestricted tumoricidal activity and expression of NKH1 and CD11b, but not CD 16, are properties common to all or nearly all human peripheral blood-derived T cell clones regardless of CD4 or CD8 phenotype

  20. Impact of 2-bromopropane on mouse embryonic stem cells and ...

    African Journals Online (AJOL)

    EWOMAZINO

    medium containing various concentrations of 2-BP at 37°C in a CO2 incubator for 24 h. Cells were then washed twice with ice-cold PBS and lysed on ice for 10 min in 400 μl lysis buffer (20 mM Tris-HCl,. pH 7.4, 1 mM EDTA, 1 mM EGTA, 1% Triton X-100, 1 mM benzamidine, 1 mM phenylmethylsulfonyl fluoride, 50 mM NaF, ...

  1. Lysis solution composition and non-linear dose-response to ionizing radiation in the non-denaturing DNA filter elution technique

    International Nuclear Information System (INIS)

    Radford, I.R.

    1990-01-01

    The suggestion by Okayasu and Iliakis (1989) that the non-linear dose-response curve, obtained with the non-denaturing filter elution technique for mammalian cells exposed to low-LET radiation, is the result of a technical artefact, was not confirmed. (author)

  2. Bacterial Cell Wall Precursor Phosphatase Assays Using Thin-layer Chromatography (TLC) and High Pressure Liquid Chromatography (HPLC).

    Science.gov (United States)

    Pazos, Manuel; Otten, Christian; Vollmer, Waldemar

    2018-03-20

    Peptidoglycan encases the bacterial cytoplasmic membrane to protect the cell from lysis due to the turgor. The final steps of peptidoglycan synthesis require a membrane-anchored substrate called lipid II, in which the peptidoglycan subunit is linked to the carrier lipid undecaprenol via a pyrophosphate moiety. Lipid II is the target of glycopeptide antibiotics and several antimicrobial peptides, and is degraded by 'attacking' enzymes involved in bacterial competition to induce lysis. Here we describe two protocols using thin-layer chromatography (TLC) and high pressure liquid chromatography (HPLC), respectively, to assay the digestion of lipid II by phosphatases such as Colicin M or the LXG toxin protein TelC from Streptococcus intermedius . The TLC method can also monitor the digestion of undecaprenyl (pyro)phosphate, whereas the HPLC method allows to separate the di-, mono- or unphosphorylated disaccharide pentapeptide products of lipid II.

  3. Effects of melanin-induced free radicals on the isolated rat peritoneal mast cells

    International Nuclear Information System (INIS)

    Ranadive, N.S.; Shirwadkar, S.; Persad, S.; Menon, I.A.

    1986-01-01

    Pheomelanin from human red hair (RHM) produces considerably more cellular damage in Ehrlich ascites carcinoma cells when subjected to radiations of wavelength 320-700 nm than eumelanin from black hair (BHM). Irradiation of RHM generated large amounts of superoxide while BHM did not produce detectable amounts of superoxide. The present investigations describe the effects of irradiation of mast cells in the presence of various natural and synthetic melanins. Irradiation of mast cells in the presence of RHM and red hair melanoprotein released large amounts of histamine while BHM and synthetic melanins prepared from dopa, cysteinyldopa, or a mixture of dopa and cysteinyldopa did not release histamine. The release of histamine at lower concentrations of RHM was not accompanied by the release of 51 Cr from chromium-loaded cells, suggesting that this release was of noncytotoxic nature. On the other hand, the release of histamine at higher concentrations of RHM was due to cell lysis since both histamine and cytoplasmic marker 51 Cr were released to the same extent. The release evoked by large concentration RHM was not inhibited by superoxide dismutase or catalase. This suggests that the cell lysis under these conditions was not due to H 2 O 2 or O-2. The finding that mast cells release histamine when irradiated in the presence of RHM suggests that the immediate and late-phase reactions seen in sunburn may in part be due to the release of mediators from these cells

  4. Effects of melanin-induced free radicals on the isolated rat peritoneal mast cells

    Energy Technology Data Exchange (ETDEWEB)

    Ranadive, N.S.; Shirwadkar, S.; Persad, S.; Menon, I.A.

    1986-03-01

    Pheomelanin from human red hair (RHM) produces considerably more cellular damage in Ehrlich ascites carcinoma cells when subjected to radiations of wavelength 320-700 nm than eumelanin from black hair (BHM). Irradiation of RHM generated large amounts of superoxide while BHM did not produce detectable amounts of superoxide. The present investigations describe the effects of irradiation of mast cells in the presence of various natural and synthetic melanins. Irradiation of mast cells in the presence of RHM and red hair melanoprotein released large amounts of histamine while BHM and synthetic melanins prepared from dopa, cysteinyldopa, or a mixture of dopa and cysteinyldopa did not release histamine. The release of histamine at lower concentrations of RHM was not accompanied by the release of /sup 51/Cr from chromium-loaded cells, suggesting that this release was of noncytotoxic nature. On the other hand, the release of histamine at higher concentrations of RHM was due to cell lysis since both histamine and cytoplasmic marker /sup 51/Cr were released to the same extent. The release evoked by large concentration RHM was not inhibited by superoxide dismutase or catalase. This suggests that the cell lysis under these conditions was not due to H/sub 2/O/sub 2/ or O-2. The finding that mast cells release histamine when irradiated in the presence of RHM suggests that the immediate and late-phase reactions seen in sunburn may in part be due to the release of mediators from these cells.

  5. Comparison of reverse transcription-quantitative polymerase chain reaction methods and platforms for single cell gene expression analysis.

    Science.gov (United States)

    Fox, Bridget C; Devonshire, Alison S; Baradez, Marc-Olivier; Marshall, Damian; Foy, Carole A

    2012-08-15

    Single cell gene expression analysis can provide insights into development and disease progression by profiling individual cellular responses as opposed to reporting the global average of a population. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) is the "gold standard" for the quantification of gene expression levels; however, the technical performance of kits and platforms aimed at single cell analysis has not been fully defined in terms of sensitivity and assay comparability. We compared three kits using purification columns (PicoPure) or direct lysis (CellsDirect and Cells-to-CT) combined with a one- or two-step RT-qPCR approach using dilutions of cells and RNA standards to the single cell level. Single cell-level messenger RNA (mRNA) analysis was possible using all three methods, although the precision, linearity, and effect of lysis buffer and cell background differed depending on the approach used. The impact of using a microfluidic qPCR platform versus a standard instrument was investigated for potential variability introduced by preamplification of template or scaling down of the qPCR to nanoliter volumes using laser-dissected single cell samples. The two approaches were found to be comparable. These studies show that accurate gene expression analysis is achievable at the single cell level and highlight the importance of well-validated experimental procedures for low-level mRNA analysis. Copyright © 2012 Elsevier Inc. All rights reserved.

  6. Nonthermal-plasma-mediated animal cell death

    Science.gov (United States)

    Kim, Wanil; Woo, Kyung-Chul; Kim, Gyoo-Cheon; Kim, Kyong-Tai

    2011-01-01

    Animal cell death comprising necrosis and apoptosis occurred in a well-regulated manner upon specific stimuli. The physiological meanings and detailed molecular mechanisms of cell death have been continuously investigated over several decades. Necrotic cell death has typical morphological changes, such as cell swelling and cell lysis followed by DNA degradation, whereas apoptosis shows blebbing formation and regular DNA fragmentation. Cell death is usually adopted to terminate cancer cells in vivo. The current strategies against tumour are based on the induction of cell death by adopting various methods, including radiotherapy and chemotherapeutics. Among these, radiotherapy is the most frequently used treatment method, but it still has obvious limitations. Recent studies have suggested that the use of nonthermal air plasma can be a prominent method for inducing cancer cell death. Plasma-irradiated cells showed the loss of genomic integrity, mitochondrial dysfunction, plasma membrane damage, etc. Tumour elimination with plasma irradiation is an emerging concept in cancer therapy and can be accelerated by targeting certain tumour-specific proteins with gold nanoparticles. Here, some recent developments are described so that the mechanisms related to plasma-mediated cell death and its perspectives in cancer treatment can be understood.

  7. Nonthermal-plasma-mediated animal cell death

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Wanil; Woo, Kyung-Chul; Kim, Kyong-Tai [Department of Life Science, Division of Molecular and Life Science, Pohang University of Science and Technology, San 31, Hyoja Dong, Pohang 790-784 (Korea, Republic of); Kim, Gyoo-Cheon, E-mail: ktk@postech.ac.kr [Department of Oral Anatomy and Cell Biology, School of Dentistry, Pusan National University, Yangsan 626-810 (Korea, Republic of)

    2011-01-12

    Animal cell death comprising necrosis and apoptosis occurred in a well-regulated manner upon specific stimuli. The physiological meanings and detailed molecular mechanisms of cell death have been continuously investigated over several decades. Necrotic cell death has typical morphological changes, such as cell swelling and cell lysis followed by DNA degradation, whereas apoptosis shows blebbing formation and regular DNA fragmentation. Cell death is usually adopted to terminate cancer cells in vivo. The current strategies against tumour are based on the induction of cell death by adopting various methods, including radiotherapy and chemotherapeutics. Among these, radiotherapy is the most frequently used treatment method, but it still has obvious limitations. Recent studies have suggested that the use of nonthermal air plasma can be a prominent method for inducing cancer cell death. Plasma-irradiated cells showed the loss of genomic integrity, mitochondrial dysfunction, plasma membrane damage, etc. Tumour elimination with plasma irradiation is an emerging concept in cancer therapy and can be accelerated by targeting certain tumour-specific proteins with gold nanoparticles. Here, some recent developments are described so that the mechanisms related to plasma-mediated cell death and its perspectives in cancer treatment can be understood. (topical review)

  8. Nonthermal-plasma-mediated animal cell death

    International Nuclear Information System (INIS)

    Kim, Wanil; Woo, Kyung-Chul; Kim, Kyong-Tai; Kim, Gyoo-Cheon

    2011-01-01

    Animal cell death comprising necrosis and apoptosis occurred in a well-regulated manner upon specific stimuli. The physiological meanings and detailed molecular mechanisms of cell death have been continuously investigated over several decades. Necrotic cell death has typical morphological changes, such as cell swelling and cell lysis followed by DNA degradation, whereas apoptosis shows blebbing formation and regular DNA fragmentation. Cell death is usually adopted to terminate cancer cells in vivo. The current strategies against tumour are based on the induction of cell death by adopting various methods, including radiotherapy and chemotherapeutics. Among these, radiotherapy is the most frequently used treatment method, but it still has obvious limitations. Recent studies have suggested that the use of nonthermal air plasma can be a prominent method for inducing cancer cell death. Plasma-irradiated cells showed the loss of genomic integrity, mitochondrial dysfunction, plasma membrane damage, etc. Tumour elimination with plasma irradiation is an emerging concept in cancer therapy and can be accelerated by targeting certain tumour-specific proteins with gold nanoparticles. Here, some recent developments are described so that the mechanisms related to plasma-mediated cell death and its perspectives in cancer treatment can be understood. (topical review)

  9. Whole-cell hybridization of Methanosarcina cells with two new oligonucleotide probes

    DEFF Research Database (Denmark)

    Sørensen, A.H.; Torsvik, V.L.; Torsvik, T.

    1997-01-01

    Two new oligonucleotide probes targeting the 16S rRNA of the methanogenic genus Methanosarcina were developed. The probes have the following sequences (Escherichia coli numbering): probe SARCI551, 5'-GAC CCAATAATCACGATCAC-3', and probe SARCI645, 5'-TCCCGGTTCCAAGTCTGGC-3'. In situ hybridization...... with the fluorescently labelled probes required several modifications of standard procedures. Cells of Methanosarcina mazeii S-6 were found to lyse during the hybridization step if fixed in 3% formaldehyde and stored in 50% ethanol. Lysis was, however, not observed with cells fixed and stored in 1.6% formaldehyde-0.......85% NaCl. Extensive autofluorescence of the cells was found upon hybridization in the presence of 5 mM EDTA, but successful hybridization could be obtained without addition of this compound. The mounting agent Citifluor AF1, often used in conjugation with the fluorochrome fluorescein, was found to wash...

  10. Fundamental studies on ADCC (antibody-dependent cell-mediated cytotoxicity) of human peripheral blood leukocytes using sheep red blood cells as target cells, and the effect of erythrophagocytosis

    International Nuclear Information System (INIS)

    Ichikawa, Yukinobu; Takaya, Masatoshi; Arimori, Shigeru

    1979-01-01

    We investigated antibody-dependent cell-mediated cytotoxicity (ADCC) of human peripheral blood leukocytes by using 51 Cr-labelled sheep red blood cells (SRBC) as target cells and anti-SRBC rabbit antibody. Lysis of SRBC was mediated by either human peripheral lymphoid cells or phagocytes (Monocytes and granulocytes). SRBC were useful as target cells in ADCC assay against human lymphoid cells, since decreased cytotoxic activity of phagocyte-contaminated crude lymphocyte fraction was recovered by elimination of contaminating phagocytes. The monocytes inhibited ADCC of lymphoid cells through phagocytosis of SRBC. This assay system may be useful for estimating not only Fc receptor-mediated cytotoxicity but also Fc receptor-mediated phagocytic activity of human peripheral blood leukocytes. (author)

  11. Analysis of ribosomal RNA stability in dead cells of wine yeast by quantitative PCR.

    Science.gov (United States)

    Sunyer-Figueres, Merce; Wang, Chunxiao; Mas, Albert

    2018-04-02

    During wine production, some yeasts enter a Viable But Not Culturable (VBNC) state, which may influence the quality and stability of the final wine through remnant metabolic activity or by resuscitation. Culture-independent techniques are used for obtaining an accurate estimation of the number of live cells, and quantitative PCR could be the most accurate technique. As a marker of cell viability, rRNA was evaluated by analyzing its stability in dead cells. The species-specific stability of rRNA was tested in Saccharomyces cerevisiae, as well as in three species of non-Saccharomyces yeast (Hanseniaspora uvarum, Torulaspora delbrueckii and Starmerella bacillaris). High temperature and antimicrobial dimethyl dicarbonate (DMDC) treatments were efficient in lysing the yeast cells. rRNA gene and rRNA (as cDNA) were analyzed over 48 h after cell lysis by quantitative PCR. The results confirmed the stability of rRNA for 48 h after the cell lysis treatments. To sum up, rRNA may not be a good marker of cell viability in the wine yeasts that were tested. Copyright © 2018 Elsevier B.V. All rights reserved.

  12. Induction of rapid and selective cell necrosis in Drosophila using Bacillus thuringiensis Cry toxin and its silkworm receptor.

    Science.gov (United States)

    Obata, Fumiaki; Tanaka, Shiho; Kashio, Soshiro; Tsujimura, Hidenobu; Sato, Ryoichi; Miura, Masayuki

    2015-07-08

    Genetic ablation of target cells is a powerful tool to study the origins and functions of cells, tissue regeneration, or pathophysiology in a human disease model in vivo. Several methods for selective cell ablation by inducing apoptosis have been established, using exogenous toxins or endogenous proapoptotic genes. However, their application is limited to cells with intact apoptotic machinery. Herein, we established a method for inducing rapid and selective cell necrosis by the pore-forming bacterial toxin Cry1Aa, which is specifically active in cells expressing the Cry1Aa receptor (CryR) derived from the silkworm Bombyx mori. We demonstrated that overexpressing CryR in Drosophila melanogaster tissues induced rapid cell death of CryR-expressing cells only, in the presence of Cry1Aa toxin. Cry/CryR system was effective against both proliferating cells in imaginal discs and polyploid postmitotic cells in the fat body. Live imaging analysis of cell ablation revealed swelling and subsequent osmotic lysis of CryR-positive cells after 30 min of incubation with Cry1Aa toxin. Osmotic cell lysis was still triggered when apoptosis, JNK activation, or autophagy was inhibited, suggesting that Cry1Aa-induced necrotic cell death occurred independently of these cellular signaling pathways. Injection of Cry1Aa into the body cavity resulted in specific ablation of CryR-expressing cells, indicating the usefulness of this method for in vivo cell ablation. With Cry toxins from Bacillus thuringiensis, we developed a novel method for genetic induction of cell necrosis. Our system provides a "proteinous drill" for killing target cells through physical injury of the cell membrane, which can potentially be used to ablate any cell type in any organisms, even those that are resistant to apoptosis or JNK-dependent programmed cell death.

  13. NKp46 defines ovine cells that have characteristics corresponding to NK cells

    Directory of Open Access Journals (Sweden)

    Connelley Timothy

    2011-02-01

    Full Text Available Abstract Natural killer (NK cells are well recognized as playing a key role in innate immune defence through cytokine production and cytotoxic activity; additionally recent studies have identified several novel NK cell functions. The ability to study NK cells in the sheep has been restricted due to a lack of specific reagents. We report the generation of a monoclonal antibody specific for ovine NKp46, a receptor which in a number of mammals is expressed exclusively in NK cells. Ovine NKp46+ cells represent a population that is distinct from CD4+ and γδ+ T-cells, B-cells and cells of the monocytic lineage. The NKp46+ cells are heterogenous with respect to expression of CD2 and CD8 and most, but not all, express CD16 - characteristics consistent with NK cell populations in other species. We demonstrate that in addition to populations in peripheral blood and secondary lymphoid organs, ovine NKp46+ populations are also situated at the mucosal surfaces of the lung, gastro-intestinal tract and non-gravid uterus. Furthermore, we show that purified ovine NKp46+ populations cultured in IL-2 and IL-15 have cytotoxic activity that could be enhanced by ligation of NKp46 in re-directed lysis assays. Therefore we conclude that ovine NKp46+ cells represent a population that by phenotype, tissue distribution and function correspond to NK cells and that NKp46 is an activating receptor in sheep as in other species.

  14. Síndrome de lisis tumoral en un paciente con cáncer de riñón tratado con sunitinib Tumor lysis syndrome in a patient with a renal carcinoma treated with sunitinib

    Directory of Open Access Journals (Sweden)

    Ezequiel Rodríguez-Reimúndes

    2011-04-01

    Full Text Available El síndrome de lisis tumoral (SLT es un trastorno metabólico que ocurre como consecuencia de una destrucción celular masiva. Se caracteriza por la presencia de hiperuricemia, hiperfosfatemia, hipocalcemia e hiperkalemia, y predispone al desarrollo de insuficiencia renal aguda. En la mayoría de los casos el SLT ocurre luego de instaurarse un tratamiento antitumoral y es más frecuente en tumores de alto grado de malignidad y alta sensibilidad a la quimioterapia. Presentamos el caso de un paciente con diagnóstico de cáncer de riñón recidivado que presenta un SLT e insuficiencia renal aguda luego de iniciar tratamiento con sunitinib.The tumor mor lysis syndrome (TLS is a metabolic disorder resulting from a massive tumor breakdown. It is characterized by hyperuricemia, hyperphosphatemia, hypocalcemia and hyperkalemia and predisposes to acute renal failure. TLS usually occurs after the initiation of cytotoxic therapy and is more frequent in the case of neoplasias with a high proliferative rate or that are highly chemo-sensitive. We report the case of a man with a recurrent kidney cancer who presented with a TLS and acute renal failure after initiation of sunitinib.

  15. Staphylococcus aureus α-toxin-dependent induction of host cell death by membrane-derived vesicles.

    Directory of Open Access Journals (Sweden)

    Bernard Thay

    Full Text Available Staphylococcus aureus causes a wide spectrum of infections in humans, ranging from superficial cutaneous infections, infections in the circum-oral region, to life-threatening bacteremia. It was recently demonstrated that Gram-positive organisms such as S. aureus liberate membrane-derived vesicles (MVs, which analogously to outer membrane vesicles (OMVs of Gram-negative bacteria can play a role in delivering virulence factors to host cells. In the present study we have shown that cholesterol-dependent fusion of S. aureus MVs with the plasma membrane represents a route for delivery of a key virulence factor, α-toxin (α-hemolysin; Hla to human cells. Most S. aureus strains produce this 33-kDa pore-forming protein, which can lyse a wide range of human cells, and induce apoptosis in T-lymphocytes. Our results revealed a tight association of biologically active α-toxin with membrane-derived vesicles isolated from S. aureus strain 8325-4. Concomitantly, α-toxin contributed to HeLa cell cytotoxicity of MVs, and was the main vesicle-associated protein responsible for erythrocyte lysis. In contrast, MVs obtained from an isogenic hla mutant were significantly attenuated with regards to both causing lysis of erythrocytes and death of HeLa cells. This is to our knowledge the first recognition of an S. aureus MV-associated factor contributing to host cell cytotoxicity.

  16. Local lysis with Alteplase for the treatment of acute embolic leg ischemia following the use of the Duett {sup trademark} closure device: preliminary results; Lokale Alteplase-Lyse zur Therapie der akuten embolischen Beinischaemie nach Einsatz des Duett {sup trademark} -Verschluss-Systems: vorlaeufige Ergebnisse

    Energy Technology Data Exchange (ETDEWEB)

    Schuermann, K.; Buecker, A.; Wingen, M.; Tacke, J.; Wein, B.; Guenther, R.W. [Klinik fuer Radiologische Diagnostik des Universitaetsklinikums der RWTH Aachen (Germany); Janssens, U. [Medizinische Klinik I (Kardiologie) des Universitaetsklinikums der RWTH Aachen (Germany)

    2004-04-01

    Purpose: To analyze retrospectively the result of the alteplase lysis therapy of embolic complications following the use of the Duett closure device. Methods and Materials: For 3.5 years, the Duett closure device was used in 1,398 angiographies to close the femoral puncture site. The Duett device consists of a balloon and a liquid procoagulant containing collagen and thrombin, which is injected into the puncture tract under endovascular balloon protection of the arterial puncture site. In 9 patients (0.64%), the procoagulant was incidentally injected into the femoral artery causing acute leg ischemia. Eight patients received local lysis therapy with alteplase via a contralateral femoral access. One patient underwent surgery. On average, 21 mg alteplase (4-35 mg) were administered within 14 h (4-21 h). The course of the lysis was followed angiographyically and clinically. All patients were inteerviewed by telephone 23 months (4-35 months) later.Results: In 3 patients, lysis was complete. In 5 patients, only little thrombotic material remained. In all patients, symptoms of ischemia resolved completely within the first hours after initiation of lysis. In 5 cases, bleeding occurred at the puncture site closed with the Duett device during lysis, including development of a false aneurysm in 2 cases. Complications led to premature termination (n=2) or interruption of the lysis (n=3). All complications were treated conservatively. Clinically, long-term sequelae were paresthesia and hypoesthesia in the lower leg and foot in 2 patients treated with lysis, and in the patient who underwent surgery. (orig.) [German] Ziel: Das Ergebnis der Alteplase-Lysetherapie von Embolien nach Einsatz des Duett-Verschluss-Systems wurde retrospektiv untersucht. Methoden: Innerhalb von 3,5 Jahren wurde nach 1398 Angiographien das Duett-System zum Verschluss der femoralen Punktionsstelle eingesetzt. Das System besteht aus einem Ballon und einem fluessigen Prokoagulans (Kollagen, Thrombin), das

  17. The inhibition of repair in UV irradiated human cells

    International Nuclear Information System (INIS)

    Collins, A.R.S.; Schor, S.L.; Johnson, R.T.

    1977-01-01

    Three different assay procedures are used to determine the effects of hydroxyurea on excision repair in UV-irradiated HeLa cells. At the cytological level, incubation of UV-irradiated metaphase cells with hydroxyurea caused chromosome decondensation. Using a modified alkaline sucrose gradient sedimentation technique involving minimal lysis before centrifugation, a marked retardation was found in the sedimentation of DNA from UV-irradiated cells incubated for a short period with hydroxyurea. The effect of hydroxyurea on the incorporation of [ 3 H]thymidine by UV-irradiated G1 cells was found to depend on the concentration of thymidine present in the medium. The results point to an inhibition of repair DNA synthesis by hydroxyurea (or deoxyadenosine), at the level of the supply of DNA precursors, i.e. in the same way that these agents inhibit semiconservative DNA synthesis. In the presence of these inhibitors, single-strand gaps accumulate in the DNA

  18. Uptake of carnitine by red blood cells

    International Nuclear Information System (INIS)

    Campa, M.; Borum, P.

    1986-01-01

    A significant amount of blood carnitine (70% of cord blood and 40% of blood from healthy adults) is partitioned into the red blood cell compartment of whole blood. Data indicate that the plasma compartment and the red blood cell compartment of whole blood represent different metabolic pools of carnitine. There are no data to indicate that red blood cells synthesize carnitine, but our understanding of the uptake of carnitine by red blood cells is negligible. Red blood cells were obtained from healthy adults, washed twice with normal saline, and used for uptake experiments. When the cells were incubated at 37 0 C in the presence of 14 C-carnitine, radioactivity was found both in the soluble cytosolic and membrane fractions of the cells following lysis. The uptake was dependent upon the time of incubation, temperature of incubation, and carnitine concentration in the incubation medium. Washed red blood cell membranes incubated with 14 C-carnitine showed specific binding of radioactivity. These data are consistent with the hypothesis that red blood cells have an uptake mechanism for L-carnitine

  19. Direct digestion of proteins in living cells into peptides for proteomic analysis.

    Science.gov (United States)

    Chen, Qi; Yan, Guoquan; Gao, Mingxia; Zhang, Xiangmin

    2015-01-01

    To analyze the proteome of an extremely low number of cells or even a single cell, we established a new method of digesting whole cells into mass-spectrometry-identifiable peptides in a single step within 2 h. Our sampling method greatly simplified the processes of cell lysis, protein extraction, protein purification, and overnight digestion, without compromising efficiency. We used our method to digest hundred-scale cells. As far as we know, there is no report of proteome analysis starting directly with as few as 100 cells. We identified an average of 109 proteins from 100 cells, and with three replicates, the number of proteins rose to 204. Good reproducibility was achieved, showing stability and reliability of the method. Gene Ontology analysis revealed that proteins in different cellular compartments were well represented.

  20. Counter-flow elutriation of clinical peripheral blood mononuclear cell concentrates for the production of dendritic and T cell therapies.

    Science.gov (United States)

    Stroncek, David F; Fellowes, Vicki; Pham, Chauha; Khuu, Hanh; Fowler, Daniel H; Wood, Lauren V; Sabatino, Marianna

    2014-09-17

    Peripheral blood mononuclear cells (PBMC) concentrates collected by apheresis are frequently used as starting material for cellular therapies, but the cell of interest must often be isolated prior to initiating manufacturing. The results of enriching 59 clinical PBMC concentrates for monocytes or lymphocytes from patients with solid tumors or multiple myeloma using a commercial closed system semi-automated counter-flow elutriation instrument (Elutra, Terumo BCT) were evaluated for quality and consistency. Elutriated monocytes (n = 35) were used to manufacture autologous dendritic cells and elutriated lymphocytes (n = 24) were used manufacture autologous T cell therapies. Elutriated monocytes with >10% neutrophils were subjected to density gradient sedimentation to reduce neutrophil contamination and elutriated lymphocytes to RBC lysis. Elutriation separated the PBMC concentrates into 5 fractions. Almost all of the lymphocytes, platelets and red cells were found in fractions 1 and 2; in contrast, most of the monocytes, 88.6 ± 43.0%, and neutrophils, 74.8 ± 64.3%, were in fraction 5. In addition, elutriation of 6 PBMCs resulted in relatively large quantities of monocytes in fractions 1 or 2. These 6 PBMCs contained greater quantities of monocytes than the other 53 PBMCs. Among fraction 5 isolates 38 of 59 contained >10% neutrophils. High neutrophil content of fraction 5 was associated with greater quantities of neutrophils in the PBMC concentrate. Following density gradient separation the neutrophil counts fell to 3.6 ± 3.4% (all products contained <10% neutrophils). Following red cell lysis of the elutriated lymphocyte fraction the lymphocyte recovery was 86.7 ± 24.0% and 34.3 ± 37.4% of red blood cells remained. Elutriation was consistent and effective for isolating monocytes and lymphocytes from PBMC concentrates for manufacturing clinical cell therapies, but further processing is often required.

  1. Effects of 1 MHz ultrasound on Chinese hamster V-79 cells: cavitational mechanisms and effects on proliferation

    International Nuclear Information System (INIS)

    Ciaravino, V.

    1982-01-01

    An assessment of acoustic cavitation as a primary physical mechanism in producing chemical and biological effects has been made. Chemical effects have been demonstrated through experimental protocols involving the release of iodine from sodium iodide. Biological effects have been shown by procedures assessing cell lysis and growth of in vitro Chinese hamsters V-79 cells. An important conclusion reached through these assessments is that the threshold level at which acoustic cavitation can exert an effect is dependent on the sensitivity of the experimental system being exposed. The proliferation of mitotically synchronous in vitro Chinese hamster V-79 cells exposed to 1 MHz ultrasound was investigated. Cell growth was assessed in the first three hours after sonication (3 W/cm 2 for 1 min) and was found to decrease to approx. 60 percent of control values. At an intensity of 3 W/cm 2 and exposure durations of 0.1, 1, 2, 5, and 10 min., mitotic cells underwent respectively increasing amounts of lysis. The remaining intact cells were observed for growth rate as indicated by the timed formation of colonies from single cells. The results indicated an immediate decrease in colony size (p 0.05)

  2. Stromal Cells Act as Guardians for Endothelial Progenitors by Reducing Their Immunogenicity After Co-Transplantation.

    Science.gov (United States)

    Souidi, Naima; Stolk, Meaghan; Rudeck, Juliane; Strunk, Dirk; Schallmoser, Katharina; Volk, Hans-Dieter; Seifert, Martina

    2017-05-01

    Regeneration of injured tissues requires effective therapeutic strategies supporting vasculogenesis. The lack of instantly available autologous cell sources and immunogenicity of allogeneic endothelial (progenitor) cells limits clinical progress. Based on the immunosuppressive potency of mesenchymal stem/progenitor cells (MSCs), we investigated whether crosstalk between endothelial colony-forming progenitor cells (ECFCs) and MSCs during vasculogenesis could lower allogeneic T cell responses against ECFCs allowing long-term engraftment in vivo. Immunodeficient mice received subcutaneous grafts containing human ECFCs alone, or pairs of human ECFCs/MSCs from the same umbilical cord (UC) to study vasculogenesis in the presence of human leukocyte antigen (HLA)-mismatched human peripheral blood mononuclear cells (PBMCs). In vitro, cell surface marker changes due to interferon gamma (IFNγ) stimulation during ECFC/MSC coculture were determined and further effects on allostimulated T cell proliferation and cytotoxic lysis were measured. IFNγ-induced HLA-DR expression on ECFCs and MSCs, but both cell types had significantly less HLA-DR in cocultures. ECFC-induced T cell proliferation was abolished after MSC coculture as a result of HLA-DR downregulation and indolamin-2,3-dioxygenase activation. Additionally, allospecific CD8 + T cell-mediated lysis of ECFCs was reduced in cocultures. ECFC/MSC coapplication in immunodeficient mice not only promoted the generation of improved blood vessel architecture after 6 weeks, but also reduced intragraft immune cell infiltration and endothelial HLA-DR expression following PBMC reconstitution. Crosstalk between UC-derived ECFCs and MSCs after combined transplantation can lower the risk of ECFC rejection, thus enabling their coapplication for therapeutic vasculogenesis. Stem Cells 2017;35:1233-1245. © 2017 AlphaMed Press.

  3. Bleeding and infection with external ventricular drainage: a systematic review in comparison with adjudicated adverse events in the ongoing Clot Lysis Evaluating Accelerated Resolution of Intraventricular Hemorrhage Phase III (CLEAR-III IHV) trial.

    Science.gov (United States)

    Dey, Mahua; Stadnik, Agnieszka; Riad, Fady; Zhang, Lingjiao; McBee, Nichol; Kase, Carlos; Carhuapoma, J Ricardo; Ram, Malathi; Lane, Karen; Ostapkovich, Noeleen; Aldrich, Francois; Aldrich, Charlene; Jallo, Jack; Butcher, Ken; Snider, Ryan; Hanley, Daniel; Ziai, Wendy; Awad, Issam A

    2015-03-01

    Retrospective series report varied rates of bleeding and infection with external ventricular drainage (EVD). There have been no prospective studies of these risks with systematic surveillance, threshold definitions, or independent adjudication. To analyze the rate of complications in the ongoing Clot Lysis: Evaluating Accelerated Resolution of Intraventricular Hemorrhage Phase III (CLEAR III) trial, providing a comparison with a systematic review of complications of EVD in the literature. Patients were prospectively enrolled in the CLEAR III trial after placement of an EVD for obstructive intraventricular hemorrhage and randomized to receive recombinant tissue-type plasminogen activator or placebo. We counted any detected new hemorrhage (catheter tract hemorrhage or any other distant hemorrhage) on computed tomography scan within 30 days from the randomization. Meta-analysis of published series of EVD placement was compiled with STATA software. Growing or unstable hemorrhage was reported as a cause of exclusion from the trial in 74 of 5707 cases (1.3%) screened for CLEAR III. The first 250 patients enrolled have completed adjudication of adverse events. Forty-two subjects (16.8%) experienced ≥1 new bleeds or expansions, and 6 of 250 subjects (2.4%) suffered symptomatic hemorrhages. Eleven cases (4.4%) had culture-proven bacterial meningitis or ventriculitis. Risks of bleeding and infection in the ongoing CLEAR III trial are comparable to those previously reported in EVD case series. In the present study, rates of new bleeds and bacterial meningitis/ventriculitis are very low despite multiple daily injections, blood in the ventricles, the use of thrombolysis in half the cases, and generalization to >60 trial sites.

  4. A bispecific nanobody approach to leverage the potent and widely applicable tumor cytolytic capacity of Vγ9Vδ2-T cells.

    Science.gov (United States)

    de Bruin, Renée C G; Veluchamy, John P; Lougheed, Sinéad M; Schneiders, Famke L; Lopez-Lastra, Silvia; Lameris, Roeland; Stam, Anita G; Sebestyen, Zsolt; Kuball, Jürgen; Molthoff, Carla F M; Hooijberg, Erik; Roovers, Rob C; Santo, James P Di; van Bergen En Henegouwen, Paul M P; Verheul, Henk M W; de Gruijl, Tanja D; van der Vliet, Hans J

    2017-01-01

    Though Vγ9Vδ2-T cells constitute only a small fraction of the total T cell population in human peripheral blood, they play a vital role in tumor defense and are therefore of major interest to explore for cancer immunotherapy. Vγ9Vδ2-T cell-based cancer immunotherapeutic approaches developed so far have been generally well tolerated and were able to induce significant clinical responses. However, overall results were inconsistent, possibly due to the fact that these strategies induced systemic activation of Vγ9Vδ2-T cells without preferential accumulation and targeted activation in the tumor. Here we show that a novel bispecific nanobody-based construct targeting both Vγ9Vδ2-T cells and EGFR induced potent Vγ9Vδ2-T cell activation and subsequent tumor cell lysis both in vitro and in an in vivo mouse xenograft model. Tumor cell lysis was independent of KRAS and BRAF tumor mutation status and common Vγ9Vδ2-T cell receptor sequence variations. In combination with the conserved monomorphic nature of the Vγ9Vδ2-TCR and the facile replacement of the tumor-specific nanobody, this immunotherapeutic approach can be applied to a large group of cancer patients.

  5. Preparation of antisera specific for human B cells by immunization of rabbits with immune complexes

    International Nuclear Information System (INIS)

    Welsh, K.I.; Turner, M.J.

    1976-01-01

    Three rabbit antisera are described which are specific without absorption (titer 1:100) for separated human B cells, as measured by complement and non-complement fixing assays. The method of production of these sera involved injections of rabbits with precipitin lines formed between 10μ1 of three separate detergent solubilized membrane preparations and 4μ1 aliquots of rabbit antisera to human B cells. In addition to being B cell specific, the three sera block the MLC reaction, inhibit aggregated IgG binding to B cells, and show differential degrees of B cell lysis when tested on a panel of separated B and T cells. These and other properties suggest that the target specificities of the antibodies are the human equivalent of the murine Ia antigens. (author)

  6. DNA fragmentation: manifestation of target cell destruction mediated by cytotoxic T-cell lines, lymphotoxin-secreting helper T-cell clones, and cell-free lymphotoxin-containing supernatant

    International Nuclear Information System (INIS)

    Schmid, D.S.; Tite, J.P.; Ruddle, N.H.

    1986-01-01

    A Lyt-2 + , trinitrophenyl-specific, lymphotoxin-secreting, cytotoxic T-cell line, PCl 55, mediates the digestion of target cell DNA into discretely sized fragments. This phenomenon manifests itself within 30 min after effector cell encounter as measured by the release of 3 H counts from target cells prelabeled with [ 3 H]deoxythymidine and occurs even at very low effector to target cell ratios (0.25:1). A Lyt-1 + , ovalbumin-specific, lymphotoxin-secreting T-helper cell clone, 5.9.24, is also able to mediate fragmentation of target cell DNA over a time course essentially indistinguishable from the cytotoxic T lymphocyte-mediated hit. Cell-free lymphotoxin-containing supernatants also cause release of DNA from targets, although they require a longer time course, on the order of 24 hr. In contrast, lysis of cells by antibody plus complement or Triton X-100 does not result in DNA release even after extended periods of incubation (24 hr). All three treatments that result in the release of DNA from cells cause fragmentation of that DNA into discretely sized pieces that are multiples of 200 base pairs. The results thus suggest that cytotoxic T cells, lymphotoxin-secreting helper clones with cytolytic activity, and lymphotoxin all effect target cell destruction by means of a similar mechanism and that observed differences in time course and the absence of target cell specificity in killing mediated by lymphotoxin may simply reflect differences in the mode of toxin delivery

  7. Mesenchymal Stem Cells after Polytrauma: Actor and Target

    Directory of Open Access Journals (Sweden)

    Markus Huber-Lang

    2016-01-01

    Full Text Available Mesenchymal stem cells (MSCs are multipotent cells that are considered indispensable in regeneration processes after tissue trauma. MSCs are recruited to damaged areas via several chemoattractant pathways where they function as “actors” in the healing process by the secretion of manifold pro- and anti-inflammatory, antimicrobial, pro- and anticoagulatory, and trophic/angiogenic factors, but also by proliferation and differentiation into the required cells. On the other hand, MSCs represent “targets” during the pathophysiological conditions after severe trauma, when excessively generated inflammatory mediators, complement activation factors, and damage- and pathogen-associated molecular patterns challenge MSCs and alter their functionality. This in turn leads to complement opsonization, lysis, clearance by macrophages, and reduced migratory and regenerative abilities which culminate in impaired tissue repair. We summarize relevant cellular and signaling mechanisms and provide an up-to-date overview about promising future therapeutic MSC strategies in the context of severe tissue trauma.

  8. Cytotoxic T lymphocyte-mediated cytolysis: an example of programmed cell death in the immune system

    International Nuclear Information System (INIS)

    Duke, R.C.

    1985-01-01

    Target cells are programmed to die following interaction with cytotoxic T lymphocytes (CTLs). Within minutes of exposure to CTL the target cell's nuclear DNA is fragmented. Target cell lysis, as measured by 51 Cr release, occurs about 60 minutes after induction of DNA fragmentation. DNA fragmentation results from the action of an endonuclease which cleaves DNA in the linker region between nucleosomes. The origin of this nuclease, whether transferred to the target by the CTL or endogenous to the target cell, has not been resolved. DNA fragmentation occurs only when appropriately sensitized CTL are used and is not merely the result of cell death because killing of target cells by extreme deviation from homeostasis, by interruption of energy production, or by lysis with antibody and complement does not induce DNA cleavage. When Triton X-100 is added to target cells which have interacted with CTL, the DNA fragments do not remain in association with the nucleus. This observation suggests that breakdown of overall nuclear structure is induced concomitantly with DNA fragmentation. Morphologically, disruption of nuclear structure and DNA fragmentation are observed as widespread chromatin condensation (apoptosis). Apoptosis is observed in metabolically active target cells and is not a consequence of cell death. A cell whose DNA is extensively fragmented is condemmed to die. Induction of oligonucleosome-sized DNA is also an early event in glucocorticoid-induced thymocyte death and death of T cells upon removal of growth factor. Several similarities exist between these systems and CTL-mediated cytolysis suggesting a final common biochemical pathway for all three types of cell death

  9. Schrödinger’s Cheshire Cat: Are Haploid Emiliania huxleyi Cells Resistant to Viral Infection or Not?

    Directory of Open Access Journals (Sweden)

    Gideon J. Mordecai

    2017-03-01

    Full Text Available Emiliania huxleyi is the main calcite producer on Earth and is routinely infected by a virus (EhV; a double stranded DNA (dsDNA virus belonging to the family Phycodnaviridae. E. huxleyi exhibits a haplodiploid life cycle; the calcified diploid stage is non-motile and forms extensive blooms. The haploid phase is a non-calcified biflagellated cell bearing organic scales. Haploid cells are thought to resist infection, through a process deemed the “Cheshire Cat” escape strategy; however, a recent study detected the presence of viral lipids in the same haploid strain. Here we report on the application of an E. huxleyi CCMP1516 EhV-86 combined tiling array (TA that further confirms an EhV infection in the RCC1217 haploid strain, which grew without any signs of cell lysis. Reverse transcription polymerase chain reaction (RT-PCR and PCR verified the presence of viral RNA in the haploid cells, yet indicated an absence of viral DNA, respectively. These infected cells are an alternative stage of the virus life cycle deemed the haplococcolithovirocell. In this instance, the host is both resistant to and infected by EhV, i.e., the viral transcriptome is present in haploid cells whilst there is no evidence of viral lysis. This superimposed state is reminiscent of Schrödinger’s cat; of being simultaneously both dead and alive.

  10. Schrödinger's Cheshire Cat: Are Haploid Emiliania huxleyi Cells Resistant to Viral Infection or Not?

    Science.gov (United States)

    Mordecai, Gideon J; Verret, Frederic; Highfield, Andrea; Schroeder, Declan C

    2017-03-18

    Emiliania huxleyi is the main calcite producer on Earth and is routinely infected by a virus (EhV); a double stranded DNA (dsDNA) virus belonging to the family Phycodnaviridae . E. huxleyi exhibits a haplodiploid life cycle; the calcified diploid stage is non-motile and forms extensive blooms. The haploid phase is a non-calcified biflagellated cell bearing organic scales. Haploid cells are thought to resist infection, through a process deemed the "Cheshire Cat" escape strategy; however, a recent study detected the presence of viral lipids in the same haploid strain. Here we report on the application of an E. huxleyi CCMP1516 EhV-86 combined tiling array (TA) that further confirms an EhV infection in the RCC1217 haploid strain, which grew without any signs of cell lysis. Reverse transcription polymerase chain reaction (RT-PCR) and PCR verified the presence of viral RNA in the haploid cells, yet indicated an absence of viral DNA, respectively. These infected cells are an alternative stage of the virus life cycle deemed the haplococcolithovirocell. In this instance, the host is both resistant to and infected by EhV, i.e., the viral transcriptome is present in haploid cells whilst there is no evidence of viral lysis. This superimposed state is reminiscent of Schrödinger's cat; of being simultaneously both dead and alive.

  11. Schrödinger’s Cheshire Cat: Are Haploid Emiliania huxleyi Cells Resistant to Viral Infection or Not?

    Science.gov (United States)

    Mordecai, Gideon J.; Verret, Frederic; Highfield, Andrea; Schroeder, Declan C.

    2017-01-01

    Emiliania huxleyi is the main calcite producer on Earth and is routinely infected by a virus (EhV); a double stranded DNA (dsDNA) virus belonging to the family Phycodnaviridae. E. huxleyi exhibits a haplodiploid life cycle; the calcified diploid stage is non-motile and forms extensive blooms. The haploid phase is a non-calcified biflagellated cell bearing organic scales. Haploid cells are thought to resist infection, through a process deemed the “Cheshire Cat” escape strategy; however, a recent study detected the presence of viral lipids in the same haploid strain. Here we report on the application of an E. huxleyi CCMP1516 EhV-86 combined tiling array (TA) that further confirms an EhV infection in the RCC1217 haploid strain, which grew without any signs of cell lysis. Reverse transcription polymerase chain reaction (RT-PCR) and PCR verified the presence of viral RNA in the haploid cells, yet indicated an absence of viral DNA, respectively. These infected cells are an alternative stage of the virus life cycle deemed the haplococcolithovirocell. In this instance, the host is both resistant to and infected by EhV, i.e., the viral transcriptome is present in haploid cells whilst there is no evidence of viral lysis. This superimposed state is reminiscent of Schrödinger’s cat; of being simultaneously both dead and alive. PMID:28335465

  12. Isolating Sperm from Cell Mixtures Using Magnetic Beads Coupled with an Anti-PH-20 Antibody for Forensic DNA Analysis.

    Directory of Open Access Journals (Sweden)

    Xing-Chun Zhao

    Full Text Available Vaginal swabs taken in rape cases usually contain epithelial cells from the victim and sperm from the assailant and forensic DNA analysis requires separation of sperm from these cell mixtures. PH-20, which is a glycosylphosphatidylinositol-anchored hyaluronidase located on the head of sperm, has important functions in fertilization. Here we describe a newly developed method for sperm isolation using anti-PH-20 antibody-coupled immunomagnetic beads (anti-PH-20 IMBs. Optical microscopy and scanning electron microscopy showed the IMBs recognized the head of sperm specifically and exhibited a great capacity to capture sperm cells. However, we found it necessary to incubate the IMB-sperm complex with DNase I before sperm lysis in order to remove any female DNA completely. We compared the sensitivity of anti-PH-20 IMBs in sperm and epithelial cell discrimination to those coated with a different anti-sperm antibody (anti-SP-10, anti-ADAM2 or anti-JLP. Only the anti-PH-20 IMBs succeeded in isolating sperm from cell mixtures at a sperm/epithelial cell ratio of 103:105. Further, our method exhibited greater power and better stability for sperm isolation compared to the traditional differential lysis strategy. Taken together, the anti-PH-20 IMB method described here could be effective for the isolation of sperm needed to obtain a single-sourced DNA profile as an aid to identifying the perpetrator in sexual assault cases.

  13. Raman spectroscopy for grading of live osteosarcoma cells.

    Science.gov (United States)

    Chiang, Yi-Hung; Wu, Stewart H; Kuo, Yi-Chun; Chen, How-Foo; Chiou, Arthur; Lee, Oscar K

    2015-04-18

    Osteosarcoma is the most common primary malignant bone tumor, and the grading of osteosarcoma cells relies on traditional histopathology and molecular biology methods, which require RNA extraction, protein isolation and immunohistological staining. All these methods require cell isolation, lysis or fixation, which is time-consuming and requires certain amount of tumor specimen. In this study, we report the use of Raman spectroscopy for grading of malignant osteosarcoma cells. We demonstrate that, based on the detection of differential production of mineral species, Raman spectroscopy can be used as a live cell analyzer to accurately assess the grades of osteosarcoma cells by evaluating their mineralization levels. Mineralization level was assessed by measuring amount of hydroxyapatite (HA), which is highly expressed in mature osteoblasts, but not in poorly differentiated osteosarcoma cell or mesenchymal stem cells, the putative cell-of-origin of osteosarcoma. We found that under Raman spectroscopy, the level of HA production was high in MG-63 cells, which are low-grade. Moreover, hydroxyapatite production was low in high-grade osteosarcoma cells such as 143B and SaOS2 cells (p Raman spectroscopy for the measurement of HA production by the protocol reported in this study may serve as a useful tool to rapidly and accurately assess the degree of malignancy in osteosarcoma cells in a label-free manner. Such application may shorten the period of pathological diagnosis and may benefit patients who are inflicted with osteosarcoma.

  14. Tumor Therapeutics Work as Stress Inducers to Enhance Tumor Sensitivity to Natural Killer (NK) Cell Cytolysis by Up-regulating NKp30 Ligand B7-H6.

    Science.gov (United States)

    Cao, Guoshuai; Wang, Jian; Zheng, Xiaodong; Wei, Haiming; Tian, Zhigang; Sun, Rui

    2015-12-11

    Immune cells are believed to participate in initiating anti-tumor effects during regular tumor therapy such as chemotherapy, radiation, hyperthermia, and cytokine injection. One of the mechanisms underlying this process is the expression of so-called stress-inducible immunostimulating ligands. Although the activating receptor NKG2D has been proven to play roles in tumor therapy through targeting its ligands, the role of NKp30, another key activating receptor, is seldom addressed. In this study, we found that the NKp30 ligand B7-H6 was widely expressed in tumor cells and closely correlated to their susceptibility to NK cell lysis. Further studies showed that treatment of tumor cells with almost all standard tumor therapeutics, including chemotherapy (cisplatin, 5-fluorouracil), radiation therapy, non-lethal heat shock, and cytokine therapy (TNF-α), could up-regulate the expression of B7-H6 in tumor cells and enhance tumor sensitivity to NK cell cytolysis. B7-H6 shRNA treatment effectively dampened sensitization of tumor cells to NK-mediated lysis. Our study not only reveals the possibility that tumor therapeutics work as stress inducers to enhance tumor sensitivity to NK cell cytolysis but also suggests that B7-H6 could be a potential target for tumor therapy in the future. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  15. Improved Activation toward Primary Colorectal Cancer Cells by Antigen-Specific Targeting Autologous Cytokine-Induced Killer Cells

    Directory of Open Access Journals (Sweden)

    Claudia Schlimper

    2012-01-01

    Full Text Available Adoptive therapy of malignant diseases with cytokine-induced killer (CIK cells showed promise in a number of trials; the activation of CIK cells from cancer patients towards their autologous cancer cells still needs to be improved. Here, we generated CIK cells ex vivo from blood lymphocytes of colorectal cancer patients and engineered those cells with a chimeric antigen receptor (CAR with an antibody-defined specificity for carcinoembryonic antigen (CEA. CIK cells thereby gained a new specificity as defined by the CAR and showed increase in activation towards CEA+ colon carcinoma cells, but less in presence of CEA− cells, indicated by increased secretion of proinflammatory cytokines. Redirected CIK activation was superior by CAR-mediated CD28-CD3ζ than CD3ζ signaling only. CAR-engineered CIK cells from colon carcinoma patients showed improved activation against their autologous, primary carcinoma cells from biopsies resulting in more efficient tumour cell lysis. We assume that adoptive therapy with CAR-modified CIK cells shows improved selectivity in targeting autologous tumour lesions.

  16. Mechanisms of diminished natural killer cell activity in pregnant women and neonates

    International Nuclear Information System (INIS)

    Baley, J.E.; Schacter, B.Z.

    1985-01-01

    Because alterations in natural killer (NK) activity in the perinatal period may be important in the maintenance of a healthy pregnancy, the mechanisms by which these alterations are mediated in neonates and in pregnant and postpartum women was examined. NK activity, as measured in a 4-hr 51 Cr-release assay and compared with adult controls, is significantly diminished in all three trimesters of pregnancy and in immediately postpartum women. In postpartum women, NK activity appears to be higher than in pregnant women, although this does not reach statistical significance. Pregnant and postpartum women have normal numbers of large granular lymphocytes and normal target cell binding in an agarose single cell assay but decreased lysis of the bound target cells. NK activity of mononuclear cells from postpartum women, in addition, demonstrate a shift in distribution to higher levels of resistance to gamma-irradiation. Further, sera from postpartum women cause a similar shift to increased radioresistance in mononuclear cells from adult controls. Because radioresistance is a property of interleukin 2-stimulated NK, the shift to radioresistance may represent lymphokine-mediated stimulation occurring during parturition. In contrast, cord blood cells have a more profound decrease in NK activity as determined by 51 Cr-release assay and decreases in both binding and lysis of bound target cells in the single cell assay. The resistance of NK activity in cord cells to gamma-irradiation is also increased, as seen in postpartum women. Cord blood serum, however, did not alter radioresistance or inhibit NK activity. The results suggest that the observed diminished NK activity in pregnant women and neonates arise by different mechanisms: an absence of mature NK cells in the neonate and an alteration of the NK cell in pregnancy leading to decreased killing

  17. Management of Pediatric Tumor Lysis Syndrome

    African Journals Online (AJOL)

    Urate oxidase in prevention and treatment of hyperuricemia associated with lymphoid malignancies. Leukemia. 1997. Nov;11(11):1813-6. 43. Elitek [package insert]. Bridgewater, NJ: Sanofi-. Aventis US LLC; 2009. 44. Pui CH, Mahmoud HH, Wiley JM, Woods GM,. Leverger G, Camitta B, Hastings C, Blaney SM, Relling.

  18. Comprehensive analysis of signal transduction in three-dimensional ECM-based tumor cell cultures

    Directory of Open Access Journals (Sweden)

    Iris Eke

    2015-11-01

    Full Text Available Analysis of signal transduction and protein phosphorylation is fundamental to understand physiological and pathological cell behavior as well as identification of novel therapeutic targets. Despite the fact that more physiological three-dimensional cell culture assays are increasingly used, particularly proteomics and phosphoproteomics remain challenging due to easy, robust and reproducible sample preparation. Here, we present an easy-to-perform, reliable and time-efficient method for the production of 3D cell lysates without compromising cell adhesion before cell lysis. The samples can be used for Western blotting as well as phosphoproteome array technology. This technique would be of interest for researchers working in all fields of biology and drug development.

  19. Immunologic targeting of FOXP3 in inflammatory breast cancer cells.

    Directory of Open Access Journals (Sweden)

    Smita Nair

    Full Text Available The forkhead transcription factor FOXP3 is necessary for induction of regulatory T lymphocytes (Tregs and their immunosuppressive function. We have previously demonstrated that targeting Tregs by vaccination of mice with murine FOXP3 mRNA-transfected dendritic cells (DCs elicits FOXP3-specific T cell responses and enhances tumor immunity. It is clear that FOXP3 expression is not restricted to T-cell lineage and herein, using RT-PCR, flow cytometry, and western immunoblot we demonstrate for the first time that FOXP3 is expressed in inflammatory breast cancer (IBC cells, SUM149 (triple negative, ErbB1-activated and SUM190 (ErbB2-overexpressing. Importantly, FOXP3-specific T cells generated in vitro using human FOXP3 RNA-transfected DCs as stimulators efficiently lyse SUM149 cells. Interestingly, an isogenic model (rSUM149 derived from SUM149 with an enhanced anti-apoptotic phenotype was resistant to FOXP3-specific T cell mediated lysis. The MHC class I cellular processing mechanism was intact in both cell lines at the protein and transcription levels suggesting that the resistance to cytolysis by rSUM149 cells was not related to MHC class I expression or to the MHC class I antigen processing machinery in these cells. Our data suggest that FOXP3 may be an effective tumor target in IBC cells however increased anti-apoptotic signaling can lead to immune evasion.

  20. Enzymatic cell disruption of microalgae biomass in biorefinery processes.

    Science.gov (United States)

    Demuez, Marie; Mahdy, Ahmed; Tomás-Pejó, Elia; González-Fernández, Cristina; Ballesteros, Mercedes

    2015-10-01

    When employing biotechnological processes for the procurement of biofuels and bio-products from microalgae, one of the most critical steps affecting economy and yields is the "cell disruption" stage. Currently, enzymatic cell disruption has delivered effective and cost competitive results when compared to mechanical and chemical cell disruption methods. However, the introduction of enzymes implies additional associated cost within the overall process. In order to reduce this cost, autolysis of microalgae is proposed as alternative enzymatic cell disruption method. This review aims to provide the state of the art of enzymatic cell disruption treatments employed in biorefinery processes and highlights the use of endopeptidases. During the enzymatic processes of microalgae life cycle, some lytic enzymes involved in cell division and programmed cell death have been proven useful in performing cell lysis. In this context, the role of endopeptidases is emphasized. Mirroring these natural events, an alternative cell disruption approach is proposed and described with the potential to induce the autolysis process using intrinsic cell enzymes. Integrating induced autolysis within biofuel production processes offers a promising approach to reduce overall global costs and energetic input associated with those of current cell disruption methods. A number of options for further inquiry are also discussed. © 2015 Wiley Periodicals, Inc.

  1. Differences in Purinergic Amplification of Osmotic Cell Lysis by the Pore-Forming RTX Toxins Bordetella pertussis CyaA and Actinobacillus pleuropneumoniae ApxIA: the Role of Pore Size

    Czech Academy of Sciences Publication Activity Database

    Mašín, Jiří; Fišer, Radovan; Linhartová, Irena; Osička, Radim; Bumba, Ladislav; Hewlett, E. L.; Benz, R.; Šebo, Peter

    2013-01-01

    Roč. 81, č. 12 (2013), s. 4571-4582 ISSN 0019-9567 R&D Projects: GA ČR GAP302/12/0460; GA ČR(CZ) GAP302/11/0580; GA ČR(CZ) GAP207/11/0717; GA AV ČR IAA500200914; GA ČR GA13-14547S Institutional support: RVO:61388971 Keywords : Bordetella pertussis * Actinobacillus pleuropneumoniae * E- coli Subject RIV: EE - Microbiology, Virology Impact factor: 4.156, year: 2013

  2. Deficiency in L-serine deaminase interferes with one-carbon metabolism and cell wall synthesis in Escherichia coli K-12.

    Science.gov (United States)

    Zhang, Xiao; El-Hajj, Ziad W; Newman, Elaine

    2010-10-01

    Escherichia coli K-12 provided with glucose and a mixture of amino acids depletes L-serine more quickly than any other amino acid even in the presence of ammonium sulfate. A mutant without three 4Fe4S L-serine deaminases (SdaA, SdaB, and TdcG) of E. coli K-12 is unable to do this. The high level of L-serine that accumulates when such a mutant is exposed to amino acid mixtures starves the cells for C(1) units and interferes with cell wall synthesis. We suggest that at high concentrations, L-serine decreases synthesis of UDP-N-acetylmuramate-L-alanine by the murC-encoded ligase, weakening the cell wall and producing misshapen cells and lysis. The inhibition by high L-serine is overcome in several ways: by a large concentration of L-alanine, by overproducing MurC together with a low concentration of L-alanine, and by overproducing FtsW, thus promoting septal assembly and also by overexpression of the glycine cleavage operon. S-Adenosylmethionine reduces lysis and allows an extensive increase in biomass without improving cell division. This suggests that E. coli has a metabolic trigger for cell division. Without that reaction, if no other inhibition occurs, other metabolic functions can continue and cells can elongate and replicate their DNA, reaching at least 180 times their usual length, but cannot divide.

  3. Deficiency in l-Serine Deaminase Interferes with One-Carbon Metabolism and Cell Wall Synthesis in Escherichia coli K-12▿

    Science.gov (United States)

    Zhang, Xiao; El-Hajj, Ziad W.; Newman, Elaine

    2010-01-01

    Escherichia coli K-12 provided with glucose and a mixture of amino acids depletes l-serine more quickly than any other amino acid even in the presence of ammonium sulfate. A mutant without three 4Fe4S l-serine deaminases (SdaA, SdaB, and TdcG) of E. coli K-12 is unable to do this. The high level of l-serine that accumulates when such a mutant is exposed to amino acid mixtures starves the cells for C1 units and interferes with cell wall synthesis. We suggest that at high concentrations, l-serine decreases synthesis of UDP-N-acetylmuramate-l-alanine by the murC-encoded ligase, weakening the cell wall and producing misshapen cells and lysis. The inhibition by high l-serine is overcome in several ways: by a large concentration of l-alanine, by overproducing MurC together with a low concentration of l-alanine, and by overproducing FtsW, thus promoting septal assembly and also by overexpression of the glycine cleavage operon. S-Adenosylmethionine reduces lysis and allows an extensive increase in biomass without improving cell division. This suggests that E. coli has a metabolic trigger for cell division. Without that reaction, if no other inhibition occurs, other metabolic functions can continue and cells can elongate and replicate their DNA, reaching at least 180 times their usual length, but cannot divide. PMID:20729359

  4. Neodymium-YAG laser vitreolysis in sickle cell retinopathy

    Energy Technology Data Exchange (ETDEWEB)

    Hrisomalos, N.F.; Jampol, L.M.; Moriarty, B.J.; Serjeant, G.; Acheson, R.; Goldberg, M.F.

    1987-08-01

    Six patients with proliferative sickle cell retinopathy and vitreous bands were treated with the neodymium-YAG (Nd-YAG) laser to accomplish lysis of avascular traction bands or to clear the media in front of the macula. Transection of bands was possible in five of the six cases but in two of these the effect was only partial. Three cases were satisfactorily treated with the Nd-YAG laser application alone, two eventually required conventional vitreoretinal surgery, and one patient's condition stabilized despite failure of the treatment. Complications from the treatment occurred in three cases and included subretinal (choroidal) hemorrhage, preretinal hemorrhage, microperforation of a retinal vein, and focal areas of damage to the retinal pigment epithelium. Neodymium-YAG vitreolysis may be a useful modality in carefully selected patients with proliferative sickle cell retinopathy, but potentially sight-threatening complications may occur.

  5. An adhesion-based method for plasma membrane isolation: evaluating cholesterol extraction from cells and their membranes.

    Science.gov (United States)

    Bezrukov, Ludmila; Blank, Paul S; Polozov, Ivan V; Zimmerberg, Joshua

    2009-11-15

    A method to isolate large quantities of directly accessible plasma membrane from attached cells is presented. The method is based on the adhesion of cells to an adsorbed layer of polylysine on glass plates, followed by hypotonic lysis with ice-cold distilled water and subsequent washing steps. Optimal conditions for coating glass plates and time for cell attachment were established. No additional chemical or mechanical treatments were used. Contamination of the isolated plasma membrane by cell organelles was less than 5%. The method uses inexpensive, commercially available polylysine and reusable glass plates. Plasma membrane preparations can be made in 15 min. Using this method, we determined that methyl-beta-cyclodextrin differentially extracts cholesterol from fibroblast cells and their plasma membranes and that these differences are temperature dependent. Determination of the cholesterol/phospholipid ratio from intact cells does not reflect methyl-beta-cyclodextrin plasma membrane extraction properties.

  6. The Natural Killer Cell Cytotoxic Function Is Modulated by HIV-1 Accessory Proteins

    Directory of Open Access Journals (Sweden)

    Edward Barker

    2011-07-01

    Full Text Available Natural killer (NK cells’ major role in the control of viruses is to eliminate established infected cells. The capacity of NK cells to kill virus-infected cells is dependent on the interactions between ligands on the infected cell and receptors on the NK cell surface. Because of the importance of ligand-receptor interactions in modulating the NK cell cytotoxic response, HIV has developed strategies to regulate various NK cell ligands making the infected cell surprisingly refractory to NK cell lysis. This is perplexing because the HIV-1 accessory protein Vpr induces expression of ligands for the NK cell activating receptor, NKG2D. In addition, the accessory protein Nef removes the inhibitory ligands HLA-A and -B. The reason for the ineffective killing by NK cells despite the strong potential to eliminate infected cells is due to HIV-1 Vpu’s ability to down modulate the co-activation ligand, NTB-A, from the cell surface. Down modulation of NTB-A prevents efficient NK cell degranulation. This review will focus on the mechanisms through which the HIV-1 accessory proteins modulate their respective ligands, and its implication for NK cell killing of HIV-infected cells.

  7. Trypanosoma cruzi response to sterol biosynthesis inhibitors: morphophysiological alterations leading to cell death.

    Directory of Open Access Journals (Sweden)

    Rafael Luis Kessler

    Full Text Available The protozoan parasite Trypanosoma cruzi displays similarities to fungi in terms of its sterol lipid biosynthesis, as ergosterol and other 24-alkylated sterols are its principal endogenous sterols. The sterol pathway is thus a potential drug target for the treatment of Chagas disease. We describe here a comparative study of the growth inhibition, ultrastructural and physiological changes leading to the death of T. cruzi cells following treatment with the sterol biosynthesis inhibitors (SBIs ketoconazole and lovastatin. We first calculated the drug concentration inhibiting epimastigote growth by 50% (EC(50/72 h or killing all cells within 24 hours (EC(100/24 h. Incubation with inhibitors at the EC(50/72 h resulted in interesting morphological changes: intense proliferation of the inner mitochondrial membrane, which was corroborated by flow cytometry and confocal microscopy of the parasites stained with rhodamine 123, and strong swelling of the reservosomes, which was confirmed by acridine orange staining. These changes to the mitochondria and reservosomes may reflect the involvement of these organelles in ergosterol biosynthesis or the progressive autophagic process culminating in cell lysis after 6 to 7 days of treatment with SBIs at the EC(50/72 h. By contrast, treatment with SBIs at the EC(100/24 h resulted in rapid cell death with a necrotic phenotype: time-dependent cytosolic calcium overload, mitochondrial depolarization and reservosome membrane permeabilization (RMP, culminating in cell lysis after a few hours of drug exposure. We provide the first demonstration that RMP constitutes the "point of no return" in the cell death cascade, and propose a model for the necrotic cell death of T. cruzi. Thus, SBIs trigger cell death by different mechanisms, depending on the dose used, in T. cruzi. These findings shed new light on ergosterol biosynthesis and the mechanisms of programmed cell death in this ancient protozoan parasite.

  8. Cell wall glycans and soluble factors determine the interactions between the hyphae of Candida albicans and Pseudomonas aeruginosa.

    Science.gov (United States)

    Brand, Alexandra; Barnes, Julia D; Mackenzie, Kevin S; Odds, Frank C; Gow, Neil A R

    2008-10-01

    The fungus, Candida albicans, and the bacterium, Pseudomonas aeruginosa, are opportunistic human pathogens that have been coisolated from diverse body sites. Pseudomonas aeruginosa suppresses C. albicans proliferation in vitro and potentially in vivo but it is the C. albicans hyphae that are killed while yeast cells are not. We show that hyphal killing involves both contact-mediated and soluble factors. Bacterial culture filtrates contained heat-labile soluble factors that killed C. albicans hyphae. In cocultures, localized points of hyphal lysis were observed, suggesting that adhesion and subsequent bacteria-mediated cell wall lysis is involved in the killing of C. albicans hyphae. The glycosylation status of the C. albicans cell wall affected the rate of contact-dependent killing because mutants with severely truncated O-linked, but not N-linked, glycans were hypersensitive to Pseudomonas-mediated killing. Deletion of HWP1, ALS3 or HYR1, which encode major hypha-associated cell wall proteins, had no effect on fungal susceptibility.

  9. Evaluation of gene delivery strategies to efficiently overexpress functional HLA-G on human bone marrow stromal cells

    Directory of Open Access Journals (Sweden)

    Joana S Boura

    2014-01-01

    Full Text Available Mesenchymal stromal cells (MSC constitutively express low levels of human leukocyte antigen-G (HLA-G, which has been shown to contribute to their immunomodulatory and anti-inflammatory properties. Here, we hypothesized that overexpression of HLA-G on bone marrow-derived MSC would improve their immunomodulatory function, thus increasing their therapeutic potential. Therefore, we investigated which gene transfer system is best suited for delivering this molecule while maintaining its immunomodulatory effects. We performed a side-by-side comparison between three nonviral plasmid-based platforms (pmax-HLA-G1; MC-HLA-G1; pEP-HLA-G1 and a viral system (Lv-HLA-G1 using gene transfer parameters that yielded similar levels of HLA-G1-expressing MSC. Natural killer (NK cell–mediated lysis assays and T cell proliferation assays showed that MSC modified with the HLA-G1 expressing viral vector had significantly lower susceptibility to NK-lysis and significantly reduced T cell proliferation when compared to nonmodified cells or MSC modified with plasmid. We also show that, in plasmid-modified MSC, an increase in Toll-like receptor (TLR9 expression is the mechanism responsible for the abrogation of HLA-G1's immunomodulatory effect. Although MSC can be efficiently modified to overexpress HLA-G1 using viral and nonviral strategies, only viral-based delivery of HLA-G1 is suitable for improvement of MSC's immunomodulatory properties.

  10. DNA transfection of bone marrow mesenchymal stem cells using micro electroporation chips

    KAUST Repository

    Deng, Peigang

    2011-02-01

    Experimental study of electroporation of bone marrow mesenchymal stem cells (MSCs) at the single-cell level was carried out on a micro EP chip by using single electric rectangular pulse. The threshold values of the electrode potential and pulse width for gas bubble generation on the micro electrodes due to electrolysis of water were revealed as 4.5 volt and 100 μs, respectively. Quantitative EP study was performed with various electric field strengths for various pulse widths, ranging from 20μs to 15ms. Over 1,000 single-cell EP results were used to construct an EP "phase diagram", which delineates the boundaries for (1) effective EP of MSCs and (2) electric cell lysis of MSCs. Finally, the micro EP chip showed successful transfection of the pEGFP-C1 plasmid into the MSCs by properly choosing the electric parameters from the EP "phase diagram". © 2011 IEEE.

  11. DNA transfection of bone marrow mesenchymal stem cells using micro electroporation chips

    KAUST Repository

    Deng, Peigang; Chang, Donald C.; Lee, Yi Kuen; Zhou, Junwei; Li, Gang

    2011-01-01

    Experimental study of electroporation of bone marrow mesenchymal stem cells (MSCs) at the single-cell level was carried out on a micro EP chip by using single electric rectangular pulse. The threshold values of the electrode potential and pulse width for gas bubble generation on the micro electrodes due to electrolysis of water were revealed as 4.5 volt and 100 μs, respectively. Quantitative EP study was performed with various electric field strengths for various pulse widths, ranging from 20μs to 15ms. Over 1,000 single-cell EP results were used to construct an EP "phase diagram", which delineates the boundaries for (1) effective EP of MSCs and (2) electric cell lysis of MSCs. Finally, the micro EP chip showed successful transfection of the pEGFP-C1 plasmid into the MSCs by properly choosing the electric parameters from the EP "phase diagram". © 2011 IEEE.

  12. Essentials of single-cell analysis concepts, applications and future prospects

    CERN Document Server

    Santra, Tuhin

    2016-01-01

    This book provides an overview of single-cell isolation, separation, injection, lysis and dynamics analysis as well as a study of their heterogeneity using different miniaturized devices. As an important part of single-cell analysis, different techniques including electroporation, microinjection, optical trapping, optoporation, rapid electrokinetic patterning and optoelectronic tweezers are described in detail. It presents different fluidic systems (e.g. continuous micro/nano-fluidic devices, microfluidic cytometry) and their integration with sensor technology, optical and hydrodynamic stretchers etc., and demonstrates the applications of single-cell analysis in systems biology, proteomics, genomics, epigenomics, cancer transcriptomics, metabolomics, biomedicine and drug delivery systems. It also discusses the future challenges for single-cell analysis, including the advantages and limitations. This book is enjoyable reading material while at the same time providing essential information to scientists in acad...

  13. Recent advances in whole cell biocatalysis techniques bridging from investigative to industrial scale.

    Science.gov (United States)

    Wachtmeister, Jochen; Rother, Dörte

    2016-12-01

    Recent advances in biocatalysis have strongly boosted its recognition as a valuable addition to traditional chemical synthesis routes. As for any catalytic process, catalyst's costs and stabilities are of highest relevance for the economic application in chemical manufacturing. Employing biocatalysts as whole cells circumvents the need of cell lysis and enzyme purification and hence strongly cuts on cost. At the same time, residual cell wall components can shield the entrapped enzyme from potentially harmful surroundings and aid to enable applications far from natural enzymatic environments. Further advantages are the close proximity of reactants and catalysts as well as the inherent presence of expensive cofactors. Here, we review and comment on benefits and recent advances in whole cell biocatalysis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Stem Cell-Based Cell Carrier for Targeted Oncolytic Virotherapy: Translational Opportunity and Open Questions

    Directory of Open Access Journals (Sweden)

    Janice Kim

    2015-11-01

    Full Text Available Oncolytic virotherapy for cancer is an innovative therapeutic option where the ability of a virus to promote cell lysis is harnessed and reprogrammed to selectively destroy cancer cells. Such treatment modalities exhibited antitumor activity in preclinical and clinical settings and appear to be well tolerated when tested in clinical trials. However, the clinical success of oncolytic virotherapy has been significantly hampered due to the inability to target systematic metastasis. This is partly due to the inability of the therapeutic virus to survive in the patient circulation, in order to target tumors at distant sites. An early study from various laboratories demonstrated that cells infected with oncolytic virus can protect the therapeutic payload form the host immune system as well as function as factories for virus production and enhance the therapeutic efficacy of oncolytic virus. While a variety of cell lineages possessed potential as cell carriers, copious investigation has established stem cells as a very attractive cell carrier system in oncolytic virotherapy. The ideal cell carrier desire to be susceptible to viral infection as well as support viral infection, maintain immunosuppressive properties to shield the loaded viruses from the host immune system, and most importantly possess an intrinsic tumor homing ability to deliver loaded viruses directly to the site of the metastasis—all qualities stem cells exhibit. In this review, we summarize the recent work in the development of stem cell-based carrier for oncolytic virotherapy, discuss the advantages and disadvantages of a variety of cell carriers, especially focusing on why stem cells have emerged as the leading candidate, and finally propose a future direction for stem cell-based targeted oncolytic virotherapy that involves its establishment as a viable treatment option for cancer patients in the clinical setting.

  15. Adenovirus-dependent changes in cell membrane permeability: role of Na/sup +/, K/sup +/-ATPase

    Energy Technology Data Exchange (ETDEWEB)

    Seth, P.; Pastan, I.; Willingham, M.C.

    1987-03-01

    Adenovirus-dependent release of choline phosphate from KB cells at pH 6.0 was partially blocked by ouabain. In K/sup +/-containing medium, maximum inhibition of release was obtained by 10/sup -5/ M ouabain and half-maximal inhibition was achieved by about 0.5 x 10/sup -6/ M ouabain. Ouabain did not block either the binding or the uptake of adenovirus by KB cells. Without K/sup +/, about 25% of cell-associated choline phosphate was released by adenovirus, whereas with 1 mM K/sup +/ about 50% was released. This activation by K/sup +/ was blocked by 0.1 mM ouabain. HeLa cells behaved like KB cells, but a mutant of HeLa cells resistant to ouabain (D98-OR) released much lower amounts of choline phosphate in response to human adenovirus type 2 (Ad2). Wild-type D98-OR cells bound nearly the same amount of adenovirus as did normal HeLa cells. Ad2 also increased the activity of Na/sup +/, K/sup +/-ATPase in KB cells, with maximum activation at 50..mu..g of Ad2 per ml. In D98-OR cells, Ad2 failed to activate Na/sup +/, K/sup +/, ATPase activity. Ad2-dependent lysis of endocytic vesicles (receptosomes) was assayed by measuring Ad2-dependent enhancement of epidermal growth factor-Pseudomonas exotoxin toxicity. This action of adenovirus was increased when K/sup +/ was present in the medium. Under the conditions used, K/sup +/ had no effect on the amount of Ad2 or epidermal growth factor taken up by the cells. On the basis of these results, it is suggested that Ad2-dependent cellular efflux of choline phosphate and adenovirus-dependent lysis of receptosomes may require Na/sup +/, K/sup +/-ATPase activity.

  16. CD16xCD33 bispecific killer cell engager (BiKE) activates NK cells against primary MDS and MDSC CD33+ targets.

    Science.gov (United States)

    Gleason, Michelle K; Ross, Julie A; Warlick, Erica D; Lund, Troy C; Verneris, Michael R; Wiernik, Andres; Spellman, Stephen; Haagenson, Michael D; Lenvik, Alexander J; Litzow, Mark R; Epling-Burnette, Pearlie K; Blazar, Bruce R; Weiner, Louis M; Weisdorf, Daniel J; Vallera, Daniel A; Miller, Jeffrey S

    2014-05-08

    Myelodysplastic syndromes (MDS) are stem cell disorders that can progress to acute myeloid leukemia. Although hematopoietic cell transplantation can be curative, additional therapies are needed for a disease that disproportionally afflicts the elderly. We tested the ability of a CD16xCD33 BiKE to induce natural killer (NK) cell function in 67 MDS patients. Compared with age-matched normal controls, CD7(+) lymphocytes, NK cells, and CD16 expression were markedly decreased in MDS patients. Despite this, reverse antibody-dependent cell-mediated cytotoxicity assays showed potent degranulation and cytokine production when resting MDS-NK cells were triggered with an agonistic CD16 monoclonal antibody. Blood and marrow MDS-NK cells treated with bispecific killer cell engager (BiKE) significantly enhanced degranulation and tumor necrosis factor-α and interferon-γ production against HL-60 and endogenous CD33(+) MDS targets. MDS patients had a significantly increased proportion of immunosuppressive CD33(+) myeloid-derived suppressor cells (MDSCs) that negatively correlated with MDS lymphocyte populations and CD16 loss on NK cells. Treatment with the CD16xCD33 BiKE successfully reversed MDSC immunosuppression of NK cells and induced MDSC target cell lysis. Lastly, the BiKE induced optimal MDS-NK cell function irrespective of disease stage. Our data suggest that the CD16xCD33 BiKE functions against both CD33(+) MDS and MDSC targets and may be therapeutically beneficial for MDS patients.

  17. Ibrutinib interferes with the cell-mediated anti-tumor activities of therapeutic CD20 antibodies: implications for combination therapy

    DEFF Research Database (Denmark)

    Da Roit, F.; Engelberts, P. J.; Taylor, R. P.

    2015-01-01

    The novel Bruton tyrosine kinase inhibitor ibrutinib and phosphatidyl-4-5-biphosphate 3-kinase-delta inhibitor idelalisib are promising drugs for the treatment of chronic lymphocytic leukemia and B-cell non-Hodgkin lymphoma, either alone or in combination with anti-CD20 antibodies. We investigated...... the possible positive or negative impact of these drugs on all known mechanisms of action of both type I and type II anti-CD20 antibodies. Pretreatment with ibrutinib for 1 hour did not increase direct cell death of cell lines or chronic lymphocytic leukemia samples mediated by anti-CD20 antibodies. Pre......-treatment with ibrutinib did not inhibit complement activation or complement-mediated lysis. In contrast, ibrutinib strongly inhibited all cell-mediated mechanisms induced by anti-CD20 antibodies rituximab, ofatumumab or obinutuzumab, either in purified systems or whole blood assays. Activation of natural killer cells...

  18. A buccal cell model comet assay: Development and evaluation for human biomonitoring and nutritional studies

    Energy Technology Data Exchange (ETDEWEB)

    Szeto, Y.T. [Department of Health Technology and Informatics, Hong Kong Polytechnic University, Kowloon, Hong Kong (China); School of Health Sciences, Macao Polytechnic Institute, Macao (China); Benzie, I.F.F. [Department of Health Technology and Informatics, Hong Kong Polytechnic University, Kowloon, Hong Kong (China)]. E-mail: iris.benzie@inet.polyu.edu.hk; Collins, A.R. [Department of Nutrition, University of Oslo, Oslo (Norway); Choi, S.W. [Department of Health Technology and Informatics, Hong Kong Polytechnic University, Kowloon, Hong Kong (China); Cheng, C.Y. [Department of Health Technology and Informatics, Hong Kong Polytechnic University, Kowloon, Hong Kong (China); Yow, C.M.N. [Department of Health Technology and Informatics, Hong Kong Polytechnic University, Kowloon, Hong Kong (China); Tse, M.M.Y. [School of Nursing, Hong Kong Polytechnic University, Kowloon, Hong Kong (China)

    2005-10-15

    The comet assay is a widely used biomonitoring tool for DNA damage. The most commonly used cells in human studies are lymphocytes. There is an urgent need to find an alternative target human cell that can be collected from normal subjects with minimal invasion. There are some reports of buccal cells, collected easily from the inside of the mouth, being used in studies of DNA damage and repair, and these were of interest. However, our preliminary studies following the published protocol showed that buccal cells sustained massive damage and disintegrated at the high pH [O. Ostling, K.J. Johanson. Microelectrophoretic study of radiation-induced DNA damages in individual mammalian cells. Biochem. Biophys. Res. Commun. 123 (1984) 291-298] used, but that at lower pH were extremely resistant to lysis, an essential step in the comet assay. Therefore, the aims of this study were to develop a protocol than enabled buccal cell lysis and DNA damage testing in the comet assay, and to use the model to evaluate the potential use of the buccal cell model in human biomonitoring and nutritional study. Specifically, we aimed to investigate intra- and inter-individual differences in buccal cell DNA damage (as strand breaks), the effect of in vitro exposure to both a standard oxidant challenge and antioxidant treatment, as well as in situ exposure to an antioxidant-rich beverage and supplementation-related effects using a carotenoid-rich food. Successful lysis was achieved using 0.25% trypsin for 30 min followed by proteinase K (1 mg/ml) treatment for 60 min. When this procedure was performed on cells pre-embedded in agarose on a microscope slide, followed by electrophoresis (in 0.01 M NaOH, 1 mM EDTA, pH 9.1, 18 min at 12 V), a satisfactory comet image was obtained, though inter-individual variation was quite wide. Pre-lysis exposure of cells to a standard oxidant challenge (induced by H{sub 2}O{sub 2}) increased DNA strand breaks in a dose related manner, and incubation of cells in

  19. A buccal cell model comet assay: Development and evaluation for human biomonitoring and nutritional studies

    International Nuclear Information System (INIS)

    Szeto, Y.T.; Benzie, I.F.F.; Collins, A.R.; Choi, S.W.; Cheng, C.Y.; Yow, C.M.N.; Tse, M.M.Y.

    2005-01-01

    The comet assay is a widely used biomonitoring tool for DNA damage. The most commonly used cells in human studies are lymphocytes. There is an urgent need to find an alternative target human cell that can be collected from normal subjects with minimal invasion. There are some reports of buccal cells, collected easily from the inside of the mouth, being used in studies of DNA damage and repair, and these were of interest. However, our preliminary studies following the published protocol showed that buccal cells sustained massive damage and disintegrated at the high pH [O. Ostling, K.J. Johanson. Microelectrophoretic study of radiation-induced DNA damages in individual mammalian cells. Biochem. Biophys. Res. Commun. 123 (1984) 291-298] used, but that at lower pH were extremely resistant to lysis, an essential step in the comet assay. Therefore, the aims of this study were to develop a protocol than enabled buccal cell lysis and DNA damage testing in the comet assay, and to use the model to evaluate the potential use of the buccal cell model in human biomonitoring and nutritional study. Specifically, we aimed to investigate intra- and inter-individual differences in buccal cell DNA damage (as strand breaks), the effect of in vitro exposure to both a standard oxidant challenge and antioxidant treatment, as well as in situ exposure to an antioxidant-rich beverage and supplementation-related effects using a carotenoid-rich food. Successful lysis was achieved using 0.25% trypsin for 30 min followed by proteinase K (1 mg/ml) treatment for 60 min. When this procedure was performed on cells pre-embedded in agarose on a microscope slide, followed by electrophoresis (in 0.01 M NaOH, 1 mM EDTA, pH 9.1, 18 min at 12 V), a satisfactory comet image was obtained, though inter-individual variation was quite wide. Pre-lysis exposure of cells to a standard oxidant challenge (induced by H 2 O 2 ) increased DNA strand breaks in a dose related manner, and incubation of cells in Trolox

  20. Interaction between dendritic cells and natural killer cells during pregnancy in mice.

    Science.gov (United States)

    Blois, Sandra M; Barrientos, Gabriela; Garcia, Mariana G; Orsal, Arif S; Tometten, Mareike; Cordo-Russo, Rosalia I; Klapp, Burghard F; Santoni, Angela; Fernández, Nelson; Terness, Peter; Arck, Petra C

    2008-07-01

    A complex regulation of innate and adaptive immune responses at the maternal fetal interface promotes tolerance of trophoblast cells carrying paternally derived antigens. Such regulatory functions involve uterine dendritic cells (uDC) and natural killer (uNK) cells. The existence of a NK and DC "cross talk" has been revealed in various experimental settings; its biological significance ranging from cooperative stimulation to cell lysis. Little is known about the presence or role of NK and DC cross talk at the maternal fetal interface. The present study shows that mouse NK and DC interactions are subject to modulation by trophoblast cells in vitro. This interaction promotes a tolerogenic microenvironment characterized by downregulation of the expression of activation markers on uNK cells and uDC and dominance of Th2 cytokines. NK and DC interactions would also influence uterine cell proliferation and this process would be strongly modulated by trophoblast-derived signals. Indeed; while low proliferation rates were observed upon regular coculture allowing direct contact between uterine cells and trophoblasts, incubation in a transwell culture system markedly increased uterine cell proliferation suggesting that soluble factors are key mediators in the molecular "dialog" between the mother and the conceptus during the establishment of mouse pregnancy. Our data further reveal that the regulatory functions of trophoblast cells associated with tolerance induction are impaired in high abortion murine matings. Interestingly, we observed that secretion of interleukin-12p70 by uDC is dramatically abrogated in the presence of uNK cells. Taken together, our results provide the first evidence that a delicate balance of interactions involving NK cells, DC, and trophoblasts at the mouse maternal fetal interface supports a successful pregnancy outcome.

  1. The application of percutaneous lysis of epidural adhesions in patients with failed back surgery syndrome A aplicação da lise percutânea de aderências epidurais em pacientes com síndrome pós-laminectomia

    Directory of Open Access Journals (Sweden)

    He Chun-jing

    2012-04-01

    Full Text Available PURPOSE: To investigate the efficacy and the feasibility of application of percutaneous lysis of epidural adhesions in failed back surgery syndrome (FBSS using a stiff type guide wire and 4F vascular catheter. METHODS: Ninety two patients with FBSS were randomly divided into two groups, the control group (treated by injection dexamethasone only and percutaneous lysis of epidural adhesions group. Visual analog scale scores (VAS and therapeutic evaluation were observed in the preoperative, seven days postoperative, one month and six months postoperative. RESULTS: VAS scores for pain were significantly reduced in both groups at seven days. The VAS scores were in controlled group at one month, six months was significantly higher than that in epidural lysis group. However, there was no statistical difference in VAS scores of one month and six months when respectively compared to that of before operation in controlled group. Patients on epidural lysis reported clinical effectiveness rate was 50%. Patients on control was 5.26%, there was a statistical difference between two groups. CONCLUSION: Percutaneous lysis of epidural adhesions by using a stiff type guide wire and 4F vascular catheter is an effective method in the treatment of FBSS and it has a value in clinical application.OBJETIVO: Investigar a eficácia e a exequibilidade da aplicação da lise percutânea de aderências epidurais na síndrome pós-laminectomia usando um fio-guia tipo Stiff e um cateter vascular 4F. MÉTODOS: Noventa e dois pacientes com síndrome pós-laminectomia foram randomizados em dois grupos: grupo controle (tratado somente com injeção de dexametazona e grupo lise percutânea de aderências epidurais. Escores de escala visual analógica (VAS e avaliação terapêutica foram observadas no pré-operatório, no sétimo dia de pós-operatório, um mês e seis meses de pós-operatório. RESULTADOS: Escores VAS para dor foram significantemente reduzidos em ambos os grupos

  2. Cell vacuolation caused by Vibrio cholerae hemolysin.

    Science.gov (United States)

    Figueroa-Arredondo, P; Heuser, J E; Akopyants, N S; Morisaki, J H; Giono-Cerezo, S; Enríquez-Rincón, F; Berg, D E

    2001-03-01

    Non-O1 strains of Vibrio cholerae implicated in gastroenteritis and diarrhea generally lack virulence determinants such as cholera toxin that are characteristic of epidemic strains; the factors that contribute to their virulence are not understood. Here we report that at least one-third of diarrhea-associated nonepidemic V. cholerae strains from Mexico cause vacuolation of cultured Vero cells. Detailed analyses indicated that this vacuolation was related to that caused by aerolysin, a pore-forming toxin of Aeromonas; it involved primarily the endoplasmic reticulum at early times (approximately 1 to 4 h after exposure), and resulted in formation of large, acidic, endosome-like multivesicular vacuoles (probably autophagosomes) only at late times (approximately 16 h). In contrast to vacuolation caused by Helicobacter pylori VacA protein, that induced by V. cholerae was exacerbated by agents that block vacuolar proton pumping but not by endosome-targeted weak bases. It caused centripetal redistribution of endosomes, reflecting cytoplasmic alkalinization. The gene for V. cholerae vacuolating activity was cloned and was found to correspond to hlyA, the structural gene for hemolysin. HlyA protein is a pore-forming toxin that causes ion leakage and, ultimately, eukaryotic cell lysis. Thus, a distinct form of cell vacuolation precedes cytolysis at low doses of hemolysin. We propose that this vacuolation, in itself, contributes to the virulence of V. cholerae strains, perhaps by perturbing intracellular membrane trafficking or ion exchange in target cells and thereby affecting local intestinal inflammatory or other defense responses.

  3. Human CD4+ T cells lyse target cells via granzyme/perforin upon circumvention of MHC class II restriction by an antibody-like immunoreceptor.

    Science.gov (United States)

    Hombach, Andreas; Köhler, Heike; Rappl, Gunter; Abken, Hinrich

    2006-10-15

    Immune elimination of tumor cells requires the close cooperation between CD8+ CTL and CD4+ Th cells. We circumvent MHC class II-restriction of CD4+ T cells by expression of a recombinant immunoreceptor with an Ab-derived binding domain redirecting specificity. Human CD4+ T cells grafted with an immunoreceptor specific for carcinoembryonic Ag (CEA) are activated to proliferate and secrete cytokines upon binding to CEA+ target cells. Notably, redirected CD4+ T cells mediate cytolysis of CEA+ tumor cells with high efficiencies. Lysis by redirected CD4+ T cells is independent of death receptor signaling via TNF-alpha or Fas, but mediated by perforin and granzyme because cytolysis is inhibited by blocking the release of cytotoxic granules, but not by blocking of Fas ligand or TNF-alpha. CD4+ T cells redirected by Ab-derived immunoreceptors in a MHC class II-independent fashion substantially extend the power of an adoptive, Ag-triggered immunotherapy not only by CD4+ T cell help, but also by cytolytic effector functions. Because cytolysis is predominantly mediated via granzyme/perforin, target cells that are resistant to death receptor signaling become sensitive to a cytolytic attack by engineered CD4+ T cells.

  4. A Tetrameric Peptide Derived from Bovine Lactoferricin Exhibits Specific Cytotoxic Effects against Oral Squamous-Cell Carcinoma Cell Lines

    Directory of Open Access Journals (Sweden)

    Víctor A. Solarte

    2015-01-01

    Full Text Available Several short linear peptides derived from cyclic bovine lactoferricin were synthesized and tested for their cytotoxic effect against the oral cavity squamous-cell carcinoma (OSCC cell lines CAL27 and SCC15. As a control, an immortalized and nontumorigenic cell line, Het-1A, was used. Linear peptides based on the RRWQWR core sequence showed a moderate cytotoxic effect and specificity towards tumorigenic cells. A tetrameric peptide, LfcinB(20–254, containing the RRWQWR motif, exhibited greater cytotoxic activity (>90% in both OSCC cell lines compared to the linear lactoferricin peptide or the lactoferrin protein. Additionally, this tetrameric peptide showed the highest specificity towards tumorigenic cells among the tested peptides. Interestingly, this effect was very fast, with cell shrinkage, severe damage to cell membrane permeability, and lysis within one hour of treatment. Our results are consistent with a necrotic effect rather than an apoptotic one and suggest that this tetrameric peptide could be considered as a new candidate for the therapeutic treatment of OSCC.

  5. A Tetrameric Peptide Derived from Bovine Lactoferricin Exhibits Specific Cytotoxic Effects against Oral Squamous-Cell Carcinoma Cell Lines.

    Science.gov (United States)

    Solarte, Víctor A; Rosas, Jaiver E; Rivera, Zuly J; Arango-Rodríguez, Martha L; García, Javier E; Vernot, Jean-Paul

    2015-01-01

    Several short linear peptides derived from cyclic bovine lactoferricin were synthesized and tested for their cytotoxic effect against the oral cavity squamous-cell carcinoma (OSCC) cell lines CAL27 and SCC15. As a control, an immortalized and nontumorigenic cell line, Het-1A, was used. Linear peptides based on the RRWQWR core sequence showed a moderate cytotoxic effect and specificity towards tumorigenic cells. A tetrameric peptide, LfcinB(20-25)4, containing the RRWQWR motif, exhibited greater cytotoxic activity (>90%) in both OSCC cell lines compared to the linear lactoferricin peptide or the lactoferrin protein. Additionally, this tetrameric peptide showed the highest specificity towards tumorigenic cells among the tested peptides. Interestingly, this effect was very fast, with cell shrinkage, severe damage to cell membrane permeability, and lysis within one hour of treatment. Our results are consistent with a necrotic effect rather than an apoptotic one and suggest that this tetrameric peptide could be considered as a new candidate for the therapeutic treatment of OSCC.

  6. Differential responses of cells from human skin keratinocyte and bovine mammary epithelium to attack by pore-forming Staphylococcus aureus alpha-toxin.

    Science.gov (United States)

    Suriyaphol, Gunnaporn; Sarikaputi, Meena; Suriyaphol, Prapat

    2009-11-01

    Human skin keratinocytes HaCat attacked by Staphylococcus aureus alpha-toxin showed a transient drop of cellular ATP levels whereas in toxin-perforated bovine mammary epithelial cells (BMEC), the ATP levels dropped more slowly. Morphologically, during the ATP level depletion, HaCat cell developed a spacious intracellular vacuole together with the transient influx of trypan blue. WST-1 signal, which tested the function of mitochondrial enzyme in viable cells, also decreased concomitantly. On the other hand, BMEC excluded trypan blue and vacuolation was not observed throughout the experiment. We conclude that mammary epithelial cells resist the toxin better than keratinocytes. This is the first report showing that alpha-toxin enhances transient membrane permeability to large molecules, temporary vacuole formation and the transient defect of mitochondrial enzyme in viable cells without cell lysis.

  7. Secondary cell wall formation in Cryptococcus neoformans as a rescue mechanism against acid-induced autolysis.

    Science.gov (United States)

    Farkas, Vladimír; Takeo, Kanji; Maceková, Danka; Ohkusu, Misako; Yoshida, Soichi; Sipiczki, Matthias

    2009-03-01

    Growth of the opportunistic yeast pathogen Cryptococcus neoformans in a synthetic medium containing yeast nitrogen base and 1.0-3.0% glucose is accompanied by spontaneous acidification of the medium, with its pH decreasing from the initial 5.5 to around 2.5 in the stationary phase. During the transition from the late exponential to the stationary phase of growth, many cells died as a consequence of autolytic erosion of their cell walls. Simultaneously, there was an increase in an ecto-glucanase active towards beta-1,3-glucan and having a pH optimum between pH 3.0 and 3.5. As a response to cell wall degradation, some cells developed an unusual survival strategy by forming 'secondary' cell walls underneath the original ones. Electron microscopy revealed that the secondary cell walls were thicker than the primary ones, exposing bundles of polysaccharide microfibrils only partially masked by an amorphous cell wall matrix on their surfaces. The cells bearing secondary cell walls had a three to five times higher content of the alkali-insoluble cell wall polysaccharides glucan and chitin, and their chitin/glucan ratio was about twofold higher than in cells from the logarithmic phase of growth. The cell lysis and the formation of the secondary cell walls could be suppressed by buffering the growth medium between pH 4.5 and 6.5.

  8. Natural biased coin encoded in the genome determines cell strategy.

    Directory of Open Access Journals (Sweden)

    Faezeh Dorri

    Full Text Available Decision making at a cellular level determines different fates for isogenic cells. However, it is not yet clear how rational decisions are encoded in the genome, how they are transmitted to their offspring, and whether they evolve and become optimized throughout generations. In this paper, we use a game theoretic approach to explain how rational decisions are made in the presence of cooperators and competitors. Our results suggest the existence of an internal switch that operates as a biased coin. The biased coin is, in fact, a biochemical bistable network of interacting genes that can flip to one of its stable states in response to different environmental stimuli. We present a framework to describe how the positions of attractors in such a gene regulatory network correspond to the behavior of a rational player in a competing environment. We evaluate our model by considering lysis/lysogeny decision making of bacteriophage lambda in E. coli.

  9. Time-resolved, single-cell analysis of induced and programmed cell death via non-invasive propidium iodide and counterstain perfusion.

    Science.gov (United States)

    Krämer, Christina E M; Wiechert, Wolfgang; Kohlheyer, Dietrich

    2016-09-01

    Conventional propidium iodide (PI) staining requires the execution of multiple steps prior to analysis, potentially affecting assay results as well as cell vitality. In this study, this multistep analysis method has been transformed into a single-step, non-toxic, real-time method via live-cell imaging during perfusion with 0.1 μM PI inside a microfluidic cultivation device. Dynamic PI staining was an effective live/dead analytical tool and demonstrated consistent results for single-cell death initiated by direct or indirect triggers. Application of this method for the first time revealed the apparent antibiotic tolerance of wild-type Corynebacterium glutamicum cells, as indicated by the conversion of violet fluorogenic calcein acetoxymethyl ester (CvAM). Additional implementation of this method provided insight into the induced cell lysis of Escherichia coli cells expressing a lytic toxin-antitoxin module, providing evidence for non-lytic cell death and cell resistance to toxin production. Finally, our dynamic PI staining method distinguished necrotic-like and apoptotic-like cell death phenotypes in Saccharomyces cerevisiae among predisposed descendants of nutrient-deprived ancestor cells using PO-PRO-1 or green fluorogenic calcein acetoxymethyl ester (CgAM) as counterstains. The combination of single-cell cultivation, fluorescent time-lapse imaging, and PI perfusion facilitates spatiotemporally resolved observations that deliver new insights into the dynamics of cellular behaviour.

  10. Effects of ultraviolet-visible irradiation in the presence of melanin isolated from human black or red hair upon Ehrlich ascites carcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Menon, I.A.; Persad, S.; Ranadive, N.S.; Haberman, H.F.

    1983-07-01

    The present study is an attempt to investigate the possibility that ultraviolet irradiation in the presence of pheomelanin may be more harmful to cells than the irradiation in the presence of eumelanin. The effects of UV-visible irradiation upon Ehrlich ascites carcinoma cells in the presence of the melanin isolated from human black hair (eumelanin) or from red hair (pheomelanin) were investigated. Irradiation of these cells was found to produce cell lysis, as observed by leakage of 51Cr from labeled cells and intracellular lactic dehydrogenase from the cells and decrease in cell viability demonstrated by the trypan blue exclusion test. The three parameters were quantitatively parallel to one another under various experimental conditions, namely different periods of irradiation and irradiation in the presence of different concentrations of melanin. The above effects were more pronounced when the irradiation was carried out in the presence of melanin from red hair than in the presence of black-hair melanin. In the absence of either melanin, the irradiation did not produce any significant effect in cell viability or cell lysis. Irradiation of the cells in the presence of red-hair melanin also decreased the transplantability of these cells. These observations clearly show that irradiation of cells in the presence of pheomelanin could produce cytotoxic effects. The present experimental design may have application in the development of in vitro models for the study of UV radiation-induced cutaneous carcinogenesis. The reactions of pheomelanin may be related to the susceptibility of ''Celtic'' skin to UV radiation-induced skin damage and carcinogenesis.

  11. Simultaneous measurement of hormone release and secretagogue binding by individual pituitary cells

    International Nuclear Information System (INIS)

    Smith, P.F.; Neill, J.D.

    1987-01-01

    The quantitative relationship between receptor binding and hormone secretion at the single-cell level was investigated in the present study by combining a reverse hemolytic plaque assay for measurement of luteinizing hormone (LH) secretion from individual pituitary cells with an autoradiographic assay of 125 I-labeled gonadontropin-releasing hormone (GnRH) agonist binding to the same cells. In the plaque assay, LH secretion induces complement-mediated lysis of the LH-antibody-coated erythrocytes around the gonadotropes, resulting in areas of lysis (plaques). LH release from individual gonadotropes was quantified by comparing radioimmunoassayable LH release to hemolytic area in similarly treated cohort groups of cells; plaque area was linearly related to the amount of LH secreted. Receptor autoradiography was performed using 125 I-labeled GnRH-A (a superagonist analog of GnRH) both as the ligand and as the stimulant for LH release in the plaque assay. The grains appeared to represent specific and high-affinity receptors for GnRH because (i) no pituitary cells other than gonadotropes bound the labeled ligand and (ii) grain development was progressively inhibited by coincubation with increasing doses of unlabeled GnRH-A. The authors conclude that GnRH receptor number for any individual gonadotrope is a weak determinant of the amount of LH it can secrete; nevertheless, full occupancy of all its GnRH receptors is required for any gonadotrope to reach its full LH-secretory capacity. Apparently the levels of other factors comprising the steps along the secretory pathway determine the secretory capacity of an individual cell

  12. Development of tumor-reactive T cells after nonmyeloablative allogeneic hematopoietic stem cell transplant for chronic lymphocytic leukemia.

    Science.gov (United States)

    Nishida, Tetsuya; Hudecek, Michael; Kostic, Ana; Bleakley, Marie; Warren, Edus H; Maloney, David; Storb, Rainer; Riddell, Stanley R

    2009-07-15

    Allogeneic nonmyeloablative hematopoietic stem cell transplant (NM-HSCT) can result in durable remission of chronic lymphocytic leukemia (CLL). It is thought that the efficacy of NM-HSCT is mediated by recognition of tumor cells by T cells in the donor stem cell graft. We evaluated the development of CTLs specific for CLL after NM-HSCT to determine if their presence correlated with antitumor efficacy. Peripheral blood mononuclear cells obtained from 12 transplant recipients at intervals after NM-HSCT were stimulated in vitro with CLL cells. Polyclonal T-cell lines and CD8(+) T-cell clones were derived from these cultures and evaluated for lysis of donor and recipient target cells including CLL. The presence and specificity of responses was correlated with clinical outcomes. Eight of the 12 patients achieved remission or a major antitumor response and all 8 developed CD8(+) and CD4(+) T cells specific for antigens expressed by CLL. A clonal analysis of the CD8(+) T-cell response identified T cells specific for multiple minor histocompatibility (H) antigens expressed on CLL in six of the responding patients. A significant fraction of the CD8(+) T-cell response in some patients was also directed against nonshared tumor-specific antigens. By contrast, CLL-reactive T cells were not detected in the four patients who had persistent CLL after NM-HSCT, despite the development of graft-versus-host disease. The development of a diverse T-cell response specific for minor H and tumor-associated antigens expressed by CLL predicts an effective graft-versus-leukemia response after NM-HSCT.

  13. Single-Cell mRNA-Seq Using the Fluidigm C1 System and Integrated Fluidics Circuits.

    Science.gov (United States)

    Gong, Haibiao; Do, Devin; Ramakrishnan, Ramesh

    2018-01-01

    Single-cell mRNA-seq is a valuable tool to dissect expression profiles and to understand the regulatory network of genes. Microfluidics is well suited for single-cell analysis owing both to the small volume of the reaction chambers and easiness of automation. Here we describe the workflow of single-cell mRNA-seq using C1 IFC, which can isolate and process up to 96 cells. Both on-chip procedure (lysis, reverse transcription, and preamplification PCR) and off-chip sequencing library preparation protocols are described. The workflow generates full-length mRNA information, which is more valuable compared to 3' end counting method for many applications.

  14. Massively parallel whole genome amplification for single-cell sequencing using droplet microfluidics.

    Science.gov (United States)

    Hosokawa, Masahito; Nishikawa, Yohei; Kogawa, Masato; Takeyama, Haruko

    2017-07-12

    Massively parallel single-cell genome sequencing is required to further understand genetic diversities in complex biological systems. Whole genome amplification (WGA) is the first step for single-cell sequencing, but its throughput and accuracy are insufficient in conventional reaction platforms. Here, we introduce single droplet multiple displacement amplification (sd-MDA), a method that enables massively parallel amplification of single cell genomes while maintaining sequence accuracy and specificity. Tens of thousands of single cells are compartmentalized in millions of picoliter droplets and then subjected to lysis and WGA by passive droplet fusion in microfluidic channels. Because single cells are isolated in compartments, their genomes are amplified to saturation without contamination. This enables the high-throughput acquisition of contamination-free and cell specific sequence reads from single cells (21,000 single-cells/h), resulting in enhancement of the sequence data quality compared to conventional methods. This method allowed WGA of both single bacterial cells and human cancer cells. The obtained sequencing coverage rivals those of conventional techniques with superior sequence quality. In addition, we also demonstrate de novo assembly of uncultured soil bacteria and obtain draft genomes from single cell sequencing. This sd-MDA is promising for flexible and scalable use in single-cell sequencing.

  15. Culture of human cell lines by a pathogen-inactivated human platelet lysate.

    Science.gov (United States)

    Fazzina, R; Iudicone, P; Mariotti, A; Fioravanti, D; Procoli, A; Cicchetti, E; Scambia, G; Bonanno, G; Pierelli, L

    2016-08-01

    Alternatives to the use of fetal bovine serum (FBS) have been investigated to ensure xeno-free growth condition. In this study we evaluated the efficacy of human platelet lysate (PL) as a substitute of FBS for the in vitro culture of some human cell lines. PL was obtained by pools of pathogen inactivated human donor platelet (PLT) concentrates. Human leukemia cell lines (KG-1, K562, JURKAT, HL-60) and epithelial tumor cell lines (HeLa and MCF-7) were cultured with either FBS or PL. Changes in cell proliferation, viability, morphology, surface markers and cell cycle were evaluated for each cell line. Functional characteristics were analysed by drug sensitivity test and cytotoxicity assay. Our results demonstrated that PL can support growth and expansion of all cell lines, although the cells cultured in presence of PL experienced a less massive proliferation compared to those grown with FBS. We found a comparable percentage of viable specific marker-expressing cells in both conditions, confirming lineage fidelity in all cultures. Functionality assays showed that cells in both FBS- and PL-supported cultures maintained their normal responsiveness to adriamycin and NK cell-mediated lysis. Our findings indicate that PL is a feasible serum substitute for supporting growth and propagation of haematopoietic and epithelial cell lines with many advantages from a perspective of process standardization, ethicality and product safety.

  16. Engineering Cyanobacterial Cell Morphology for Enhanced Recovery and Processing of Biomass.

    Science.gov (United States)

    Jordan, Adam; Chandler, Jenna; MacCready, Joshua S; Huang, Jingcheng; Osteryoung, Katherine W; Ducat, Daniel C

    2017-05-01

    Cyanobacteria are emerging as alternative crop species for the production of fuels, chemicals, and biomass. Yet, the success of these microbes depends on the development of cost-effective technologies that permit scaled cultivation and cell harvesting. Here, we investigate the feasibility of engineering cell morphology to improve biomass recovery and decrease energetic costs associated with lysing cyanobacterial cells. Specifically, we modify the levels of Min system proteins in Synechococcus elongatus PCC 7942. The Min system has established functions in controlling cell division by regulating the assembly of FtsZ, a tubulin-like protein required for defining the bacterial division plane. We show that altering the expression of two FtsZ-regulatory proteins, MinC and Cdv3, enables control over cell morphology by disrupting FtsZ localization and cell division without preventing continued cell growth. By varying the expression of these proteins, we can tune the lengths of cyanobacterial cells across a broad dynamic range, anywhere from an ∼20% increased length (relative to the wild type) to near-millimeter lengths. Highly elongated cells exhibit increased rates of sedimentation under low centrifugal forces or by gravity-assisted settling. Furthermore, hyperelongated cells are also more susceptible to lysis through the application of mild physical stress. Collectively, these results demonstrate a novel approach toward decreasing harvesting and processing costs associated with mass cyanobacterial cultivation by altering morphology at the cellular level. IMPORTANCE We show that the cell length of a model cyanobacterial species can be programmed by rationally manipulating the expression of protein factors that suppress cell division. In some instances, we can increase the size of these cells to near-millimeter lengths with this approach. The resulting elongated cells have favorable properties with regard to cell harvesting and lysis. Furthermore, cells treated in this

  17. Contribution of the Staphylococcus aureus Atl AM and GL murein hydrolase activities in cell division, autolysis, and biofilm formation.

    Directory of Open Access Journals (Sweden)

    Jeffrey L Bose

    Full Text Available The most prominent murein hydrolase of Staphylococcus aureus, AtlA, is a bifunctional enzyme that undergoes proteolytic cleavage to yield two catalytically active proteins, an amidase (AM and a glucosaminidase (GL. Although the bifunctional nature of AtlA has long been recognized, most studies have focused on the combined functions of this protein in cell wall metabolism and biofilm development. In this study, we generated mutant derivatives of the clinical S. aureus isolate, UAMS-1, in which one or both of the AM and GL domains of AtlA have been deleted. Examination of these strains revealed that each mutant exhibited growth rates comparable to the parental strain, but showed clumping phenotypes and lysis profiles that were distinct from the parental strain and each other, suggesting distinct roles in cell wall metabolism. Given the known function of autolysis in the release of genomic DNA for use as a biofilm matrix molecule, we also tested the mutants in biofilm assays and found both AM and GL necessary for biofilm development. Furthermore, the use of enzymatically inactive point mutations revealed that both AM and GL must be catalytically active for S. aureus to form a biofilm. The results of this study provide insight into the relative contributions of AM and GL in S. aureus and demonstrate the contribution of Atl-mediated lysis in biofilm development.

  18. Contribution of the Staphylococcus aureus Atl AM and GL murein hydrolase activities in cell division, autolysis, and biofilm formation.

    Science.gov (United States)

    Bose, Jeffrey L; Lehman, McKenzie K; Fey, Paul D; Bayles, Kenneth W

    2012-01-01

    The most prominent murein hydrolase of Staphylococcus aureus, AtlA, is a bifunctional enzyme that undergoes proteolytic cleavage to yield two catalytically active proteins, an amidase (AM) and a glucosaminidase (GL). Although the bifunctional nature of AtlA has long been recognized, most studies have focused on the combined functions of this protein in cell wall metabolism and biofilm development. In this study, we generated mutant derivatives of the clinical S. aureus isolate, UAMS-1, in which one or both of the AM and GL domains of AtlA have been deleted. Examination of these strains revealed that each mutant exhibited growth rates comparable to the parental strain, but showed clumping phenotypes and lysis profiles that were distinct from the parental strain and each other, suggesting distinct roles in cell wall metabolism. Given the known function of autolysis in the release of genomic DNA for use as a biofilm matrix molecule, we also tested the mutants in biofilm assays and found both AM and GL necessary for biofilm development. Furthermore, the use of enzymatically inactive point mutations revealed that both AM and GL must be catalytically active for S. aureus to form a biofilm. The results of this study provide insight into the relative contributions of AM and GL in S. aureus and demonstrate the contribution of Atl-mediated lysis in biofilm development.

  19. Xenodiagnostico, hemocultura e teste de lise mediada pelo complemento, como critérios de seleção de pacientes chagásicos crônicos para quimioterapia Xenodiagnosis, hemoculture and complement mediated lysis tests as criteria for selection of chronic chagasic patients for chemotherapy

    Directory of Open Access Journals (Sweden)

    Vera Lúcia Pereira

    1989-10-01

    Full Text Available O tratamento etiológico da doença de Chagas é iniciado geralmente apenas quando se dispõe de um diagnóstico parasitológico positivo. Na tentativa de aumentar o número de candidatos assim selecionados para o tratamento específico, estudamos 36 pacientes chagásicos crônicos associando o xenodiagnóstico, a hemocultura e o teste de lise mediada pelo complemento, em duas séries sucessivas, intercaladas de um mínimo de 60 dias. A sensibilidade do xenodiagnóstico e da hemocultura foi respectivamente de 30,5% e de 8,3% na primeira série e de 36,1% e de 19,4% nas duas séries. Foram positivos, em pelo menos uma das duas provas, 17 (47,2% dos pacientes. Destes, entretanto, somente 9 (53,0% mostraram teste de lise constantemente positivo enquanto que em 5 (29,4% o teste foi negativo e 3 (17,6% apresentaram resultados ora positivos, ora negativos. Nos pacientes com provas parasitológicas negativas, o teste de lise foi positivo em 4 (15,8%, negativo em 9 (47,4% e discordante em 6 (31,5%. Assim, o teste de lise mediada pelo complemento não se constitue em bom método de triagem de candidatos ao tratamento. Apesar da baixa sensibilidade, as provas parasitológicas ainda constituem o instrumento mais seguro para o clínico.Normally specific treatment of chronic Chagas' disease begins only after a positive parasitological diagnosis has been established. Xenodiagnosis, hemoculture and complement mediated lysis were associated, and repeated, as an attempt to increase the number of selected candidates for specific treatment. Thirty six chronic chagasic patients were submitted to two series of the above tests, with a minimal interval of 60 days. In the first series of tests sensitivity of xenodiagnosis and hemoculture were 30.5% and 8.3% respectively. Processing of a second sample increased sensitivity to 36.1% (xenodiagnosis and 19.4% (hemoculture; 47.2% were shown to be positive by at least one of these tests. From the positive cases, 29.4% were

  20. Constitutively polarized granules prime KHYG-1 NK cells.

    Science.gov (United States)

    Suck, Garnet; Branch, Donald R; Aravena, Paola; Mathieson, Mark; Helke, Simone; Keating, Armand

    2006-09-01

    The major mechanism for NK cell lysis of tumor cells is granule-mediated cytotoxicity. Polarization of granules is a prelude to the release of their cytotoxic contents in response to target-cell binding. We describe the novel observation of constitutive granule polarization in the cytotoxic NK cell line, KHYG-1. Continuous degranulation of KHYG-1 cells, however, does not occur and still requires target-cell contact. Disruption of microtubules with colcemid is sufficient to disperse the granules in KHYG-1 and significantly decreases cytotoxicity. A similar effect is not obtained by inhibiting extracellular signal-related kinase 2 (ERK2), the most distal kinase investigated in the cytolytic pathway. Disruption of microtubules significantly down-regulates activation receptors, NKp44 and NKG2D, implicating them as potential microtubule-trafficking receptors. Such changes in upstream receptor expression may have caused deactivation of ERK2, since NKG2D cross-linking also leads to receptor down-regulation and diminished ERK phosphorylation. Thus, a functional role for NKG2D in KHYG-1 cytotoxicity is demonstrated. Moreover, the novel primed state may contribute to the high cytotoxicity exhibited by KHYG-1.

  1. Rotavirus RRV associates with lipid membrane microdomains during cell entry

    International Nuclear Information System (INIS)

    Isa, Pavel; Realpe, Mauricio; Romero, Pedro; Lopez, Susana; Arias, Carlos F.

    2004-01-01

    Rotavirus cell entry is a multistep process, not completely understood, which requires at least four interactions between the virus and cell surface molecules. In this work, we investigated the role of the sphingolipid- and cholesterol-enriched lipid microdomains (rafts) in the entry of rotavirus strain RRV to MA104 cells. We found that ganglioside GM1, integrin subunits α2 and β3, and the heat shock cognate protein 70 (hsc70), all of which have been implicated as rotavirus receptors, are associated with TX-100 and Lubrol WX detergent-resistant membranes (DRMs). Integrin subunits α2 and β3 were found to be particularly enriched in DRMs resistant to lysis by Lubrol WX. When purified RRV particles were incubated with cells at 4 deg. C, about 10% of the total infectious virus was found associated with DRMs, and the DRM-associated virus increased to 37% in Lubrol-resistant membrane domains after 60-min incubation at 37 deg. C. The virus was excluded from DRMs if the cells were treated with methyl-β-cyclodextrin (MβCD). Immunoblot analysis of the viral proteins showed that the virus surface proteins became enriched in DRMs upon incubation at 37 deg. C, being almost exclusively localized in Lubrol-resistant DRMs after 60 min. These data suggest that detergent-resistant membrane domains play an important role in the cell entry of rotaviruses, which could provide a platform to facilitate the efficient interaction of the rotavirus receptors with the virus particle

  2. Persistence of Coxsackievirus B4 in pancreatic ductal-like cells results in cellular and viral changes.

    Science.gov (United States)

    Alidjinou, E K; Engelmann, I; Bossu, J; Villenet, C; Figeac, M; Romond, M-B; Sané, F; Hober, D

    2017-10-03

    Although known as cytolytic viruses, group B coxackieviruses (CVB) are able to establish a persistent infection in vitro and in vivo. Viral persistence has been reported as a key mechanism in the pathogenesis of CVB-associated chronic diseases such as type 1 diabetes (T1D). The impact of CVB4 persistence on human pancreas ductal-like cells was investigated. A persistent CVB4 infection was established in ductal-like cells. PDX-1 expression, resistance to CVB4-induced lysis and CAR expression were evaluated. The profile of cellular microRNAs (miRNAs) was investigated through miRNA-sequencing. Viral phenotypic changes were examined, and genomic modifications were assessed by sequencing of the viral genome. The CVB4 persistence in ductal-like cells was productive, with continuous release of infectious particles. Persistently infected cells displayed a resistance to CVB4-induced lysis upon superinfection and expression of PDX-1 and CAR was decreased. These changes were maintained even after virus clearance. The patterns of cellular miRNA expression in mock-infected and in CVB4-persistently infected ductal-like cells were clearly different. The persistent infection-derived virus (PIDV) was still able to induce cytopathic effect but its plaques were smaller than the parental virus. Several mutations appeared in various PIDV genome regions, but amino acid substitutions did not affect the predicted site of interaction with CAR. Cellular and viral changes occur during persistent infection of human pancreas ductal-like cells with CVB4. The persistence of cellular changes even after virus clearance supports the hypothesis of a long-lasting impact of persistent CVB infection on the cells.

  3. Optimization of dendritic cell loading with tumor cell lysates for cancer immunotherapy.

    Science.gov (United States)

    Hatfield, Paul; Merrick, Alison E; West, Emma; O'Donnell, Dearbhaile; Selby, Peter; Vile, Richard; Melcher, Alan A

    2008-09-01

    The immune response to cancer is critically determined by the way in which tumor cells die. As necrotic, stress-associated death can be associated with activation of antitumor immunity, whole tumor cell antigen loading strategies for dendritic cell (DC)-based vaccination have commonly used freeze-thaw "necrotic" lysates as an immunogenic source of tumor-associated antigens. In this study, the effect of such lysates on the ability of DCs to mature in response to well-established maturation stimuli was examined, and methods to enhance lysate-induced DC activation explored. Freeze-thaw lysates were prepared from murine tumor cell lines and their effects on bone marrow-derived DC maturation and function examined. Unmodified freeze-thaw tumor cell lysates inhibited the toll-like receptor-induced maturation and function of bone marrow-derived DCs, preventing up-regulation of CD40, CD86, and major histocompatibility complex class II, and reducing secretion of inflammatory cytokines [interleukin (IL)-12 p70, tumor necrosis factor-alpha, and IL-6]. Although IL-10 secretion was increased by lysate-pulsed DCs, this was not responsible for the observed suppression of IL-12. Although activation of the nuclear factor-kappaB pathway remained intact, the kinase activity of phosphorylated p38 mitogen-activated protein kinase was inhibited in lysate-pulsed DCs. Lysate-induced DC suppression was partially reversed in vitro by induction of tumor cell stress before lysis, and only DCs loaded with stressed lysates afforded protection against tumor challenge in vivo. These data suggest that ex vivo freeze-thaw of tumor cells does not effectively mimic in vivo immunogenic necrosis, and advocates careful characterization and optimization of tumor cell-derived vaccine sources for cancer immunotherapy.

  4. Monitoring and Management of Toxicities of Novel B Cell Signaling Agents.

    Science.gov (United States)

    Rhodes, Joanna; Mato, Anthony; Sharman, Jeff P

    2018-04-11

    B cell signaling agents, including ibrutinib, idelalisib, and the BCL-2 inhibitor venetoclax have become an integral part of therapy for patients with non-Hodgkin's lymphomas. The toxicity profiles of these medications is distinct from chemoimmunotherapy. Here, we will review the mechanism of action of these drugs, their efficacy, and toxicity management. Ibrutinib use is associated with increased risk of atrial fibrillation and bleeding which can be managed using dose interruptions and modifications. Patients on idelalisib require close clinical and frequent laboratory monitoring, particularly of liver function tests to ensure there are no serious adverse events. Monitoring for infections is important in patients on both idelalisib and ibrutinib. Venetoclax requires close clinical and laboratory monitoring to prevent significant tumor lysis. Targeted B cell receptor therapies each have unique side effect profiles which require careful clinical monitoring. As we continue to use these therapies, optimal management strategies will continue to be elucidated.

  5. Histochemical applications of x-ray microanalysis: the simultaneous assessment of mitosis and cell death

    International Nuclear Information System (INIS)

    Bowen, I.D.; Lewis, G.H.

    1980-01-01

    The principles of x-ray microanalytical histochemistry are reviewed. The use of labelling and precipitation techniques are examined, and particular attention is paid to the localization of enzymatic activity. A new method is described for the simultaneous assessment of mitosis as represented by the incorporation of ( 3 H) thymidine, and cell death as represented by the localization of free acid phosphatase, in the same tissue section. The thymidine incorporation is demonstrated by the appearance of topographically and microanalytically detectable silver grains in an overlying emulsion and the cell lysis associated acid phosphatase activity is detected optically and microanalytically by means of a bromine-rich azo dye deposited as a result of coupling naphthol AS BI, enzymatically released from naphthyl AS BI phosphoric acid, with diazotized 2,5-dibromoaniline

  6. Lactose/whey utilization and ethanol production by transformed Saccharomyces cerevisiae cells.

    Science.gov (United States)

    Porro, D; Martegani, E; Ranzi, B M; Alberghina, L

    1992-04-05

    Strains of Saccharomyces cerevisiae transformed with a multicopy expression vector bearing both the Escherichia coli beta-galactosidase gene under the control of the upstream activating sequence of the GAL1-10 genes and the GAL4 activator gene release part of beta-galactosidase in the growth medium. This release is due to cell lysis of the older mother cells; the enzyme maintains its activity in buffered growth media. Fermentation studies with transformed yeast strains showed that the release of beta-galactosidase allowed an efficient growth on buffered media containing lactose as carbon source as well as on whey-based media. The transformed strains utilized up to 95% of the lactose and a high growth yield was obtained in rich media. High productions of ethanol were also observed in stationary phase after growth in lactose minimal media.

  7. A novel cell autolysis system for cost-competitive downstream processing.

    Science.gov (United States)

    Hajnal, Ivan; Chen, Xiangbin; Chen, Guo-Qiang

    2016-11-01

    The industrial production of low value-added biological products poses significant challenges due to cost pressures. In recent years, it has been argued that synthetic biology approaches will lead to breakthroughs that eliminate price bottlenecks for the production of a wide range of biological products including bioplastics and biofuels. One significant bottleneck lies in the necessity to break the tough cell walls of microbes in order to release intracellular products. We here report the implementation of the first synthetic biology standard part based on the lambda phage SRRz genes and a synthetic ribosome binding site (RBS) that works in Escherichia coli and Halomonas campaniensis, which enables the producer strains to induce lysis after the addition of small amounts (1-5 %) of solvents or to spontaneously lyse during the stresses of downstream processing, and thus has the potential to eliminate the mechanical cell disruption step as both an efficiency bottleneck and a significant capex barrier when implementing downstream bioprocesses.

  8. Cell wall elongation mode in Gram-negative bacteria is determined by peptidoglycan architecture.

    Science.gov (United States)

    Turner, Robert D; Hurd, Alexander F; Cadby, Ashley; Hobbs, Jamie K; Foster, Simon J

    2013-01-01

    Cellular integrity and morphology of most bacteria is maintained by cell wall peptidoglycan, the target of antibiotics essential in modern healthcare. It consists of glycan strands, cross-linked by peptides, whose arrangement determines cell shape, prevents lysis due to turgor pressure and yet remains dynamic to allow insertion of new material, and hence growth. The cellular architecture and insertion pattern of peptidoglycan have remained elusive. Here we determine the peptidoglycan architecture and dynamics during growth in rod-shaped Gram-negative bacteria. Peptidoglycan is made up of circumferentially oriented bands of material interspersed with a more porous network. Super-resolution fluorescence microscopy reveals an unexpected discontinuous, patchy synthesis pattern. We present a consolidated model of growth via architecture-regulated insertion, where we propose only the more porous regions of the peptidoglycan network that are permissive for synthesis.

  9. Murine neonatal spleen contains natural T and non-T suppressor cells capable of inhibiting adult alloreactive and newborn autoreactive T-cell proliferation.

    Science.gov (United States)

    Hooper, D C; Hoskin, D W; Gronvik, K O; Murgita, R A

    1986-05-01

    The spleen of neonatal mice is known to be a rich source of cells capable of suppressing a variety of immune functions of adult lymphocytes in vitro. From such observations has emerged the concept that the gradual development in ability to express immune functions after birth is due in part to the parallel normal physiological decay of naturally occurring regulatory suppressor cells. There is, however, some confusion in the literature as to the exact nature of the newborn of the newborn inhibitory cell type(s). In contrast to most previous reports which detect only a single type of neonatal suppressor cell, usually a T cell, we show here that newborn spleen harbors both T and non-T inhibitory cells. Both types of suppressor cells could be shown to suppress the proliferative response of adult spleen to alloantigens as well as newborn T cells reacting against self-Ia antigen in the autologous mixed lymphocyte reaction (AMLR). Newborn suppressor T cells were characterized as being non-adherent to Ig-anti-Ig affinity columns, soybean agglutinin receptor negative (SBA-), and susceptible to lysis by anti-T-cell specific antiserum plus complement. Non-T suppressor cells were identified as non-phagocytic, SBA receptor positive (SBA+), and resistant to cytotoxic treatment with anti-T-cell antibodies and complement. The apparent controversy surrounding previous reports as to the T versus non-T nature of newborn suppressor cells can be reconciled by the present observation that both types of inhibitory cells coexist in the spleen. Furthermore, the demonstration that newborn suppressor cells can effectively regulate T-cell proliferative activity mediated by other newborn cells provides more direct support for the contention that such inhibitory cells play a physiological role in controlling immune responsiveness during early ontogeny.

  10. Use of an adaptable cell culture kit for performing lymphocyte and monocyte cell cultures in microgravity

    Science.gov (United States)

    Hatton, J. P.; Lewis, M. L.; Roquefeuil, S. B.; Chaput, D.; Cazenave, J. P.; Schmitt, D. A.

    1998-01-01

    The results of experiments performed in recent years on board facilities such as the Space Shuttle/Spacelab have demonstrated that many cell systems, ranging from simple bacteria to mammalian cells, are sensitive to the microgravity environment, suggesting gravity affects fundamental cellular processes. However, performing well-controlled experiments aboard spacecraft offers unique challenges to the cell biologist. Although systems such as the European 'Biorack' provide generic experiment facilities including an incubator, on-board 1-g reference centrifuge, and contained area for manipulations, the experimenter must still establish a system for performing cell culture experiments that is compatible with the constraints of spaceflight. Two different cell culture kits developed by the French Space Agency, CNES, were recently used to perform a series of experiments during four flights of the 'Biorack' facility aboard the Space Shuttle. The first unit, Generic Cell Activation Kit 1 (GCAK-1), contains six separate culture units per cassette, each consisting of a culture chamber, activator chamber, filtration system (permitting separation of cells from supernatant in-flight), injection port, and supernatant collection chamber. The second unit (GCAK-2) also contains six separate culture units, including a culture, activator, and fixation chambers. Both hardware units permit relatively complex cell culture manipulations without extensive use of spacecraft resources (crew time, volume, mass, power), or the need for excessive safety measures. Possible operations include stimulation of cultures with activators, separation of cells from supernatant, fixation/lysis, manipulation of radiolabelled reagents, and medium exchange. Investigations performed aboard the Space Shuttle in six different experiments used Jurkat, purified T-cells or U937 cells, the results of which are reported separately. We report here the behaviour of Jurkat and U937 cells in the GCAK hardware in ground

  11. Neuroblastoma Cell Lines Are Refractory to Genotoxic Drug-Mediated Induction of Ligands for NK Cell-Activating Receptors

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    Irene Veneziani

    2018-01-01

    Full Text Available Neuroblastoma (NB, the most common extracranial solid tumor of childhood, causes death in almost 15% of children affected by cancer. Treatment of neuroblastoma is based on the combination of chemotherapy with other therapeutic interventions such as surgery, radiotherapy, use of differentiating agents, and immunotherapy. In particular, adoptive NK cell transfer is a new immune-therapeutic approach whose efficacy may be boosted by several anticancer agents able to induce the expression of ligands for NK cell-activating receptors, thus rendering cancer cells more susceptible to NK cell-mediated lysis. Here, we show that chemotherapeutic drugs commonly used for the treatment of NB such as cisplatin, topotecan, irinotecan, and etoposide are unable to induce the expression of activating ligands in a panel of NB cell lines. Consistently, cisplatin-treated NB cell lines were not more susceptible to NK cells than untreated cells. The refractoriness of NB cell lines to these drugs has been partially associated with the abnormal status of genes for ATM, ATR, Chk1, and Chk2, the major transducers of the DNA damage response (DDR, triggered by several anticancer agents and promoting different antitumor mechanisms including the expression of ligands for NK cell-activating receptors. Moreover, both the impaired production of reactive oxygen species (ROS in some NB cell lines and the transient p53 stabilization in response to our genotoxic drugs under our experimental conditions could contribute to inefficient induction of activating ligands. These data suggest that further investigations, exploiting molecular strategies aimed to potentiate the NK cell-mediated immunotherapy of NB, are warranted.

  12. Neuroblastoma Cell Lines Are Refractory to Genotoxic Drug-Mediated Induction of Ligands for NK Cell-Activating Receptors

    Science.gov (United States)

    Veneziani, Irene; Brandetti, Elisa; Ognibene, Marzia; Pezzolo, Annalisa; Pistoia, Vito

    2018-01-01

    Neuroblastoma (NB), the most common extracranial solid tumor of childhood, causes death in almost 15% of children affected by cancer. Treatment of neuroblastoma is based on the combination of chemotherapy with other therapeutic interventions such as surgery, radiotherapy, use of differentiating agents, and immunotherapy. In particular, adoptive NK cell transfer is a new immune-therapeutic approach whose efficacy may be boosted by several anticancer agents able to induce the expression of ligands for NK cell-activating receptors, thus rendering cancer cells more susceptible to NK cell-mediated lysis. Here, we show that chemotherapeutic drugs commonly used for the treatment of NB such as cisplatin, topotecan, irinotecan, and etoposide are unable to induce the expression of activating ligands in a panel of NB cell lines. Consistently, cisplatin-treated NB cell lines were not more susceptible to NK cells than untreated cells. The refractoriness of NB cell lines to these drugs has been partially associated with the abnormal status of genes for ATM, ATR, Chk1, and Chk2, the major transducers of the DNA damage response (DDR), triggered by several anticancer agents and promoting different antitumor mechanisms including the expression of ligands for NK cell-activating receptors. Moreover, both the impaired production of reactive oxygen species (ROS) in some NB cell lines and the transient p53 stabilization in response to our genotoxic drugs under our experimental conditions could contribute to inefficient induction of activating ligands. These data suggest that further investigations, exploiting molecular strategies aimed to potentiate the NK cell-mediated immunotherapy of NB, are warranted. PMID:29805983

  13. Thiolated chitosan nanoparticles: transfection study in the Caco-2 differentiated cell culture

    International Nuclear Information System (INIS)

    Martien, Ronny; Loretz, Brigitta; Sandbichler, Adolf Michael; Schnuerch, Andreas Bernkop

    2008-01-01

    The aim of this study was to monitor the expression of secreted protein in differentiated Caco-2 cells after transfection with nanoparticles, in order to improve gene delivery. Based on unmodified chitosan and thiolated chitosan conjugates, nanoparticles with the gene reporter pSEAP (recombinant Secreted Alkaline Phosphatase) were generated at pH 4.0. Transfection studies of thiolated chitosan in Caco-2 cells during the exponential growth phase and differentiation growth phase of the cells led to a 5.0-fold and 2.0-fold increase in protein expression when compared to unmodified chitosan nanoparticles. The mean particle size for both unmodified chitosan and cross-linked thiolated chitosan nanoparticles is 212.2 ± 86 and 113.6 ± 40 nm, respectively. The zeta potential of nanoparticles was determined to be 7.9 ± 0.38 mV for unmodified chitosan nanoparticles and 4.3 ± 0.74 mV for cross-linked thiolated chitosan nanoparticles. Red blood cell lysis evaluation was used to evaluate the membrane damaging properties of unmodified and thiolated chitosan nanoparticles and led to 4.61 ± 0.36% and 2.29 ± 0.25% lysis, respectively. Additionally, cross-linked thiolated chitosan nanoparticles were found to exhibit higher stability toward degradation in gastric juices. Furthermore the reversible effect of thiolated chitosan on barrier properties was monitored by measuring the transepithelial electrical resistance (TEER) and is supported by immunohistochemical staining for the tight junction protein claudin. According to these results cross-linked thiolated chitosan nanoparticles have the potential to be used as a non-viral vector system for gene therapy

  14. Dual Functions of Natural Killer Cells in Selection and Differentiation of Stem Cells; Role in Regulation of Inflammation and Regeneration of Tissues

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    Anahid Jewett, Yan-Gao Man, Han-Ching Tseng

    2013-01-01

    Full Text Available Accumulated evidence from our laboratory indicates that conditioned or anergized NK cells have the ability to induce resistance of healthy stem cells and transformed cancer stem cells through both secreted factors and direct cell-cell contact by inducing differentiation. Cytotoxic function of NK cells is suppressed in the tumor microenvironment by a number of distinct effectors and their secreted factors. Furthermore, decreased peripheral blood NK cell function has been documented in many cancer patients. We have previously shown that NK cells mediate significant cytotoxicity against primary oral squamous carcinoma stem cells (OSCSCs as compared to their more differentiated oral squamous carcinoma cells (OSCCs. In addition, human embryonic stem cells (hESCs, human mesenchymal stem cells (hMSCs, human dental pulp stem cells (hDPSCs and induced human pluripotent stem cells (hiPSCs were all significantly more susceptible to NK cell mediated cytotoxicity than their differentiated counterparts or parental cells from which they were derived. We have also reported that inhibition of differentiation or reversion of cells to a less-differentiated phenotype by blocking NFκB or gene deletion of COX2 significantly augmented NK cell function. Furthermore, the induction of resistance of the stem cells to NK cell mediated cytotoxicity and their subsequent differentiation is amplified when either the stem cells or the NK cells were cultured in the presence of monocytes. Therefore, we propose that the two stages of NK cell maturation namely CD16+CD56dimCD69- NK cells are important for the lysis of stem cells or poorly differentiated cells whereas the CD16dim/-CD56dim/+CD69+NK cells are important for differentiation and eventual regeneration of the tissues and the resolution of inflammation, thus functionally serving as regulatory NK cells (NKreg. CD16 receptor on the NK cells were found to be the receptor with significant potential to induce NK cell anergy

  15. Bioinformatics approaches to single-cell analysis in developmental biology.

    Science.gov (United States)

    Yalcin, Dicle; Hakguder, Zeynep M; Otu, Hasan H

    2016-03-01

    Individual cells within the same population show various degrees of heterogeneity, which may be better handled with single-cell analysis to address biological and clinical questions. Single-cell analysis is especially important in developmental biology as subtle spatial and temporal differences in cells have significant associations with cell fate decisions during differentiation and with the description of a particular state of a cell exhibiting an aberrant phenotype. Biotechnological advances, especially in the area of microfluidics, have led to a robust, massively parallel and multi-dimensional capturing, sorting, and lysis of single-cells and amplification of related macromolecules, which have enabled the use of imaging and omics techniques on single cells. There have been improvements in computational single-cell image analysis in developmental biology regarding feature extraction, segmentation, image enhancement and machine learning, handling limitations of optical resolution to gain new perspectives from the raw microscopy images. Omics approaches, such as transcriptomics, genomics and epigenomics, targeting gene and small RNA expression, single nucleotide and structural variations and methylation and histone modifications, rely heavily on high-throughput sequencing technologies. Although there are well-established bioinformatics methods for analysis of sequence data, there are limited bioinformatics approaches which address experimental design, sample size considerations, amplification bias, normalization, differential expression, coverage, clustering and classification issues, specifically applied at the single-cell level. In this review, we summarize biological and technological advancements, discuss challenges faced in the aforementioned data acquisition and analysis issues and present future prospects for application of single-cell analyses to developmental biology. © The Author 2015. Published by Oxford University Press on behalf of the European

  16. Mesenchymal stromal cells engage complement and complement receptor bearing innate effector cells to modulate immune responses.

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    Guido Moll

    Full Text Available Infusion of human third-party mesenchymal stromal cells (MSCs appears to be a promising therapy for acute graft-versus-host disease (aGvHD. To date, little is known about how MSCs interact with the body's innate immune system after clinical infusion. This study shows, that exposure of MSCs to blood type ABO-matched human blood activates the complement system, which triggers complement-mediated lymphoid and myeloid effector cell activation in blood. We found deposition of complement component C3-derived fragments iC3b and C3dg on MSCs and fluid-phase generation of the chemotactic anaphylatoxins C3a and C5a. MSCs bound low amounts of immunoglobulins and lacked expression of complement regulatory proteins MCP (CD46 and DAF (CD55, but were protected from complement lysis via expression of protectin (CD59. Cell-surface-opsonization and anaphylatoxin-formation triggered complement receptor 3 (CD11b/CD18-mediated effector cell activation in blood. The complement-activating properties of individual MSCs were furthermore correlated with their potency to inhibit PBMC-proliferation in vitro, and both effector cell activation and the immunosuppressive effect could be blocked either by using complement inhibitor Compstatin or by depletion of CD14/CD11b-high myeloid effector cells from mixed lymphocyte reactions. Our study demonstrates for the first time a major role of the complement system in governing the immunomodulatory activity of MSCs and elucidates how complement activation mediates the interaction with other immune cells.

  17. Technical aspects and recommendations for single-cell qPCR.

    Science.gov (United States)

    Ståhlberg, Anders; Kubista, Mikael

    2018-02-01

    Single cells are basic physiological and biological units that can function individually as well as in groups in tissues and organs. It is central to identify, characterize and profile single cells at molecular level to be able to distinguish different kinds, to understand their functions and determine how they interact with each other. During the last decade several technologies for single-cell profiling have been developed and used in various applications, revealing many novel findings. Quantitative PCR (qPCR) is one of the most developed methods for single-cell profiling that can be used to interrogate several analytes, including DNA, RNA and protein. Single-cell qPCR has the potential to become routine methodology but the technique is still challenging, as it involves several experimental steps and few molecules are handled. Here, we discuss technical aspects and provide recommendation for single-cell qPCR analysis. The workflow includes experimental design, sample preparation, single-cell collection, direct lysis, reverse transcription, preamplification, qPCR and data analysis. Detailed reporting and sharing of experimental details and data will promote further development and make validation studies possible. Efforts aiming to standardize single-cell qPCR open up means to move single-cell analysis from specialized research settings to standard research laboratories. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Interaction and modulation of two antagonistic cell wall enzymes of mycobacteria.

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    Erik C Hett

    2010-07-01

    Full Text Available Bacterial cell growth and division require coordinated cell wall hydrolysis and synthesis, allowing for the removal and expansion of cell wall material. Without proper coordination, unchecked hydrolysis can result in cell lysis. How these opposing activities are simultaneously regulated is poorly understood. In Mycobacterium tuberculosis, the resuscitation-promoting factor B (RpfB, a lytic transglycosylase, interacts and synergizes with Rpf-interacting protein A (RipA, an endopeptidase, to hydrolyze peptidoglycan. However, it remains unclear what governs this synergy and how it is coordinated with cell wall synthesis. Here we identify the bifunctional peptidoglycan-synthesizing enzyme, penicillin binding protein 1 (PBP1, as a RipA-interacting protein. PBP1, like RipA, localizes both at the poles and septa of dividing cells. Depletion of the ponA1 gene, encoding PBP1 in M. smegmatis, results in a severe growth defect and abnormally shaped cells, indicating that PBP1 is necessary for viability and cell wall stability. Finally, PBP1 inhibits the synergistic hydrolysis of peptidoglycan by the RipA-RpfB complex in vitro. These data reveal a post-translational mechanism for regulating cell wall hydrolysis and synthesis through protein-protein interactions between enzymes with antagonistic functions.

  19. Epithelial cells as alternative human biomatrices for comet assay.

    Science.gov (United States)

    Rojas, Emilio; Lorenzo, Yolanda; Haug, Kristiane; Nicolaissen, Bjørn; Valverde, Mahara

    2014-01-01

    The comet assay is a valuable experimental tool aimed at mapping DNA damage in human cells in vivo for environmental and occupational monitoring, as well as for therapeutic purposes, such as storage prior to transplant, during tissue engineering, and in experimental ex vivo assays. Furthermore, due to its great versatility, the comet assay allows to explore the use of alternative cell types to assess DNA damage, such as epithelial cells. Epithelial cells, as specialized components of many organs, have the potential to serve as biomatrices that can be used to evaluate genotoxicity and may also serve as early effect biomarkers. Furthermore, 80% of solid cancers are of epithelial origin, which points to the importance of studying DNA damage in these tissues. Indeed, studies including comet assay in epithelial cells have either clear clinical applications (lens and corneal epithelial cells) or examine genotoxicity within human biomonitoring and in vitro studies. We here review improvements in determining DNA damage using the comet assay by employing lens, corneal, tear duct, buccal, and nasal epithelial cells. For some of these tissues invasive sampling procedures are needed. Desquamated epithelial cells must be obtained and dissociated prior to examination using the comet assay, and such procedures may induce varying amounts of DNA damage. Buccal epithelial cells require lysis enriched with proteinase K to obtain free nucleosomes. Over a 30 year period, the comet assay in epithelial cells has been little employed, however its use indicates that it could be an extraordinary tool not only for risk assessment, but also for diagnosis, prognosis of treatments and diseases.

  20. Blockade of maitotoxin-induced oncotic cell death reveals zeiosis

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    Schilling William P

    2002-01-01

    Full Text Available Abstract Background Maitotoxin (MTX initiates cell death by sequentially activating 1 Ca2+ influx via non-selective cation channels, 2 uptake of vital dyes via formation of large pores, and 3 release of lactate dehydrogenase, an indication of cell lysis. MTX also causes formation of membrane blebs, which dramatically dilate during the cytolysis phase. To determine the role of phospholipase C (PLC in the cell death cascade, U73122, a specific inhibitor of PLC, and U73343, an inactive analog, were examined on MTX-induced responses in bovine aortic endothelial cells. Results Addition of either U73122 or U73343, prior to MTX, produced a concentration-dependent inhibition of the cell death cascade (IC50 ≈ 1.9 and 0.66 μM, respectively suggesting that the effect of these agents was independent of PLC. Addition of U73343 shortly after MTX, prevented or attenuated the effects of the toxin, but addition at later times had little or no effect. Time-lapse videomicroscopy showed that U73343 dramatically altered the blebbing profile of MTX-treated cells. Specifically, U73343 blocked bleb dilation and converted the initial blebbing event into "zeiosis", a type of membrane blebbing commonly associated with apoptosis. Cells challenged with MTX and rescued by subsequent addition of U73343, showed enhanced caspase-3 activity 48 hr after the initial insult, consistent with activation of the apoptotic program. Conclusions Within minutes of MTX addition, endothelial cells die by oncosis. Rescue by addition of U73343 shortly after MTX showed that a small percentage of cells are destined to die by oncosis, but that a larger percentage survive; cells that survive the initial insult exhibit zeiosis and may ultimately die by apoptotic mechanisms.

  1. Rapid method for detecting base damage in DNA of mammalian cells: assay of U. V. -induced pyrimidine dimers in human cells

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, P E [Hammersmith Hospital, London (UK). M.R.C. Cyclotron Unit; Jansson, G; Ahnstroem, G

    1978-11-01

    Simple and rapid techniques are described for the detection of pyrimidine dimers in DNA. Human cells derived from embryonic lung tissue were UV-irradiated and subjected to either an osmotic shock procedure or detergent lysis, then treated with UV-endonuclease from Micrococcus luteus and the DNA partially denatured by treatment with weak alkali. Brief sonication reduced the molecular weight of the DNA, and the single- and double-stranded DNA could then be separated by hydroxylapatite chromatography. Approximately 40% of the expected number of pyrimidine dimers were detected by the enzyme treatment technique. The mean value of numbers of strand breaks per 10/sup 9/ dalton per J/m/sup 2/ was approximately 50% of the expected value. The method has advantages of speed and reproducibility and a large reduction in the quantities of materials used, particularly at the scintillation-counting stage.

  2. iNKT cell cytotoxic responses control T-lymphoma growth in vitro and in vivo

    Science.gov (United States)

    Bassiri, Hamid; Das, Rupali; Guan, Peng; Barrett, David M.; Brennan, Patrick J.; Banerjee, Pinaki P.; Wiener, Susan J.; Orange, Jordan S.; Brenner, Michael B.; Grupp, Stephan A.; Nichols, Kim E.

    2013-01-01

    Invariant natural killer T (iNKT) cells comprise a lineage of CD1d-restricted glycolipid-reactive T lymphocytes with important roles in host immunity to cancer. iNKT cells indirectly participate in antitumor responses by inducing dendritic cell maturation and producing cytokines that promote tumor clearance by CD8+ T and NK cells. Although iNKT cells thereby act as potent cellular adjuvants, it is less clear whether they directly control the growth of tumors. To gain insights into the direct contribution of iNKT cells to tumor immune surveillance, we developed in vitro and in vivo systems to selectively examine the antitumor activity of iNKT cells in the absence of other cytolytic effectors. Using the EL4 T-lymphoma cell line as a model, we find that iNKT cells exert robust and specific lysis of tumor cells in vitro in a manner that is differentially-induced by iNKT cell agonists of varying TCR affinities, such as OCH, α-galactosyl ceramide and PBS44. In vitro blockade of CD1d-mediated lipid antigen presentation, disruption of T cell receptor (TCR) signaling, or loss of perforin expression significantly reduce iNKT cell killing. Consistent with these findings, iNKT cell reconstitution of T, B, and NK cell-deficient mice slows EL4 growth in vivo via TCR-CD1d and perforin-dependent mechanisms. Together, these observations establish that iNKT cells are sufficient to control the growth of T-lymphoma in vitro and in vivo. They also suggest that the induction of iNKT cell cytotoxic responses in situ might serve as a more effective strategy to prevent and/or treat CD1d+ cancers, such as T-lymphoma. PMID:24563871

  3. Effects of different algaecides on the photosynthetic capacity, cell integrity and microcystin-LR release of Microcystis aeruginosa

    International Nuclear Information System (INIS)

    Zhou, Shiqing; Shao, Yisheng; Gao, Naiyun; Deng, Yang; Qiao, Junlian; Ou, Huase; Deng, Jing

    2013-01-01

    Bench scale tests were conducted to study the effects of four common algaecides, including copper sulfate, hydrogen peroxide, diuron and ethyl 2-methylacetoacetate (EMA) on the photosynthetic capacity, cell integrity and microcystin-LR (MC-LR) release of Microcystis aeruginosa. The release of potassium (K + ) from cell membrane during algaecide exposure was also analyzed. The three typical photosynthetic parameters, including the effective quantum yield (φ e ), photosynthetic efficiency (α) and maximal electron transport rate (rETR max ), were measured by a pulse amplitude modulated (PAM) fluorometry. Results showed that the photosynthetic capacity was all inhibited by the four algaecides, to different degrees, by limiting the energy capture in photosynthesis, and blocking the electron transfer chain in primary reaction. For example, at high diuron concentration (7.5 mg L −1 ), φ e , α and rETR max decreased from 0.46 to 0.19 (p −2 s −1 /μmol photons m −2 s −1 , and from 160.7 to 0.1 (p −2 s −1 compared with the control group after 96 h of exposure, respectively. Furthermore, the increase of algaecide dose could lead to the cell lysis, as well as release of intracellular MC-LR that enhanced the accumulation of extracellular MC-LR. The order of MC-LR release potential for the four algaecides was CuSO 4 > H 2 O 2 > diuron > EMA. Highlights: • PAM was used to investigate the effects of algaecides on Microcystis aeruginosa. • We estimate the release of potassium (K + ) from cell membrane for cell lysis. • The risk of microcystin-LR release was evaluated after algaecides exposure. • The order of MC-LR release potential was copper sulfate > hydrogen peroxide > diuron > ethyl 2-methylacetoacetate

  4. Cytotoxicity towards human endothelial cells, induced by neutrophil myeloperoxidase: protection by ceftazidime

    Directory of Open Access Journals (Sweden)

    M. Mathy-Hartert

    1995-01-01

    Full Text Available We investigated the effects of the antibiotic ceftazidime (CAZ on the cytolytic action of the neutrophil myeloperoxidase–hydrogen peroxide–chloride anion system (MPO/H2O2/Cl−. In this system, myeloperoxidase catalyses the conversion of H2O2 and CI− to the cytotoxic agent HOCl. Stimulated neutrophils can release MPO into the extracellular environment and then may cause tissue injury through direct endothelial cells lysis. We showed that human umbilical vein endothelial cells (HUVEC were capable of taking up active MPO. In presence of H2O2 (10−4 M, this uptake was accompanied by cell lysis. The cytolysis was estimated by the release of 51Cr from HUVEC and expressed as an index of cytotoxicity (IC. Dose dependent protection was obtained for CAZ concentrations ranging from 10−5 to 10−3 M;this can be attributed to inactivation of HOCl by the drug. This protection is comparable to that obtained with methionine and histidine, both of which are known to neutralize HOCl. This protection by CAZ could also be attributed to inactivation of H2O2, but when cytolysis was achieved with H2O2 or O2− generating enzymatic systems, no protection by CAZ was observed. Moreover, the peroxidation activity of MPO (action on H2O2 was not affected by CAZ, while CAZ prevented the chlorination activity of MPO (chlorination of monochlorodimedon. So, we concluded that CAZ acts via HOCl inactivation. These antioxidant properties of CAZ may be clinically useful in pathological situations where excessive activation of neutrophils occurs, such as in sepsis.

  5. HIV-specific cytotoxic T lymphocyte precursors exist in a CD28-CD8+ T cell subset and increase with loss of CD4 T cells.

    Science.gov (United States)

    Lewis, D E; Yang, L; Luo, W; Wang, X; Rodgers, J R

    1999-06-18

    To determine whether the CD28-CD8+ T cells that develop during HIV infection contain HIV-specific cytotoxic precursor cells. CD8 subpopulations from six asymptomatic HIV-positive adults, with varying degrees of CD4 T cell loss, were sorted by flow cytometry and HIV-specific precursor cytotoxic T lymphocyte frequencies were measured. Three populations of CD8 T cells were tested: CD28+CD5-- T cells, CD28-CD57+ T cells (thought to be memory cells) and CD28-CD57- T cells (function unknown). Sorted CD8 subsets were stimulated with antigen presenting cells expressing HIV-1 Gag/Pol molecules. Cytotoxic T cell assays on Gag/Pol expressing 51Cr-labeled Epstein-Barr virus transformed autologous B cells lines or control targets were performed after 2 weeks. Specific lysis and precursor frequencies were calculated. Both CD28 positive and CD28-CD57+ populations contained appreciable numbers of precursors (9-1720 per 10(6) CD8+ T cells). However, the CD28-CD57- population had fewer precursors in five out of six people studied. More CD28 positive HIV-specific cytotoxic T lymphocyte precursors were found in patients with CD4:CD8 ratios > 1, whereas more CD28-CD57+ precursors were found in patients whose CD4:CD8 ratios were < 1 (r2, 0.68). Memory HIV-specific precursor cytotoxic T lymphocytes are found in both CD28 positive and CD28-CD8+ cells, however, a CD28-CD57- subpopulation had fewer. Because CD28-CD57+ cells are antigen-driven with limited diversity, the loss of CD28 on CD8 T cells during disease progression may reduce the response to new HIV mutations; this requires further testing.

  6. PRODIGIOSIN INDUCES AUTOLYSINS IN ACTIVELY GROWN Bacillus subtilis CELLS

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    Tjasa eDanevcic

    2016-01-01

    Full Text Available Prodigiosin produced by marine bacterium Vibrio ruber DSM 14379 exhibits a potent antimicrobial activity against a broad range of Gram positive and Gram negative bacteria. The mechanism of prodigiosin antimicrobial action, however, is not known. In this work, the effect of prodigiosin on B. subtilis growth, cell membrane leakage, and induction of autolysins was studied. Treating B. subtilis with prodigiosin resulted in rapid decline of optical density and increased cell membrane leakage measured by β-galactosidase activity. Cell lysis was initiated immediately after treatment with prodigiosin in the middle exponential phase and was completed within two hours. Lytic activity of prodigiosin in mutant strains with impaired autolysin genes lytABCD decreased for 80 % compared to the wild-type strain, while in lytABCDEF mutant strain prodigiosin had no bacteriolytic but only bacteriostatic effect. Fast prodigiosin lytic activity on individual B. subtilis cells was confirmed by a modified comet assay. The results indicate that prodigiosin autolysin induction in B. subtilis is growth phase dependent.

  7. Association of myocardial cell necrosis with experimental cardiac hypertrophy

    Energy Technology Data Exchange (ETDEWEB)

    Revis, N W; Cameron, A J.V.

    1979-01-01

    Cardiac hypertrophy was induced in rabbits by injecting thyroxime or isoprenaline, or by surgically constricting the abdominal aorta. An increase in heart weight was associated with a change in the ratios of bound to free forms of five lysosomal enzymes, a change in serum creatine phosphokinase and lactate dehydrogenase, and a change in the morphology of the myocardial cells. Isoprenaline treatment for 5 days induced a maximal change in heart weight, in the ratio of lysosomal enzymes, and in the serum enzymes. Thyroxine treatment was required for 15 days before maximal changes in heart weight, ratio, and serum enzymes were observed. In contrast, coarctation of the aorta caused a progressive change in heart weight, in the ratio of lysosomal enzymes, and in serum enzymes. These results suggest that necrosis of the myocardial cells does indeed accompany cardiac hypertrophy. It was further observed that autophagosomes, degenerating mitochondria in the myocardial cells during the induction of cardiac hypertrophy, and myofibril lysis were found, all of which confirms the suggestion of myocardial cell necrosis in the experimentally enlarged heart.

  8. Semi-automated limit-dilution assay and clonal expansion of all T-cell precursors of cytotoxic lymphocytes

    International Nuclear Information System (INIS)

    Wilson, A.; Chen, W.-F.; Scollay, R.; Shortman, K.

    1982-01-01

    A limit-dilution microculture system is described, where almost all precursor T cells of the cytotoxic lineage (CTL-p) develop into extended clones of cytotoxic T cells (CTL), which are then detected with a new radio-autographic 111 In-release assay. The principle is to polyclonally activate all T cells with concanavalin A, to expand the resultant clones over an 8-9 day period in cultures saturated with growth factors, then to detect all clones with cytotoxic function by phytohaemagglutinin mediated lysis of P815 tumour cells. The key variables for obtaining high cloning efficiency are the use of flat-bottomed 96-well culture trays, the use of appropriately irradiated spleen filler cells, and the inclusion of a T-cell growth factor supplement. Cultures are set up at input levels of around one T cell per well. Forty percent of T cells then form CTL clones readily detected by the cytotoxic assay. The lytic activity of the average clone is equivalent to 3000 CTL, but clone size appears to be much larger. The precursor cells are predominantly if not entirely from the Lyt 2 + T-cell subclass and almost all cells of this subclass form cytolytic clones. Analysis of the frequency of positive cultures shows a good fit to the expected Poisson distribution, with no evidence of the CTL-p frequency estimates being distorted by helper or suppressor effects. (Auth.)

  9. Semi-automated limit-dilution assay and clonal expansion of all T-cell precursors of cytotoxic lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, A.; Chen, W.F.; Scollay, R.; Shortman, K. (Walter and Eliza Hall Inst. of Medical Research, Parkville (Australia))

    1982-08-13

    A limit-dilution microculture system is described, where almost all precursor T cells of the cytotoxic lineage (CTL-p) develop into extended clones of cytotoxic T cells (CTL), which are then detected with a new radio-autographic /sup 111/In-release assay. The principle is to polyclonally activate all T cells with concanavalin A, to expand the resultant clones over an 8-9 day period in cultures saturated with growth factors, then to detect all clones with cytotoxic function by phytohaemagglutinin mediated lysis of P815 tumour cells. The key variables for obtaining high cloning efficiency are the use of flat-bottomed 96-well culture trays, the use of appropriately irradiated spleen filler cells, and the inclusion of a T-cell growth factor supplement. Cultures are set up at input levels of around one T cell per well. Forty percent of T cells then form CTL clones readily detected by the cytotoxic assay. The lytic activity of the average clone is equivalent to 3000 CTL, but clone size appears to be much larger. The precursor cells are predominantly if not entirely from the Lyt 2/sup +/ T-cell subclass and almost all cells of this subclass form cytolytic clones. Analysis of the frequency of positive cultures shows a good fit to the expected Poisson distribution, with no evidence of the CTL-p frequency estimates being distorted by helper or suppressor effects.

  10. Comparison of lentiviral and sleeping beauty mediated αβ T cell receptor gene transfer.

    Directory of Open Access Journals (Sweden)

    Anne-Christine Field

    Full Text Available Transfer of tumour antigen-specific receptors to T cells requires efficient delivery and integration of transgenes, and currently most clinical studies are using gamma retroviral or lentiviral systems. Whilst important proof-of-principle data has been generated for both chimeric antigen receptors and αβ T cell receptors, the current platforms are costly, time-consuming and relatively inflexible. Alternative, more cost-effective, Sleeping Beauty transposon-based plasmid systems could offer a pathway to accelerated clinical testing of a more diverse repertoire of recombinant high affinity T cell receptors. Nucleofection of hyperactive SB100X transposase-mediated stable transposition of an optimised murine-human chimeric T cell receptor specific for Wilm's tumour antigen from a Sleeping Beauty transposon plasmid. Whilst transfer efficiency was lower than that mediated by lentiviral transduction, cells could be readily enriched and expanded, and mediated effective target cells lysis in vitro and in vivo. Integration sites of transposed TCR genes in primary T cells were almost randomly distributed, contrasting the predilection of lentiviral vectors for transcriptionally active sites. The results support exploitation of the Sleeping Beauty plasmid based system as a flexible and adaptable platform for accelerated, early-phase assessment of T cell receptor gene therapies.

  11. Cell Vacuolation Caused by Vibrio cholerae Hemolysin

    Science.gov (United States)

    Figueroa-Arredondo, Paula; Heuser, John E.; Akopyants, Natalia S.; Morisaki, J. Hiroshi; Giono-Cerezo, Silvia; Enríquez-Rincón, Fernando; Berg, Douglas E.

    2001-01-01

    Non-O1 strains of Vibrio cholerae implicated in gastroenteritis and diarrhea generally lack virulence determinants such as cholera toxin that are characteristic of epidemic strains; the factors that contribute to their virulence are not understood. Here we report that at least one-third of diarrhea-associated nonepidemic V. cholerae strains from Mexico cause vacuolation of cultured Vero cells. Detailed analyses indicated that this vacuolation was related to that caused by aerolysin, a pore-forming toxin of Aeromonas; it involved primarily the endoplasmic reticulum at early times (∼1 to 4 h after exposure), and resulted in formation of large, acidic, endosome-like multivesicular vacuoles (probably autophagosomes) only at late times (∼16 h). In contrast to vacuolation caused by Helicobacter pylori VacA protein, that induced by V. cholerae was exacerbated by agents that block vacuolar proton pumping but not by endosome-targeted weak bases. It caused centripetal redistribution of endosomes, reflecting cytoplasmic alkalinization. The gene for V. cholerae vacuolating activity was cloned and was found to correspond to hlyA, the structural gene for hemolysin. HlyA protein is a pore-forming toxin that causes ion leakage and, ultimately, eukaryotic cell lysis. Thus, a distinct form of cell vacuolation precedes cytolysis at low doses of hemolysin. We propose that this vacuolation, in itself, contributes to the virulence of V. cholerae strains, perhaps by perturbing intracellular membrane trafficking or ion exchange in target cells and thereby affecting local intestinal inflammatory or other defense responses. PMID:11179335

  12. iNKT cell cytotoxic responses control T-lymphoma growth in vitro and in vivo .

    Science.gov (United States)

    Bassiri, Hamid; Das, Rupali; Guan, Peng; Barrett, David M; Brennan, Patrick J; Banerjee, Pinaki P; Wiener, Susan J; Orange, Jordan S; Brenner, Michael B; Grupp, Stephan A; Nichols, Kim E

    2014-01-01

    Invariant natural killer T (iNKT) cells comprise a lineage of CD1d-restricted glycolipid-reactive T lymphocytes with important roles in host immunity to cancer. iNKT cells indirectly participate in antitumor responses by inducing dendritic cell maturation and producing cytokines that promote tumor clearance by CD8+ T and NK cells. Although iNKT cells thereby act as potent cellular adjuvants, it is less clear whether they directly control the growth of tumors. To gain insights into the direct contribution of iNKT cells to tumor immune surveillance, we developed in vitro and in vivo systems to selectively examine the antitumor activity of iNKT cells in the absence of other cytolytic effectors. Using the EL4 T-lymphoma cell line as a model, we found that iNKT cells exert robust and specific lysis of tumor cells in vitro in a manner that is differentially induced by iNKT cell agonists of varying T-cell receptor (TCR) affinities, such as OCH, α-galactosyl ceramide, and PBS44. In vitro blockade of CD1d-mediated lipid antigen presentation, disruption of TCR signaling, or loss of perforin expression significantly reduce iNKT cell killing. Consistent with these findings, iNKT cell reconstitution of T, B, and NK cell–deficient mice slows EL4 growth in vivo via TCR-CD1d and perforin-dependent mechanisms. Together, these observations establish that iNKT cells are sufficient to control the growth of T lymphoma in vitro and in vivo. They also suggest that the induction of iNKT cell cytotoxic responses in situ might serve as a more effective strategy to prevent and/or treat CD1d+ cancers, such as T lymphoma. ©2013 AACR.

  13. Small Cell Lung Cancer Patient with Profound Hyponatremia and Acute Neurological Symptoms: An Effective Treatment with Fludrocortisone

    Directory of Open Access Journals (Sweden)

    Jana Jaal

    2015-01-01

    Full Text Available Hyponatremia is a frequent electrolyte abnormality in patients with small cell lung cancer (SCLC. Being usually asymptomatic, hyponatremia may cause symptoms like nausea, fatigue, disorientation, headache, muscle cramps, or even seizures, particularly if severe and rapid decrease of serum sodium levels occurs. Here we report a case of SCLC patient with severe hyponatremia and acute neurological symptoms that developed 2 days after the first course of second-line chemotherapy, most probably due to the release of antidiuretic hormone (ADH, also known as arginine vasopressin during lysis of the tumour cells. Initial treatment consisted of continuous administration of hypertonic saline that resulted in improvement of patient’s neurological status. However, to obtain a persistent increase in serum sodium level, pharmacological intervention with oral fludrocortisone 0.1 mg twice daily was needed. We can therefore conclude that mineralocorticoids may be used to correct hyponatremia in SCLC patients when appropriate.

  14. Post-translational control of RIPK3 and MLKL mediated necroptotic cell death [version 1; referees: 4 approved

    Directory of Open Access Journals (Sweden)

    James M. Murphy

    2015-11-01

    Full Text Available Several programmed lytic and necrotic-like cell death mechanisms have now been uncovered, including the recently described receptor interacting protein kinase-3 (RIPK3-mixed lineage kinase domain-like (MLKL-dependent necroptosis pathway. Genetic experiments have shown that programmed necrosis, including necroptosis, can play a pivotal role in regulating host-resistance against microbial infections. Alternatively, excess or unwarranted necroptosis may be pathological in autoimmune and autoinflammatory diseases. This review highlights the recent advances in our understanding of the post-translational control of RIPK3-MLKL necroptotic signaling. We discuss the critical function of phosphorylation in the execution of necroptosis, and highlight the emerging regulatory roles for several ubiquitin ligases and deubiquitinating enzymes. Finally, based on current evidence, we discuss the potential mechanisms by which the essential, and possibly terminal, necroptotic effector, MLKL, triggers the disruption of cellular membranes to cause cell lysis.

  15. The impact of locally multiply damaged sites (LMDS) induced by ionizing radiation in mammalian cells

    International Nuclear Information System (INIS)

    Averbeck, D.; Boucher, D.

    2006-01-01

    DNA strand-breaks we were able to show that uncontrolled oxidation of DNA during cell lysis and DNA extraction gives rise to artificial DSB. If one avoids this oxidation by adding an antioxidant and/or an iron chelating agent (to inhibit possible Fenton reactions and the formation of OH radicals) before cell-lysis, the amount of LMDS decreases to very low, nearly insignificant levels. This holds for mammalian cells after low LET and high LET radiation (Ar+ ions). The induction of LMDS turned out to be neither dose- nor dose-rate dependent. Furthermore, we demonstrate that additional DSB, i.e. 'LMDS' can be detected by PFGE and enzymatic treatment when adding H 2 O 2 during cell-lysis. Thus, it is clear that the actual method used for the detection of these lesions induced in living cells is inadequate and that there is at present no firm experimental evidence for the presence of LMDS composed of oxidative damage after low or high LET irradiation in mammalian cells that can be related to radiation responses. At present, other possible approaches are tested that might allow a better definition of complex radiation-induced lesions in mammalian cells such as complex DSB. (authors)

  16. The impact of locally multiply damaged sites (LMDS) induced by ionizing radiation in mammalian cells

    Energy Technology Data Exchange (ETDEWEB)

    Averbeck, D.; Boucher, D. [Institut Curie-Section de Recherche, UMR2027 CNRS, LCR-V28 du CEA, Centre Universitaire, 91405 Orsay Cedex (France)

    2006-07-01

    into DNA strand-breaks we were able to show that uncontrolled oxidation of DNA during cell lysis and DNA extraction gives rise to artificial DSB. If one avoids this oxidation by adding an antioxidant and/or an iron chelating agent (to inhibit possible Fenton reactions and the formation of OH radicals) before cell-lysis, the amount of LMDS decreases to very low, nearly insignificant levels. This holds for mammalian cells after low LET and high LET radiation (Ar+ ions). The induction of LMDS turned out to be neither dose- nor dose-rate dependent. Furthermore, we demonstrate that additional DSB, i.e. 'LMDS' can be detected by PFGE and enzymatic treatment when adding H{sub 2}O{sub 2} during cell-lysis. Thus, it is clear that the actual method used for the detection of these lesions induced in living cells is inadequate and that there is at present no firm experimental evidence for the presence of LMDS composed of oxidative damage after low or high LET irradiation in mammalian cells that can be related to radiation responses. At present, other possible approaches are tested that might allow a better definition of complex radiation-induced lesions in mammalian cells such as complex DSB. (authors)

  17. T cells in chronic lymphocytic leukaemia display an exhausted phenotype and impaired functionality that can be restored by chemotherapy

    International Nuclear Information System (INIS)

    Gassner, F.

    2012-01-01

    In chronic lymphocytic leukaemia (CLL), beside a massive accumulation of neoplastic B cells, tumour-induced deficiencies in autologous T cells have been reported that impede efficient tumour control and might even support survival of the malignant clone. Here, we investigated our hypothesis that T cells in CLL, due to the persistent availability of tumour antigen, are exhausted, and that reduction of tumour load by chemotherapy might restore T cell functions. We could show that T cells in CLL patients and in a CLL mouse model display an exhausted phenotype, with high expression of the inhibitory surface receptor PD-1, that is clearly induced by the presence of tumour cells. Although the PD-1 ligand PD-L1 is not expressed on peripheral CLL cells, abundant expression could be shown in lymph node sections. Intriguingly, blocking the PD-1/PD-L1 pathway increased short term tumour lysis in a murine in vivo cytotoxicity assay. Furthermore, we present data that after cytoreduction by fludarabine, a standard chemotherapy agent for CLL, the surviving T cell pool consists mainly of fully functional memory T cells with high proliferative potential and increased secretion of pro-inflammatory Th1 cytokines. Taken together, we conclude that the impaired tumour surveillance observed in CLL might be rooted in the exhaustion of tumour-specific effector T cells. A combination of cytodepletion by chemotherapy and blockade of PD-1 might hence represent a novel therapeutic approach for CLL. (author) [de

  18. Squamous cell carcinoma of the canine nasal cavity and frontal sinus: eight cases

    International Nuclear Information System (INIS)

    Rogers, K.S.; Walker, M.A.; Helman, R.G.

    1996-01-01

    Squamous cell carcinoma of the canine nasal cavity and frontal sinus was diagnosed in eight cases between May 1988 and April 1994. The most common presenting complaints were nasal discharge, including epistaxis; sneezing; and facial deformity or exophthalmos. Metastasis was not identified in any case, but bone lysis and invasion into tissues outside the nasal cavity were noted in five cases. Computed tomograms were performed in five cases and were more useful than radiographs in determining the extent of neoplastic involvement. Euthanasia was performed within one week of diagnosis in three cases at the owner's request; one case died at home within one month; and the remaining four cases were euthanized within eight months due to progressive clinical signs. The mean survival time in these eight cases was three months, with a range of zero weeks to eight months

  19. Management of Fusarium Wilt using mycolytic enzymes produced by ...

    African Journals Online (AJOL)

    Aghomotsegin

    Trichoderma strain to manage the Fusarium wilt disease of Cicer aritenum under in vitro conditions. We also studied ... antibiosis, competition, parasitism and cell lysis can ideally be ... hydrolytic enzymes associated with fungal cell wall lysis,.

  20. Highly efficient elimination of colorectal tumor-initiating cells by an EpCAM/CD3-bispecific antibody engaging human T cells.

    Directory of Open Access Journals (Sweden)

    Ines Herrmann

    2010-10-01

    Full Text Available With their resistance to genotoxic and anti-proliferative drugs and potential to grow tumors and metastases from very few cells, cancer stem or tumor-initiating cells (TICs are a severe limitation for the treatment of cancer by conventional therapies. Here, we explored whether human T cells that are redirected via an EpCAM/CD3-bispecific antibody called MT110 can lyse colorectal TICs and prevent tumor growth from TICs. MT110 recognizes EpCAM, a cell adhesion molecule expressed on TICs from diverse human carcinoma, which was recently shown to promote tumor growth through engagement of elements of the wnt pathway. MT110 was highly potent in mediating complete redirected lysis of KRAS-, PI3 kinase- and BRAF-mutated colorectal TICs, as demonstrated in a soft agar assay. In immunodeficient mice, MT110 prevented growth of tumors from a 5,000-fold excess of a minimally tumorigenic TIC dose. T cells engaged by MT110 may provide a potent therapeutic means to eradicate TICs and bulk tumor cells derived thereof.

  1. A quantitative method to evaluate mesenchymal stem cell lipofection using real-time PCR.

    Science.gov (United States)

    Ribeiro, S C; Mendes, R; Madeira, C; Monteiro, G A; da Silva, C L; Cabral, J M S

    2010-01-01

    Genetic modification of human mesenchymal stem cells (MSC) is a powerful tool to improve the therapeutic utility of these cells and to increase the knowledge on their regulation mechanisms. In this context, strong efforts have been made recently to develop efficient nonviral gene delivery systems. Although several studies addressed this question most of them use the end product of a reporter gene instead of the DNA uptake quantification to test the transfection efficiency. In this study, we established a method based on quantitative real-time PCR (RT-PCR) to determine the intracellular plasmid DNA copy number in human MSC after lipofection. The procedure requires neither specific cell lysis nor DNA purification. The influence of cell number on the RT-PCR sensitivity was evaluated. The method showed good reproducibility, high sensitivity, and a wide linear range of 75-2.5 x 10⁶ plasmid DNA copies per cell. RT-PCR results were then compared with the percentage of transfected cells assessed by flow cytometry analysis, which showed that flow cytometry-based results are not always proportional to plasmid cellular uptake determined by RT-PCR. This work contributed for the establishment of a rapid quantitative assay to determine intracellular plasmid DNA in stem cells, which will be extremely beneficial for the optimization of gene delivery strategies. © 2010 American Institute of Chemical Engineers

  2. MECHANISM OF ACTION OF ANTIBIOTICS WHICH INHIBIT SYNTHESIS OF BACTERIAL CELL WALL

    Directory of Open Access Journals (Sweden)

    Indira Mujezinović

    2013-03-01

    Full Text Available Bacterial cell possess a cell wall, which is a main difference from mammalian cells. Its basic function is to provide the strength of bacteria, keeps its shape and provides an unusually high internal osmotic pressure. Synthesis of (construction of bacterial cell wall occurs in at least three phases. All of these three phases can be influence by a variety of antibiotics in way to inhibit its synthesis. The most important drugs that act in this manner are ß-lactam antibiotics (penicillins, cephalosporins, cephamycins and other ß-lactams. They interfere with the synthesis of the bacterial cell wall peptidoglycan. After attachment to penicillin binding proteins (PBP on bacteria, they inhibit the transpeptidation enzyme that cross-links the peptide chain attached to the backbone of the peptidoglycan. The final bactericidal event is the inactivation of an inhibitor of autolytic enzymes in the cell wall, wich leads to lysis of the bacteria. Vancomycin inhibits the release of the building block unit from the carrier, thus preventing its addition to the growing end of the peptidoglycan. Cycloserine, which is a structural analogue of D-alanine, prevents the addition of the two terminal alanine residue to the initial tripeptide side-chain on N-acetylmuramic acid by competitive inhibition. Bacitracin interferes with the regeneration of the lipid carrier by blocking its dephosphorylation. Key words: bacterial cell wall, paptidoglycan, antibiotics, ß-lactams

  3. Mkit: A Cell Migration Assay Based on Microfluidic Device and Smartphone

    Science.gov (United States)

    Yang, Ke; Wu, Jiandong; Peretz-Soroka, Hagit; Zhu, Ling; Li, Zhigang; Sang, Yaoshuo; Hipolito, Jolly; Zhang, Michael; Santos, Susy; Hillier, Craig; de Faria, Ricardo Lobato; Liu, Yong; Lin, Francis

    2017-01-01

    Mobile sensing based on the integration of microfluidic device and smartphone, so-called MS2 technology, has enabled many applications over recent years, and continues to stimulate growing interest in both research communities and industries. In particular, it has been envisioned that MS2 technology can be developed for various cell functional assays to enable basic research and clinical applications. Toward this direction, in this paper, we describe the development of a MS2-based cell functional assay for testing cell migration (the Mkit). The system is constructed as an integrated test kit, which includes microfluidic chips, a smartphone-based imaging platform, the phone apps for image capturing and data analysis, and a set of reagent and accessories for performing the cell migration assay. We demonstrated that the Mkit can effectively measure purified neutrophil and cancer cell chemotaxis. Furthermore, neutrophil chemotaxis can be tested from a drop of whole blood using the Mkit with red blood cell (RBC) lysis. The effects of chemoattractant dose and gradient profile on neutrophil chemotaxis were also tested using the Mkit. In addition to research applications, we demonstrated the effective use of the Mkit for on-site test at the hospital and for testing clinical samples from chronic obstructive pulmonary disease patient. Thus, this developed Mkit provides an easy and integrated experimental platform for cell migration related research and potential medical diagnostic applications. PMID:28772229

  4. Mkit: A cell migration assay based on microfluidic device and smartphone.

    Science.gov (United States)

    Yang, Ke; Wu, Jiandong; Peretz-Soroka, Hagit; Zhu, Ling; Li, Zhigang; Sang, Yaoshuo; Hipolito, Jolly; Zhang, Michael; Santos, Susy; Hillier, Craig; de Faria, Ricardo Lobato; Liu, Yong; Lin, Francis

    2018-01-15

    Mobile sensing based on the integration of microfluidic device and smartphone, so-called MS 2 technology, has enabled many applications over recent years, and continues to stimulate growing interest in both research communities and industries. In particular, it has been envisioned that MS 2 technology can be developed for various cell functional assays to enable basic research and clinical applications. Toward this direction, in this paper, we describe the development of a MS 2 -based cell functional assay for testing cell migration (the M kit ). The system is constructed as an integrated test kit, which includes microfluidic chips, a smartphone-based imaging platform, the phone apps for image capturing and data analysis, and a set of reagent and accessories for performing the cell migration assay. We demonstrated that the M kit can effectively measure purified neutrophil and cancer cell chemotaxis. Furthermore, neutrophil chemotaxis can be tested from a drop of whole blood using the M kit with red blood cell (RBC) lysis. The effects of chemoattractant dose and gradient profile on neutrophil chemotaxis were also tested using the M kit . In addition to research applications, we demonstrated the effective use of the M kit for on-site test at the hospital and for testing clinical samples from chronic obstructive pulmonary disease patient. Thus, this developed M kit provides an easy and integrated experimental platform for cell migration related research and potential medical diagnostic applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Stem Cells

    Science.gov (United States)

    Stem cells are cells with the potential to develop into many different types of cells in the body. ... the body. There are two main types of stem cells: embryonic stem cells and adult stem cells. Stem ...

  6. Regulation of NKG2D-Dependent NK Cell Functions: The Yin and the Yang of Receptor Endocytosis

    Directory of Open Access Journals (Sweden)

    Rosa Molfetta

    2017-08-01

    Full Text Available Natural-killer receptor group 2, member D (NKG2D is a well characterized natural killer (NK cell activating receptor that recognizes several ligands poorly expressed on healthy cells but up-regulated upon stressing stimuli in the context of cancer or viral infection. Although NKG2D ligands represent danger signals that render target cells more susceptible to NK cell lysis, accumulating evidence demonstrates that persistent exposure to ligand-expressing cells causes the decrease of NKG2D surface expression leading to a functional impairment of NKG2D-dependent NK cell functions. Upon ligand binding, NKG2D is internalized from the plasma membrane and sorted to lysosomes for degradation. However, receptor endocytosis is not only a mechanism of receptor clearance from the cell surface, but is also required for the proper activation of signalling events leading to the functional program of NK cells. This review is aimed at providing a summary of current literature relevant to the molecular mechanisms leading to NKG2D down-modulation with particular emphasis given to the role of NKG2D endocytosis in both receptor degradation and signal propagation. Examples of chronic ligand-induced down-regulation of NK cell activating receptors other than NKG2D, including natural cytotoxicity receptors (NCRs, DNAX accessory molecule-1 (DNAM1 and CD16, will be also discussed.

  7. FRET imaging of hemoglobin concentration in Plasmodium falciparum-infected red cells.

    Directory of Open Access Journals (Sweden)

    Alessandro Esposito

    Full Text Available During its intraerythrocytic asexual reproduction cycle Plasmodium falciparum consumes up to 80% of the host cell hemoglobin, in large excess over its metabolic needs. A model of the homeostasis of falciparum-infected red blood cells suggested an explanation based on the need to reduce the colloid-osmotic pressure within the host cell to prevent its premature lysis. Critical for this hypothesis was that the hemoglobin concentration within the host cell be progressively reduced from the trophozoite stage onwards.The experiments reported here were designed to test this hypothesis by direct measurements of the hemoglobin concentration in live, infected red cells. We developed a novel, non-invasive method to quantify the hemoglobin concentration in single cells, based on Förster resonance energy transfer between hemoglobin molecules and the fluorophore calcein. Fluorescence lifetime imaging allowed the quantitative mapping of the hemoglobin concentration within the cells. The average fluorescence lifetimes of uninfected cohorts was 270+/-30 ps (mean+/-SD; N = 45. In the cytoplasm of infected cells the fluorescence lifetime of calcein ranged from 290+/-20 ps for cells with ring stage parasites to 590+/-13 ps and 1050+/-60 ps for cells with young trophozoites and late stage trophozoite/early schizonts, respectively. This was equivalent to reductions in hemoglobin concentration spanning the range from 7.3 to 2.3 mM, in line with the model predictions. An unexpected ancillary finding was the existence of a microdomain under the host cell membrane with reduced calcein quenching by hemoglobin in cells with mature trophozoite stage parasites.The results support the predictions of the colloid-osmotic hypothesis and provide a better understanding of the homeostasis of malaria-infected red cells. In addition, they revealed the existence of a distinct peripheral microdomain in the host cell with limited access to hemoglobin molecules indicating the

  8. High temperature induced disruption of the cell wall integrity and structure in Pleurotus ostreatus mycelia.

    Science.gov (United States)

    Qiu, Zhiheng; Wu, Xiangli; Gao, Wei; Zhang, Jinxia; Huang, Chenyang

    2018-05-30

    Fungal cells are surrounded by a tight cell wall to protect them from harmful environmental conditions and to resist lysis. The synthesis and assembly determine the shape, structure, and integrity of the cell wall during the process of mycelial growth and development. High temperature is an important abiotic stress, which affects the synthesis and assembly of cell walls. In the present study, the chitin and β-1,3-glucan concentrations in the cell wall of Pleurotus ostreatus mycelia were changed after high-temperature treatment. Significantly higher chitin and β-1,3-glucan concentrations were detected at 36 °C than those incubated at 28 °C. With the increased temperature, many aberrant chitin deposition patches occurred, and the distribution of chitin in the cell wall was uneven. Moreover, high temperature disrupts the cell wall integrity, and P. ostreatus mycelia became hypersensitive to cell wall-perturbing agents at 36 °C. The cell wall structure tended to shrink or distorted after high temperature. The cell walls were observed to be thicker and looser by using transmission electron microscopy. High temperature can decrease the mannose content in the cell wall and increase the relative cell wall porosity. According to infrared absorption spectrum, high temperature broke or decreased the glycosidic linkages. Finally, P. ostreatus mycelial cell wall was easily degraded by lysing enzymes after high-temperature treatment. In other words, the cell wall destruction caused by high temperature may be a breakthrough for P. ostreatus to be easily infected by Trichoderma.

  9. Investigation of the Cry4B-prohibitin interaction in Aedes aegypti cells.

    Science.gov (United States)

    Kuadkitkan, Atichat; Smith, Duncan R; Berry, Colin

    2012-10-01

    Bacillus thuringiensis (Bt) produces insecticidal toxins active against insects. Cry4B, one of the major insecticidal toxins produced by Bt subsp. israelensis, is highly toxic to mosquitoes in the genus Aedes: the major vectors of dengue, yellow fever, and chikungunya. Previous work has shown that Cry4B binds to several mid-gut membrane proteins in Aedes aegypti larvae including prohibitin, a protein recently identified as a receptor that also mediates entry of dengue virus into Aedes cells. This study confirms the interaction between Cry4B and prohibitin by co-immunoprecipitation analysis and demonstrates colocalization of prohibitin and Cry4B by confocal microscopy. While activated Cry4B toxin showed high larvicidal activity, it was not cytotoxic to two Aedes cell lines, allowing determination of its effect on dengue virus infectivity in the absence of Cry4B-induced cell lysis. Pre-exposure of Aedes cells to Cry4B resulted in a significant reduction in the number of infected cells compared to untreated cells.

  10. Energy and calcium ion dependence of proteolysis during sporulation of Bacillus subtilis cells

    International Nuclear Information System (INIS)

    O'Hara, M.B.; Hageman, J.H.

    1990-01-01

    The authors have shown, with an optimized [ 14 C]leucine-labeling and chasing procedure, that intracellular protein degradation in sporulating cells of Bacillus subtilis 168 (trpC2) is apparently energy dependent. Sodium arsenate, sodium azide, carbonyl cyanide m-chlorophenylhydrozone, and N,N'-dicyclohexylcarbodiimide, at levels which did not induce appreciable lysis (≤ 10%) over 10-h periods of sporulation, inhibited intracellular proteolysis by 13 to 93%. Exponentially growing cells acquired arsenate resistance. In contrast to earlier reports, the authors found that chloramphenicol strongly inhibited proteolysis even when added 6 h into the sporulation process. Restricting the calcium ion concentration in the medium had no effect on rates or extent of vegetative growth, strongly inhibited sporulation, and inhibited rates of proteolysis by 60% or more. Inhibitors of energy metabolism, at the same levels which inhibited proteolysis, did not affect the rate or degree of uptake of Ca 2+ by cells. Restricting the Ca 2+ concentration in the medium reduced by threefold of the specific activity in cells of the major intracellular serine proteinase after 12 h of sporulation. finally, cells of a mutant of B. subtilis bearing an insertionally inactivated gene for the Ca 2+ -dependent intracellular proteinase-1 degraded protein in chemically defined sporulation medium at a rate indistinguishable from that of the wild-type cells for period of 8 h

  11. Invasion of Eukaryotic Cells by Legionella Pneumophila: A Common Strategy for all Hosts?

    Directory of Open Access Journals (Sweden)

    Paul S Hoffman

    1997-01-01

    Full Text Available Legionella pneumophila is an environmental micro-organism capable of producing an acute lobar pneumonia, commonly referred to as Legionnaires’ disease, in susceptible humans. Legionellae are ubiquitous in aquatic environments, where they survive in biofilms or intracellularly in various protozoans. Susceptible humans become infected by breathing aerosols laden with the bacteria. The target cell for human infection is the alveolar macrophage, in which the bacteria abrogate phagolysosomal fusion. The remarkable ability of L pneumophila to infect a wide range of eukaryotic cells suggests a common strategy that exploits very fundamental cellular processes. The bacteria enter host cells via coiling phagocytosis and quickly subvert organelle trafficking events, leading to formation of a replicative phagosome in which the bacteria multiply. Vegetative growth continues for 8 to 10 h, after which the bacteria develop into a short, highly motile form called the ‘mature form’. The mature form exhibits a thickening of the cell wall, stains red with the Gimenez stain, and is between 10 and 100 times more infectious than agar-grown bacteria. Following host cell lysis, the released bacteria infect other host cells, in which the mature form differentiates into a Gimenez-negative vegetative form, and the cycle begins anew. Virulence of L pneumophila is considered to be multifactorial, and there is growing evidence for both stage specific and sequential gene expression. Thus, L pneumophila may be a good model system for dissecting events associated with the host-parasite interactions.

  12. Frequency of regulatory T cells determines the outcome of the T-cell-engaging antibody blinatumomab in patients with B-precursor ALL.

    Science.gov (United States)

    Duell, J; Dittrich, M; Bedke, T; Mueller, T; Eisele, F; Rosenwald, A; Rasche, L; Hartmann, E; Dandekar, T; Einsele, H; Topp, M S

    2017-10-01

    Blinatumomab can induce a complete haematological remission in patients in 46.6% with relapsed/refractory B-precursor acute lymphoblastic leukemia (r/r ALL) resulting in a survival benefit when compared with chemotherapy. Only bone marrow blast counts before therapy have shown a weak prediction of response. Here we investigated the role of regulatory T cells (Tregs), measured by CD4/CD25/FOXP3 expression, in predicting the outcome of immunotherapy with the CD19-directed bispecific T-cell engager construct blinatumomab. Blinatumomab responders (n=22) had an average of 4.82% Tregs (confidence interval (CI): 1.79-8.34%) in the peripheral blood, whereas non-responders (n=20) demonstrated 10.25% Tregs (CI: 3.36-65.9%). All other tested markers showed either no prediction value or an inferior prediction level including blast BM counts and the classical enzyme marker lactate dehydrogenase. With a cutoff of 8.525%, Treg enumeration can identify 100% of all blinatumomab responders and exclude 70% of the non-responders. The effect is facilitated by blinatumomab-activated Tregs, leading to interleukin-10 production, resulting in suppression of T-cell proliferation and reduced CD8-mediated lysis of ALL cells. Proliferation of patients' T cells can be restored by upfront removal of Tregs. Thus, enumeration of Treg identifies r/r ALL patients with a high response rate to blinatumomab. Therapeutic removal of Tregs may convert blinatumomab non-responders to responders.

  13. CXCR4 Is Required by a Nonprimate Lentivirus: Heterologous Expression of Feline Immunodeficiency Virus in Human, Rodent, and Feline Cells

    Science.gov (United States)

    Poeschla, Eric M.; Looney, David J.

    1998-01-01

    A heterologous feline immunodeficiency virus (FIV) expression system permitted high-level expression of FIV proteins and efficient production of infectious FIV in human cells. These results identify the FIV U3 element as the sole restriction to the productive phase of replication in nonfeline cells. Heterologous FIV expression in a variety of human cell lines resulted in profuse syncytial lysis that was FIV env specific, CD4 independent, and restricted to cells that express CXCR4, the coreceptor for T-cell-line-adapted strains of human immunodeficiency virus. Stable expression of human CXCR4 in CXCR4-negative human and rodent cell lines resulted in extensive FIV Env-mediated, CXCR4-dependent cell fusion and infection. In feline cells, stable overexpression of human CXCR4 resulted in increased FIV infectivity and marked syncytium formation during FIV replication or after infection with FIV Env-expressing vectors. The use of CXCR4 is a fundamental feature of lentivirus biology independent of CD4 and a shared cellular link to infection and cytopathicity for distantly related lentiviruses that cause AIDS. Their conserved use implicates chemokine receptors as primordial lentivirus receptors. PMID:9658135

  14. A comparison of the cytotoxic activity of eosinophils and other cells by 51chromium release and time lapse microcinematography

    International Nuclear Information System (INIS)

    Sanderson, C.J.; Thomas, J.A.

    1978-01-01

    Antibody dependent cytotoxicity of chicken erythrocytes by purified rat eosinophils, neutrophils, macrophages and K cells has been compared by 51 Cr release and time lapse microcinematography. Techniques have been developed for purifying these effector cell types. Both eosinophils and neutrophils caused rapid release of 51 Cr from erythrocytes. Time lapse observations indicated that this was the result of phagocytosis. Eosinophils showed rapid membrane movement and repeatedly engulfed and regurgitated the erythrocytes. On the other hand, neutrophils became quiescent after phagocytosing erythrocytes, and remained quiescent until the remains of the cell were expelled. Neutrophils presumably have a mechanism for the release of soluble material, as 51 Cr was released rapidly. Macrophages showed a similar quiescence after phagocytosis, but in these cells there was apparently no rapid mechanism to expel material, as there was no significant 51 Cr release over 20 h. K cells appeared to damage chicken erythrocytes more slowly than they destroyed tumour cells. Mast cells caused antibody-independent cytotoxicity which can be attributed to the release of toxic materials. None of these effector cells produced the type of lysis seen with antibody and complement. (author)

  15. Rotavirus infectious particles use lipid rafts during replication for transport to the cell surface in vitro and in vivo

    International Nuclear Information System (INIS)

    Cuadras, Mariela A.; Greenberg, Harry B.

    2003-01-01

    The pathway by which rotavirus is released from the cell is poorly understood but recent work has shown that, prior to cell lysis, rotavirus is released almost exclusively from the apical surface of the infected cell. By virtue of their unique biochemical and physical properties, viruses have exploited lipid rafts for host cell entry and/or assembly. Here we characterized the association of rhesus rotavirus (RRV) with lipid rafts during the rotavirus replication cycle. We found that newly synthesized infectious virus associates with rafts in vitro and in vivo. RRV proteins cosegregated with rafts on density gradients. Viral infectivity and genomic dsRNA also cosegregated with the raft fractions. Confocal microscopic analysis of raft and RRV virion proteins demonstrated colocalization within the cell. In addition, cholesterol depletion interfered with the association of RRV particles with rafts and reduced the release of infectious particles from the cell. Furthermore, murine rotavirus associates with lipid rafts in intestinal epithelial cells during a natural infection in vivo. Our results confirm the association of rotavirus infectious particles with rafts during replication in vitro and in vivo and strongly support the conclusion that this virus uses these microdomains for transport to the cell surface during replication

  16. Cell damage of hepatoma-22 cells exposed to continuous wave ultrasound.

    Science.gov (United States)

    Wang, Pan; Wang, Xiaobing; Liu, Quanhong

    2012-01-01

    The cellular response of hepatoma-22 cells to ultrasonic irradiation and the potential cause for the action were evaluated. Hepatoma-22 cells were subjected to ultrasound irradiation at a frequency of 2.17 MHz and a spatial average intensity of 1.6 W/cm2 for variable periods of time, and several biological parameters were analyzed. The terephthalic acid (TA) dosimetry method was used to evaluate the efficacies of irradiation parameters on the acoustic cavitation activity by monitoring hydroxyl radical (OH) production. Lactate dehydrogenase (LDH) leakage was assayed to investigate cell membrane integrity. The polarization value of fluorescent probe 1,6-diphenyl-1,3,5-hexatriene (DPH) was measured to monitor plasma membrane fluidity. The malonaldehyde content in cells was determined to reflect lipid peroxidation. Trypan blue exclusion was used to detect cell viability. Additionally, electron microscopy was used to observe morphological changes. The generation of intracellular reactive oxygen species, mitochondria swelling and the loss of mitochondria membrane potential were also investigated. The results showed that 1) the concentration of ·OH production by ultrasonic irradiation in air-saturated cell suspensions increased as ultrasound exposure time increased; 2) compared with control, lactate dehydrogenase leakage, the polarization value of 1,6-diphenyl-1,3,5-hexatriene, malonaldehyde content and cell lysis were significantly elevated when cells were treated by ultrasound for 60 s; 3) cytotoxicity by ultrasound irradiation was also accompanied by an increase in production of intracellular reactive oxygen species and dissipation of mitochondria membrane potential as well as by mitochondria swelling. Presently available information indicates that the plasma membrane and mitochondria are the main targets for ultrasound treatment, and free radicals formation such as ·OH due to ultrasound cavitation may play an important role in mediating these cellular response

  17. Killing defect of natural killer cells with the absence of natural killer cytotoxic factors in a child with Hodgkin's disease

    International Nuclear Information System (INIS)

    Komiyama, A.; Kawai, H.; Yamada, S.; Kato, M.; Yanagisawa, M.; Miyagawa, Y.; Akabane, T.

    1987-01-01

    A killing defect of natural killer (NK) cells in the absence of NK cytotoxic factors (NKCF) was first demonstrated in a child with Hodgkin's disease. The patient lacked detectable NK cell activity in every phase of the disease as measured by a four-hour 51 Cr-release assay using K562 cells as a target. The percent lysis at a 40:1 effector:target ratio by the patient's lymphocytes was persistently below 0.3% as compared with the normal lymphocyte value of 46.2% +/- 5.8% (mean +/- SD). NK cell activity was not detectable at effector:target ratios of 10:1 to 80:1 and by prolongation of the incubation time, and the NK cell defect was not restored or improved by lymphocyte stimulation with polyinosinic-polycytidilic acid, interferon (IFN)-alpha, or interleukin 2 (IL 2). The numbers of Leu-7+ cells and Leu-11+ cells were normal as counted by flow cytometry. A single cell-in-agarose assay demonstrated normal numbers of target binding cells (TBCs), and they showed the morphology of large granular lymphocytes. However, there were no TBCs with dead targets. These results indicated that the patient's lymphocytes contained normal numbers of NK cells that were capable of recognizing and binding to a target but were incapable of killing the bound target cell. The patient's lymphocytes were then studied for their release of NKCF upon interaction with K562 cells. The patient's cells did not release NKCF, and the NK cell defect was not restored or improved by stimulation of the cells with IFN or IL 2. It is suggested that the deficient release of NKCF may have been related to the killing defect of the NK cells in this patient

  18. Use of lymphokine-activated killer cells to prevent bone marrow graft rejection and lethal graft-vs-host disease

    International Nuclear Information System (INIS)

    Azuma, E.; Yamamoto, H.; Kaplan, J.

    1989-01-01

    Prompted by our recent finding that lymphokine-activated killer (LAK) cells mediate both veto and natural suppression, we tested the ability of adoptively transferred LAK cells to block two in vivo alloreactions which complicate bone marrow transplantation: resistance to transplanted allogeneic bone marrow cells, and lethal graft-vs-host disease. Adoptive transfer of either donor type B6D2 or recipient-type B6 lymphokine-activated bone marrow cells, cells found to have strong LAK activity, abrogated or inhibited the resistance of irradiated B6 mice to both B6D2 marrow and third party-unrelated C3H marrow as measured by CFU in spleen on day 7. The ability of lymphokine-activated bone marrow cells to abrogate allogeneic resistance was eliminated by C lysis depletion of cells expressing asialo-GM1, NK1.1, and, to a variable degree, Thy-1, but not by depletion of cells expressing Lyt-2, indicating that the responsible cells had a LAK cell phenotype. Similar findings were obtained by using splenic LAK cells generated by 3 to 7 days of culture with rIL-2. Demonstration that allogeneic resistance could be blocked by a cloned LAK cell line provided direct evidence that LAK cells inhibit allogeneic resistance. In addition to inhibiting allogeneic resistance, adoptively transferred recipient-type LAK cells prevented lethal graft-vs-host disease, and permitted long term engraftment of allogeneic marrow. Irradiation prevented LAK cell inhibition of both allogeneic resistance and lethal graft-vs-host disease. These findings suggest that adoptive immunotherapy with LAK cells may prove useful in preventing graft rejection and graft-versus-host disease in human bone marrow transplant recipients

  19. Porphyromonas gingivalis as a Model Organism for Assessing Interaction of Anaerobic Bacteria with Host Cells.

    Science.gov (United States)

    Wunsch, Christopher M; Lewis, Janina P

    2015-12-17

    Anaerobic bacteria far outnumber aerobes in many human niches such as the gut, mouth, and vagina. Furthermore, anaerobic infections are common and frequently of indigenous origin. The ability of some anaerobic pathogens to invade human cells gives them adaptive measures to escape innate immunity as well as to modulate host cell behavior. However, ensuring that the anaerobic bacteria are live during experimental investigation of the events may pose challenges. Porphyromonas gingivalis, a Gram-negative anaerobe, is capable of invading a variety of eukaryotic non-phagocytic cells. This article outlines how to successfully culture and assess the ability of P. gingivalis to invade human umbilical vein endothelial cells (HUVECs). Two protocols were developed: one to measure bacteria that can successfully invade and survive within the host, and the other to visualize bacteria interacting with host cells. These techniques necessitate the use of an anaerobic chamber to supply P. gingivalis with an anaerobic environment for optimal growth. The first protocol is based on the antibiotic protection assay, which is largely used to study the invasion of host cells by bacteria. However, the antibiotic protection assay is limited; only intracellular bacteria that are culturable following antibiotic treatment and host cell lysis are measured. To assess all bacteria interacting with host cells, both live and dead, we developed a protocol that uses fluorescent microscopy to examine host-pathogen interaction. Bacteria are fluorescently labeled with 2',7'-Bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein acetoxymethyl ester (BCECF-AM) and used to infect eukaryotic cells under anaerobic conditions. Following fixing with paraformaldehyde and permeabilization with 0.2% Triton X-100, host cells are labeled with TRITC phalloidin and DAPI to label the cell cytoskeleton and nucleus, respectively. Multiple images taken at different focal points (Z-stack) are obtained for temporal

  20. Ultrasound-microbubble mediated cavitation of plant cells: effects on morphology and viability.

    Science.gov (United States)

    Qin, Peng; Xu, Lin; Zhong, Wenjing; Yu, Alfred C H

    2012-06-01

    The interaction between ultrasound pulses and microbubbles is known to generate acoustic cavitation that may puncture biological cells. This work presents new experimental findings on the bioeffects of ultrasound-microbubble mediated cavitation in plant cells with emphasis on direct observations of morphological impact and analysis of viability trends in tobacco BY-2 cells that are widely studied in higher plant physiology. The tobacco cell suspensions were exposed to 1 MHz ultrasound pulses in the presence of 1% v/v microbubbles (10% duty cycle; 1 kHz pulse repetition frequency; 70 mm between probe and cells; 1-min exposure time). Few bioeffects were observed at low peak negative pressures (cavitation presumably occurred. In contrast, at 0.9 MPa peak negative pressure (with more inertial cavitation activities according to our passive cavitation detection results), random pores were found on tobacco cell wall (observed via scanning electron microscopy) and enhanced exogenous uptake into the cytoplasm was evident (noted in our fluorescein isothiocyanate dextran uptake analysis). Also, instant lysis was observed in 23.4% of cells (found using trypan blue staining) and programmed cell death was seen in 23.3% of population after 12 h (determined by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling [TUNEL]). These bioeffects generally correspond in trend with those for mammalian cells. This raises the possibility of developing ultrasound-microbubble mediated cavitation into a targeted gene transfection paradigm for plant cells and, conversely, adopting plant cells as experimental test-beds for sonoporation-based gene therapy in mammalian cells. Copyright © 2012 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  1. Live attenuated measles virus vaccine therapy for locally established malignant glioblastoma tumor cells

    Directory of Open Access Journals (Sweden)

    Al-Shammari AM

    2014-05-01

    Full Text Available Ahmed M Al-Shammari,1 Farah E Ismaeel,2 Shahlaa M Salih,2 Nahi Y Yaseen11Experimental Therapy Department, Iraqi Center for Cancer and Medical Genetic Researches, Mustansiriya University, 2Departments of Biotechnology, College of Science, Al-Nahrain University, Baghdad, IraqAbstract: Glioblastoma multiforme is the most aggressive malignant primary brain tumor in humans, with poor prognosis. A new glioblastoma cell line (ANGM5 was established from a cerebral glioblastoma multiforme in a 72-year-old Iraqi man who underwent surgery for an intracranial tumor. This study was carried out to evaluate the antitumor effect of live attenuated measles virus (MV Schwarz vaccine strain on glioblastoma multiforme tumor cell lines in vitro. Live attenuated MV Schwarz strain was propagated on Vero, human rhabdomyosarcoma, and human glioblastoma-multiform (ANGM5 cell lines. The infected confluent monolayer appeared to be covered with syncytia with granulation and vacuolation, as well as cell rounding, shrinkage, and large empty space with cell debris as a result of cell lysis and death. Cell lines infected with virus have the ability for hemadsorption to human red blood cells after 72 hours of infection, whereas no hemadsorption of uninfected cells is seen. Detection of MV hemagglutinin protein by monoclonal antibodies in infected cells of all cell lines by immunocytochemistry assay gave positive results (brown color in the cytoplasm of infected cells. Cell viability was measured after 72 hours of infection by 3-(4,5-Dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide assay. Results showed a significant cytotoxic effect for MV (P≤0.05 on growth of ANGM5 and rhabdomyosarcoma cell lines after 72 hours of infection. Induction of apoptosis by MV was assessed by measuring mitochondrial membrane potentials in tumor cells after 48, 72, and 120 hours of infection. Apoptotic cells were counted, and the mean percentage of dead cells was significantly higher after 48, 72

  2. Screening of Chlamydomonas reinhardtii Populations with Single-Cell Resolution by Using a High-Throughput Microscale Sample Preparation for Matrix-Assisted Laser Desorption Ionization Mass Spectrometry.

    Science.gov (United States)

    Krismer, Jasmin; Sobek, Jens; Steinhoff, Robert F; Fagerer, Stephan R; Pabst, Martin; Zenobi, Renato

    2015-08-15

    The consequences of cellular heterogeneity, such as biocide persistence, can only be tackled by studying each individual in a cell population. Fluorescent tags provide tools for the high-throughput analysis of genomes, RNA transcripts, or proteins on the single-cell level. However, the analysis of lower-molecular-weight compounds that elude tagging is still a great challenge. Here, we describe a novel high-throughput microscale sample preparation technique for single cells that allows a mass spectrum to be obtained for each individual cell within a microbial population. The approach presented includes spotting Chlamydomonas reinhardtii cells, using a noncontact microarrayer, onto a specialized slide and controlled lysis of cells separated on the slide. Throughout the sample preparation, analytes were traced and individual steps optimized using autofluorescence detection of chlorophyll. The lysates of isolated cells are subjected to a direct, label-free analysis using matrix-assisted laser desorption ionization mass spectrometry. Thus, we were able to differentiate individual cells of two Chlamydomonas reinhardtii strains based on single-cell mass spectra. Furthermore, we showed that only population profiles with real single-cell resolution render a nondistorted picture of the phenotypes contained in a population. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  3. Cloning and chromosomal assignment of a human cDNA encoding a T cell- and natural killer cell-specific trypsin-like serine protease

    International Nuclear Information System (INIS)

    Gershenfeld, H.K.; Hershberger, R.J.; Shows, T.B.; Weissman, I.L.

    1988-01-01

    A cDNA clone encoding a human T cell- and natural killer cell-specific serine protease was obtained by screening a phage λgt10 cDNA library from phytohemagglutinin-stimulated human peripheral blood lymphocytes with the mouse Hanukah factor cDNA clone. In an RNA blot-hybridization analysis, this human Hanukah factor cDNA hybridized with a 1.3-kilobase band in allogeneic-stimulated cytotoxic T cells and the Jurkat cell line, but this transcript was not detectable in normal muscle, liver, tonsil, or thymus. By dot-blot hybridization, this cDNA hybridized with RNA from three cytolytic T-cell clones and three noncytolytic T-cell clones grown in vitro as well as with purified CD16 + natural killer cells and CD3 + , CD16 - T-cell large granular lymphocytes from peripheral blood lymphocytes (CD = cluster designation). The nucleotide sequence of this cDNA clone encodes a predicted serine protease of 262 amino acids. The active enzyme is 71% and 77% similar to the mouse sequence at the amino acid and DNA level, respectively. The human and mouse sequences conserve the active site residues of serine proteases--the trypsin-specific Asp-189 and all 10 cysteine residues. The gene for the human Hanukah factor serine protease is located on human chromosome 5. The authors propose that this trypsin-like serine protease may function as a common component necessary for lysis of target cells by cytotoxic T lymphocytes and natural killer cells

  4. Host Cell Responses to Persistent Mycoplasmas - Different Stages in Infection of HeLa Cells with Mycoplasma hominis

    Science.gov (United States)

    Hopfe, Miriam; Deenen, René; Degrandi, Daniel; Köhrer, Karl; Henrich, Birgit

    2013-01-01

    Mycoplasma hominis is a facultative human pathogen primarily associated with bacterial vaginosis and pelvic inflammatory disease, but it is also able to spread to other sites, leading to arthritis or, in neonates, meningitis. With a minimal set of 537 annotated genes, M. hominis is the second smallest self-replicating mycoplasma and thus an ideal model organism for studying the effects of an infectious agent on its host more closely. M. hominis adherence, colonisation and invasion of HeLa cells were characterised in a time-course study using scanning electron microscopy, confocal microscopy and microarray-based analysis of the HeLa cell transcriptome. At 4 h post infection, cytoadherence of M. hominis to the HeLa cell surface was accompanied by differential regulation of 723 host genes (>2 fold change in expression). Genes associated with immune responses and signal transduction pathways were mainly affected and components involved in cell-cycle regulation, growth and death were highly upregulated. At 48 h post infection, when mycoplasma invasion started, 1588 host genes were differentially expressed and expression of genes for lysosome-specific proteins associated with bacterial lysis was detected. In a chronically infected HeLa cell line (2 weeks), the proportion of intracellular mycoplasmas reached a maximum of 10% and M. hominis-filled protrusions of the host cell membrane were seen by confocal microscopy, suggesting exocytotic dissemination. Of the 1972 regulated host genes, components of the ECM-receptor interaction pathway and phagosome-related integrins were markedly increased. The immune response was quite different to that at the beginning of infection, with a prominent induction of IL1B gene expression, affecting pathways of MAPK signalling, and genes connected with cytokine-cytokine interactions and apoptosis. These data show for the first time the complex, time-dependent reaction of the host directed at mycoplasmal clearance and the counter measures of

  5. Oxidized low density lipoprotein induced caspase-1 mediated pyroptotic cell death in macrophages: implication in lesion instability?

    Directory of Open Access Journals (Sweden)

    Jing Lin

    Full Text Available BACKGROUND: Macrophage death in advanced lesion has been confirmed to play an important role in plaque instability. However, the mechanism underlying lesion macrophage death still remains largely unknown. METHODS AND RESULTS: Immunohistochemistry showed that caspase-1 activated in advanced lesion and co-located with macrophages and TUNEL positive reaction. In in-vitro experiments showed that ox-LDL induced caspase-1 activation and this activation was required for ox-LDL induced macrophages lysis, IL-1β and IL-18 production as well as DNA fragmentation. Mechanism experiments showed that CD36 and NLRP3/caspase-1/pathway involved in ox-LDL induced macrophage pyroptosis. CONCLUSION: Our study here identified a novel cell death, pyroptosis in ox-LDL induced human macrophage, which may be implicated in lesion macrophages death and play an important role in lesion instability.

  6. Production and purification of a soluble hydrogenase from Ralstonia eutropha H16 for potential hydrogen fuel cell applications.

    Science.gov (United States)

    Jugder, Bat-Erdene; Lebhar, Helene; Aguey-Zinsou, Kondo-Francois; Marquis, Christopher P

    2016-01-01

    The soluble hydrogenase (SH) from Ralstonia eutropha H16 is a promising candidate enzyme for H2-based biofuel application as it favours H2 oxidation and is relatively oxygen-tolerant. In this report, bioprocess development studies undertaken to produce and purify an active SH are described, based on the methods previously reported [1], [2], [3], [4]. Our modifications are: •Upstream method optimizations were undertaken on heterotrophic growth media and cell lysis involving ultrasonication.•Two anion exchangers (Q Sepharose and RESOURCE Q) and size exclusion chromatographic (Superdex 200) matrices were successfully employed for purification of a hexameric SH from R. eutropha.•The H2 oxidizing activity of the SH was demonstrated spectrophotometrically in solution and also immobilized on an EPG electrode using cyclic voltammetry.

  7. Identification and prevention of antibody disulfide bond reduction during cell culture manufacturing.

    Science.gov (United States)

    Trexler-Schmidt, Melody; Sargis, Sandy; Chiu, Jason; Sze-Khoo, Stefanie; Mun, Melissa; Kao, Yung-Hsiang; Laird, Michael W

    2010-06-15

    In the biopharmaceutical industry, therapeutic monoclonal antibodies are primarily produced in mammalian cell culture systems. During the scale-up of a monoclonal antibody production process, we observed excessive mechanical cell shear as well as significant reduction of the antibody's interchain disulfide bonds during harvest operations. This antibody reduction event was catastrophic as the product failed to meet the drug substance specifications and the bulk product was lost. Subsequent laboratory studies have demonstrated that cells subjected to mechanical shear release cellular enzymes that contribute to this antibody reduction phenomenon (manuscript submitted; Kao et al., 2009). Several methods to prevent this antibody reduction event were developed using a lab-scale model to reproduce the lysis and reduction events. These methods included modifications to the cell culture media with chemicals (e.g., cupric sulfate (CuSO(4))), pre- and post-harvest chemical additions to the cell culture fluid (CCF) (e.g., CuSO(4), EDTA, L-cystine), as well as lowering the pH and air sparging of the harvested CCF (HCCF). These methods were evaluated for their effectiveness in preventing disulfide bond reduction and their impact to product quality. Effective prevention methods, which yielded acceptable product quality were evaluated for their potential to be implemented at manufacturing-scale. The work described here identifies numerous effective reduction prevention measures from lab-scale studies; several of these methods were then successfully translated into manufacturing processes. 2010 Wiley Periodicals, Inc.

  8. Assembly of the T-cell antigen receptor. Participation of the CD3 omega chain

    DEFF Research Database (Denmark)

    Neisig, A; Vangsted, A; Zeuthen, J

    1993-01-01

    The human TCR is composed of the Ti alpha beta heterodimer in association with the CD3 chains CD3 gamma delta epsilon zeta 2. Another chain, referred to as CD3 omega, has recently been described in T cells. CD3 omega is an intracellular protein transiently associated with the CD3 complex during...... the assembly of the TCR in the endoplasmic reticulum (ER) and it is not expressed on the cell surface. The function of CD3 omega is unknown but it has been suggested that it plays an important role in the assembly of the TCR. We have studied the possible function of CD3 omega in the human leukemic T-cell line...... Jurkat and different variants of this cell line. Cells were metabolically labeled, subjected to lysis, immunoprecipitated, and analyzed by SDS-PAGE. The results indicate that: 1) CD3 omega associates primarily with the CD3 delta epsilon complex; 2) CD3 omega is not associated with single Ti alpha or Ti...

  9. Image-Based Single Cell Profiling: High-Throughput Processing of Mother Machine Experiments.

    Directory of Open Access Journals (Sweden)

    Christian Carsten Sachs

    Full Text Available Microfluidic lab-on-chip technology combined with live-cell imaging has enabled the observation of single cells in their spatio-temporal context. The mother machine (MM cultivation system is particularly attractive for the long-term investigation of rod-shaped bacteria since it facilitates continuous cultivation and observation of individual cells over many generations in a highly parallelized manner. To date, the lack of fully automated image analysis software limits the practical applicability of the MM as a phenotypic screening tool.We present an image analysis pipeline for the automated processing of MM time lapse image stacks. The pipeline supports all analysis steps, i.e., image registration, orientation correction, channel/cell detection, cell tracking, and result visualization. Tailored algorithms account for the specialized MM layout to enable a robust automated analysis. Image data generated in a two-day growth study (≈ 90 GB is analyzed in ≈ 30 min with negligible differences in growth rate between automated and manual evaluation quality. The proposed methods are implemented in the software molyso (MOther machine AnaLYsis SOftware that provides a new profiling tool to analyze unbiasedly hitherto inaccessible large-scale MM image stacks.Presented is the software molyso, a ready-to-use open source software (BSD-licensed for the unsupervised analysis of MM time-lapse image stacks. molyso source code and user manual are available at https://github.com/modsim/molyso.

  10. Molecular interactions of the combined effects of bleomycin and x-rays on mammalian cell survival

    International Nuclear Information System (INIS)

    Byfield, J.E.; Lee, Y.C.; Tu, L.; Kulhanian, F.

    1976-01-01

    The interactions between bleomycin and x-ray damage and repair have been examined in rat and human tumor cells. Bleomycin itself induces extensive DNA single-strand breaks but does not appear to inhibit the repair of x-ray-induced DNA single-strand breaks. Quantitative analysis of these interactions is complicated by the retention of active bleomycin within cells that remains capable of further DNA degradation even under the conditions of alkaline sucrose gradient cell lysis. DNA double-strand breaks and/or disruptions of DNA-lipid complexes also occur following bleomycin exposure. X-ray-induced excision repair replication is only minimally influenced by even high concentrations of bleomycin. A small amount of excision repair is demonstrable in nonirradiated cells treated with high concentrations of bleomycin consistent with repair of bleomycin-induced nucleotide damage in cellular DNA by a ''cut and patch'' repair mechanism. Repair of bleomycin-induced DNA single-strand breaks also occurs. The data indicate that bleomycin and x-ray damage are quite similar both in their induction and repair, but that lesions occur and are repaired independently. The enzymatic mechanisms appear similar in the two cell types despite substantial differences in their sensitivity to bleomycin

  11. Human platelet lysate: Replacing fetal bovine serum as a gold standard for human cell propagation?

    Science.gov (United States)

    Burnouf, Thierry; Strunk, Dirk; Koh, Mickey B C; Schallmoser, Katharina

    2016-01-01

    The essential physiological role of platelets in wound healing and tissue repair builds the rationale for the use of human platelet derivatives in regenerative medicine. Abundant growth factors and cytokines stored in platelet granules can be naturally released by thrombin activation and clotting or artificially by freeze/thaw-mediated platelet lysis, sonication or chemical treatment. Human platelet lysate prepared by the various release strategies has been established as a suitable alternative to fetal bovine serum as culture medium supplement, enabling efficient propagation of human cells under animal serum-free conditions for a multiplicity of applications in advanced somatic cell therapy and tissue engineering. The rapidly increasing number of studies using platelet derived products for inducing human cell proliferation and differentiation has also uncovered a considerable variability of human platelet lysate preparations which limits comparability of results. The main variations discussed herein encompass aspects of donor selection, preparation of the starting material, the possibility for pooling in plasma or additive solution, the implementation of pathogen inactivation and consideration of ABO blood groups, all of which can influence applicability. This review outlines the current knowledge about human platelet lysate as a powerful additive for human cell propagation and highlights its role as a prevailing supplement for human cell culture capable to replace animal serum in a growing spectrum of applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Proliferation and Differentiation of Autologic and Allogenic Stem Cells in Supralethally X-Irradiated Dogs

    Energy Technology Data Exchange (ETDEWEB)

    Chertkov, I. L. [Department of Radiobiology, Central Institute of Haematology and Blood Transfusion, Moscow, USSR (Russian Federation)

    1967-07-15

    Full text: Allogenic bone marrow after transplantation into dogs irradiated with 1000 R X-rays differentiates in the normal way only for 3-4 days, afterwards transforming into lymphoid cells. This transformation is due to the antigen stimulus of the host on the grafted stem cells. The lymphoid cells, obtained from the host's blood on the 7-8th day after grafting, showed specific, immune activity under the Immune Lymphocyte Transfer test. Within a short duration of the immune response immunoblasts and immunocytes Undergo degenerative changes: destroyed mitochondria, formation of autophagic vacuoles and, finally, lysis of the cells. These changes are suggested to be the result of overloading of immune cells with antigen. Preliminary sensitization of the donor with prospective host's haemopoietic tissue does not hasten the immune transformation of haemopoiesis. Injections of bacterial pyrogen, cortisone or 6-mercaptopurine into recipients, as well as incubation of bone marrow at 37 Degree-Sign C for 2 hours, do not prevent the immune transformation. Preliminary thymectomy of the prospective recipients prevents in some of the cases immune transformation of the bone-marrow graft. The delay of allogenic bone-marrow transplantation for 5-6 days prevents in some dogs (X-irradiated with 1000 R, but not with 1200 R) the immune transformation. Transplantation of autologic bone marrow or shielding of the legs during irradiation is accompanied with good restoration of normal haemopoiesis without lymphoid transformation. (author)

  13. Differentiation of B and T lymphocytes from precursor cells resident in the bone marrow

    Energy Technology Data Exchange (ETDEWEB)

    Rosse, C; Press, O W

    1978-01-01

    A series of experiments in guinea pigs and mice established that proliferating progenitor cells for B and T lymphocytes are a resident population in the bone marrow. It was shown by the combined use of /sup 3/H-TdR radioautography and fluorescent-antibody staining of B and T cells that the majority of bone marrow (BM) lymphocytes are rapidly renewed (RR) B cells and null cells, whereas the thymus (THY) consists overwhelming of RR T lymphocytes; in spleen (SPL) and lymph node (LN) slowly renewed (SR) T and B cells predominate. The rate of B cell turnover in guinea pig bone marrow exceeds that in the SPL or LN, and the appearance of newly generated B cells in the SPL lags behind that in the BM. When systematically administered /sup 3/H-TdR was excluded by tourniquets from tibial and femoral BM no labeled B cells appeared in tibial or femoral marrow over 72 h. When tibial and femoral BM was labeled selectively with /sup 3/H-TdR, labeled B cells appeared in the SPL and LN over 72 h. (It was found in CBA mice that BM cell fractions enriched in lymphocytes (BML) responded to the T cell mitogen PHA in a manner qualitatively different from the response of SPL and LN cells. Experiments with athymic nude mice and with complement-mediated lysis of T and B cells established that PHA responsive cells in SPL and LN were T cells but in BML they were null lymphocytes. Target cells of PHA in BML responded to the mitogen by the generation of T-cell surface markers and blastogenesis; therefore they were identified as pre-T cells. BM pre-T cells are rapidly renewed and, in contrast to PHA responsive cells of SPL and LN, do not recirculate from blood to lymph. Both B and pre-T cells in the BM are division products of transitional cells. Among transitional cells of the marrow are included the progenitors of B and T lmyphhocytes and of all other types of hemopoietic cells.

  14. Structure of the T cell receptor in a Ti alpha V beta 2, alpha V beta 8-positive T cell line

    DEFF Research Database (Denmark)

    Hou, X; Dietrich, J; Kuhlmann, J

    1994-01-01

    not known; however, it has been suggested that each TcR contains two Ti dimers. To gain insight into the structure of the TcR we constructed a Ti alpha V beta 2, alpha V beta 8-positive T cell line which expressed the endogenous human TiV beta 8 and the transfected mouse TiV beta 2 both in association......The T cell receptor (TcR) is composed of at least six different polypeptide chains consisting of the clonotypic Ti heterodimer (Ti alpha beta or Ti gamma delta) and the noncovalently associated CD3 chains (CD3 gamma delta epsilon zeta). The exact number of subunits constituting the TcR is still...... with the endogenous Ti alpha and CD3 chains at the cell surface. Preclearing experiments with radioiodinated cell lysate prepared with digitonin lysis buffer demonstrated that depleting the lysate of Ti alpha V beta 8 by immunoprecipitation with anti V beta 8 monoclonal antibody (mAb) did not reduce the amount of Ti...

  15. Single-cell analysis of pyroptosis dynamics reveals conserved GSDMD-mediated subcellular events that precede plasma membrane rupture.

    Science.gov (United States)

    de Vasconcelos, Nathalia M; Van Opdenbosch, Nina; Van Gorp, Hanne; Parthoens, Eef; Lamkanfi, Mohamed

    2018-04-17

    Pyroptosis is rapidly emerging as a mechanism of anti-microbial host defense, and of extracellular release of the inflammasome-dependent cytokines interleukin (IL)-1β and IL-18, which contributes to autoinflammatory pathology. Caspases 1, 4, 5 and 11 trigger this regulated form of necrosis by cleaving the pyroptosis effector gasdermin D (GSDMD), causing its pore-forming amino-terminal domain to oligomerize and perforate the plasma membrane. However, the subcellular events that precede pyroptotic cell lysis are ill defined. In this study, we triggered primary macrophages to undergo pyroptosis from three inflammasome types and recorded their dynamics and morphology using high-resolution live-cell spinning disk confocal laser microscopy. Based on quantitative analysis of single-cell subcellular events, we propose a model of pyroptotic cell disintegration that is initiated by opening of GSDMD-dependent ion channels or pores that are more restrictive than recently proposed GSDMD pores, followed by osmotic cell swelling, commitment of mitochondria and other membrane-bound organelles prior to sudden rupture of the plasma membrane and full permeability to intracellular proteins. This study provides a dynamic framework for understanding cellular changes that occur during pyroptosis, and charts a chronological sequence of GSDMD-mediated subcellular events that define pyroptotic cell death at the single-cell level.

  16. The small protein MbiA interacts with MreB and modulates cell shape in Caulobacter crescentus.

    Science.gov (United States)

    Yakhnina, Anastasiya A; Gitai, Zemer

    2012-09-01

    In Caulobacter crescentus, the actin homologue MreB is critical for cell shape maintenance. Despite the central importance of MreB for cell morphology and viability, very little is known about MreB-interacting factors. Here, we use an overexpression approach to identify a novel MreB interactor, MbiA. MbiA interacts with MreB in both biochemical and genetic assays, colocalizes with MreB throughout the cell cycle, and relies on MreB for its localization. MbiA overexpression mimics the loss of MreB function, severely perturbing cell morphology, inhibiting growth and inducing cell lysis. Additionally, mbiA deletion shows a synthetic growth phenotype with a hypomorphic allele of the MreB interactor RodZ, suggesting that these two MreB-interacting proteins either have partially redundant functions or participate in the same functional complex. Our work thus establishes MbiA as a novel cell shape regulator that appears to function through regulating MreB, and opens avenues for discovery of more MreB-regulating factors by showing that overexpression screens are a valuable tool for uncovering potentially redundant cell shape effectors. © 2012 Blackwell Publishing Ltd.

  17. Adaptive T cell responses induced by oncolytic Herpes Simplex Virus-granulocyte macrophage-colony-stimulating factor therapy expanded by dendritic cell and cytokine-induced killer cell adoptive therapy.

    Science.gov (United States)

    Ren, Jun; Gwin, William R; Zhou, Xinna; Wang, Xiaoli; Huang, Hongyan; Jiang, Ni; Zhou, Lei; Agarwal, Pankaj; Hobeika, Amy; Crosby, Erika; Hartman, Zachary C; Morse, Michael A; H Eng, Kevin; Lyerly, H Kim

    2017-01-01

    Purpose : Although local oncolytic viral therapy (OVT) may enhance tumor lysis, antigen release, and adaptive immune responses, systemic antitumor responses post-therapy are limited. Adoptive immunotherapy with autologous dendritic cells (DC) and cytokine-induced killer cells (DC-CIK) synergizes with systemic therapies. We hypothesized that OVT with Herpes Simplex Virus-granulocyte macrophage-colony-stimulating factor (HSV-GM-CSF) would induce adaptive T cell responses that could be expanded systemically with sequential DC-CIK therapy. Patients and Methods : We performed a pilot study of intratumoral HSV-GM-CSF OVT followed by autologous DC-CIK cell therapy. In addition to safety and clinical endpoints, we monitored adaptive T cell responses by quantifying T cell receptor (TCR) populations in pre-oncolytic therapy, post-oncolytic therapy, and after DC-CIK therapy. Results : Nine patients with advanced malignancy were treated with OVT (OrienX010), of whom seven experienced stable disease (SD). Five of the OVT treated patients underwent leukapheresis, generation, and delivery of DC-CIKs, and two had SD, whereas three progressed. T cell receptor sequencing of TCR β sequences one month after OVT therapy demonstrates a dynamic TCR repertoire in response to OVT therapy in the majority of patients with the systematic expansion of multiple T cell clone populations following DC-CIK therapy. This treatment was well tolerated and long-term event free and overall survival was observed in six of the nine patients. Conclusions : Strategies inducing the local activation of tumor-specific immune responses can be combined with adoptive cellular therapies to expand the adaptive T cell responses systemically and further studies are warranted.

  18. CD8 T cells protect adult naive mice from JEV-induced morbidity via lytic function.

    Science.gov (United States)

    Jain, Nidhi; Oswal, Neelam; Chawla, Amanpreet Singh; Agrawal, Tanvi; Biswas, Moanaro; Vrati, Sudhanshu; Rath, Satyajit; George, Anna; Bal, Vineeta; Medigeshi, Guruprasad R

    2017-02-01

    Following Japanese encephalitis virus (JEV) infection neutralizing antibodies are shown to provide protection in a significant proportion of cases, but not all, suggesting additional components of immune system might also contribute to elicit protective immune response. Here we have characterized the role of T cells in offering protection in adult mice infected with JEV. Mice lacking α/β-T cells (TCRβ-null) are highly susceptible and die over 10-18 day period as compared to the wild-type (WT) mice which are resistant. This is associated with high viral load, higher mRNA levels of proinflammatory cytokines and breach in the blood-brain-barrier (BBB). Infected WT mice do not show a breach in BBB; however, in contrast to TCRβ-null, they show the presence of T cells in the brain. Using adoptive transfer of cells with specific genetic deficiencies we see that neither the presence of CD4 T cells nor cytokines such as IL-4, IL-10 or interferon-gamma have any significant role in offering protection from primary infection. In contrast, we show that CD8 T cell deficiency is more critical as absence of CD8 T cells alone increases mortality in mice infected with JEV. Further, transfer of T cells from beige mice with defects in granular lytic function into TCRβ-null mice shows poor protection implicating granule-mediated target cell lysis as an essential component for survival. In addition, for the first time we report that γ/δ-T cells also make significant contribution to confer protection from JEV infection. Our data show that effector CD8 T cells play a protective role during primary infection possibly by preventing the breach in BBB and neuronal damage.

  19. CD8 T cells protect adult naive mice from JEV-induced morbidity via lytic function.

    Directory of Open Access Journals (Sweden)

    Nidhi Jain

    2017-02-01

    Full Text Available Following Japanese encephalitis virus (JEV infection neutralizing antibodies are shown to provide protection in a significant proportion of cases, but not all, suggesting additional components of immune system might also contribute to elicit protective immune response. Here we have characterized the role of T cells in offering protection in adult mice infected with JEV. Mice lacking α/β-T cells (TCRβ-null are highly susceptible and die over 10-18 day period as compared to the wild-type (WT mice which are resistant. This is associated with high viral load, higher mRNA levels of proinflammatory cytokines and breach in the blood-brain-barrier (BBB. Infected WT mice do not show a breach in BBB; however, in contrast to TCRβ-null, they show the presence of T cells in the brain. Using adoptive transfer of cells with specific genetic deficiencies we see that neither the presence of CD4 T cells nor cytokines such as IL-4, IL-10 or interferon-gamma have any significant role in offering protection from primary infection. In contrast, we show that CD8 T cell deficiency is more critical as absence of CD8 T cells alone increases mortality in mice infected with JEV. Further, transfer of T cells from beige mice with defects in granular lytic function into TCRβ-null mice shows poor protection implicating granule-mediated target cell lysis as an essential component for survival. In addition, for the first time we report that γ/δ-T cells also make significant contribution to confer protection from JEV infection. Our data show that effector CD8 T cells play a protective role during primary infection possibly by preventing the breach in BBB and neuronal damage.

  20. Cell death and autophagy: Cytokines, drugs, and nutritional factors

    International Nuclear Information System (INIS)

    Bursch, Wilfried; Karwan, Anneliese; Mayer, Miriam; Dornetshuber, Julia; Froehwein, Ulrike; Schulte-Hermann, Rolf; Fazi, Barbara; Di Sano, Federica; Piredda, Lucia; Piacentini, Mauro; Petrovski, Goran; Fesues, Laszlo; Gerner, Christopher

    2008-01-01

    Cells may use multiple pathways to commit suicide. In certain contexts, dying cells generate large amounts of autophagic vacuoles and clear large proportions of their cytoplasm, before they finally die, as exemplified by the treatment of human mammary carcinoma cells with the anti-estrogen tamoxifen (TAM, ≤1 μM). Protein analysis during autophagic cell death revealed distinct proteins of the nuclear fraction including GST-π and some proteasomal subunit constituents to be affected during autophagic cell death. Depending on the functional status of caspase-3, MCF-7 cells may switch between autophagic and apoptotic features of cell death [Fazi, B., Bursch, W., Fimia, G.M., Nardacci R., Piacentini, M., Di Sano, F., Piredda, L., 2008. Fenretinide induces autophagic cell death in caspase-defective breast cancer cells. Autophagy 4(4), 435-441]. Furthermore, the self-destruction of MCF-7 cells was found to be completed by phagocytosis of cell residues [Petrovski, G., Zahuczky, G., Katona, K., Vereb, G., Martinet, W., Nemes, Z., Bursch, W., Fesues, L., 2007. Clearance of dying autophagic cells of different origin by professional and non-professional phagocytes. Cell Death Diff. 14 (6), 1117-1128]. Autophagy also constitutes a cell's strategy of defense upon cell damage by eliminating damaged bulk proteins/organelles. This biological condition may be exemplified by the treatment of MCF-7 cells with a necrogenic TAM-dose (10 μM), resulting in the lysis of almost all cells within 24 h. However, a transient (1 h) challenge of MCF-7 cells with the same dose allowed the recovery of cells involving autophagy. Enrichment of chaperones in the insoluble cytoplasmic protein fraction indicated the formation of aggresomes, a potential trigger for autophagy. In a further experimental model HL60 cells were treated with TAM, causing dose-dependent distinct responses: 1-5 μM TAM, autophagy predominant; 7-9 μM, apoptosis predominant; 15 μM, necrosis. These phenomena might be

  1. Calpain expression and activity during lens fiber cell differentiation.

    Science.gov (United States)

    De Maria, Alicia; Shi, Yanrong; Kumar, Nalin M; Bassnett, Steven

    2009-05-15

    In animal models, the dysregulated activity of calcium-activated proteases, calpains, contributes directly to cataract formation. However, the physiological role of calpains in the healthy lens is not well defined. In this study, we examined the expression pattern of calpains in the mouse lens. Real time PCR and Western blotting data indicated that calpain 1, 2, 3, and 7 were expressed in lens fiber cells. Using controlled lysis, depth-dependent expression profiles for each calpain were obtained. These indicated that, unlike calpain 1, 2, and 7, which were most abundant in cells near the lens surface, calpain 3 expression was strongest in the deep cortical region of the lens. We detected calpain activities in vitro and showed that calpains were active in vivo by microinjecting fluorogenic calpain substrates into cortical fiber cells. To identify endogenous calpain substrates, membrane/cytoskeleton preparations were treated with recombinant calpain, and cleaved products were identified by two-dimensional difference electrophoresis/mass spectrometry. Among the calpain substrates identified by this approach was alphaII-spectrin. An antibody that specifically recognized calpain-cleaved spectrin was used to demonstrate that spectrin is cleaved in vivo, late in fiber cell differentiation, at or about the time that lens organelles are degraded. The generation of the calpain-specific spectrin cleavage product was not observed in lens tissue from calpain 3-null mice, indicating that calpain 3 is uniquely activated during lens fiber differentiation. Our data suggest a role for calpains in the remodeling of the membrane cytoskeleton that occurs with fiber cell maturation.

  2. A novel murine T-cell receptor targeting NY-ESO-1.

    Science.gov (United States)

    Rosati, Shannon F; Parkhurst, Maria R; Hong, Young; Zheng, Zhili; Feldman, Steven A; Rao, Mahadev; Abate-Daga, Daniel; Beard, Rachel E; Xu, Hui; Black, Mary A; Robbins, Paul F; Schrump, David A; Rosenberg, Steven A; Morgan, Richard A

    2014-04-01

    Cancer testis antigens, such as NY-ESO-1, are expressed in a variety of prevalent tumors and represent potential targets for T-cell receptor (TCR) gene therapy. DNA encoding a murine anti-NY-ESO-1 TCR gene (mTCR) was isolated from immunized HLA-A*0201 transgenic mice and inserted into a γ-retroviral vector. Two mTCR vectors were produced and used to transduce human PBL. Transduced cells were cocultured with tumor target cell lines and T2 cells pulsed with the NY-ESO-1 peptide, and assayed for cytokine release and cell lysis activity. The most active TCR construct was selected for production of a master cell bank for clinical use. mTCR-transduced PBL maintained TCR expression in short-term and long-term culture, ranging from 50% to 90% efficiency 7-11 days after stimulation and 46%-82% 10-20 days after restimulation. High levels of interferon-γ secretion were observed (1000-12000 pg/mL), in tumor coculture assays and recognition of peptide-pulsed cells was observed at 0.1 ng/mL, suggesting that the new mTCR had high avidity for antigen recognition. mTCR-transduced T cells also specifically lysed human tumor targets. In all assays, the mTCR was equivalent or better than the comparable human TCR. As the functional activity of TCR-transduced cells may be affected by the formation of mixed dimers, mTCRs, which are less likely to form mixed dimers with endogenous hTCRs, may be more effective in vivo. This new mTCR targeted to NY-ESO-1 represents a novel potential therapeutic option for adoptive cell-transfer therapy for a variety of malignancies.

  3. Fully synthetic phage-like system for screening mixtures of small molecules in live cells.

    Science.gov (United States)

    Byk, Gerardo; Partouche, Shirly; Weiss, Aryeh; Margel, Shlomo; Khandadash, Raz

    2010-05-10

    A synthetic "phage-like" system was designed for screening mixtures of small molecules in live cells. The core of the system consists of 2 mum diameter cross-linked monodispersed microspheres bearing a panel of fluorescent tags and peptides or small molecules either directly synthesized or covalently conjugated to the microspheres. The microsphere mixtures were screened for affinity to cell line PC-3 (prostate cancer model) by incubation with live cells, and as was with phage-display peptide methods, unbound microspheres were removed by repeated washings followed by total lysis of cells and analysis of the bound microspheres by flow-cytometry. Similar to phage-display peptide screening, this method can be applied even in the absence of prior information about the cellular targets of the candidate ligands, which makes the system especially interesting for selection of molecules with high affinity for desired cells, tissues, or tumors. The advantage of the proposed system is the possibility of screening synthetic non-natural peptides or small molecules that cannot be expressed and screened using phage display libraries. A library composed of small molecules synthesized by the Ugi reaction was screened, and a small molecule, Rak-2, which strongly binds to PC-3 cells was found. Rak-2 was then individually synthesized and validated in a complementary whole cell-based binding assay, as well as by live cell microscopy. This new system demonstrates that a mixture of molecules bound to subcellular sized microspheres can be screened on plated cells. Together with other methods using subcellular sized particles for cellular multiplexing, this method represents an important milestone toward high throughput screening of mixtures of small molecules in live cells and in vivo with potential applications in the fields of drug delivery and diagnostic imaging.

  4. Human Cytotoxic T Lymphocytes Form Dysfunctional Immune Synapses with B Cells Characterized by Non-Polarized Lytic Granule Release

    Directory of Open Access Journals (Sweden)

    Anna Kabanova

    2016-04-01

    Full Text Available Suppression of the cytotoxic T cell (CTL immune response has been proposed as one mechanism for immune evasion in cancer. In this study, we have explored the underlying basis for CTL suppression in the context of B cell malignancies. We document that human B cells have an intrinsic ability to resist killing by freshly isolated cytotoxic T cells (CTLs, but are susceptible to lysis by IL-2 activated CTL blasts and CTLs isolated from immunotherapy-treated patients with chronic lymphocytic leukemia (CLL. Impaired killing was associated with the formation of dysfunctional non-lytic immune synapses characterized by the presence of defective linker for activation of T cells (LAT signaling and non-polarized release of the lytic granules transported by ADP-ribosylation factor-like protein 8 (Arl8. We propose that non-lytic degranulation of CTLs are a key regulatory mechanism of evasion through which B cells may interfere with the formation of functional immune synapses by CTLs.

  5. Acute radiation effects on the content and release of plasminogen activator activity in cultured aortic endothelial cells

    International Nuclear Information System (INIS)

    Ts'ao, C.H.; Ward, W.F.

    1985-01-01

    Confluent monolayers from three lines of bovine aortic endothelial cells were exposed to a single dose of 10 Gy of 60 Co γ rays. Seventy-two hours later, the morphology of the irradiated and sham-irradiated monolayers was examined, and cellular DNA and protein contents were determined. In addition, the release of plasminogen activator (PA) activity int