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Sample records for bimolecular fluorescence complementation

  1. Use of bimolecular fluorescence complementation in yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Skarp, Kari-Pekka; Zhao, Xueqiang; Weber, Marion; Jantti, Jussi

    2008-01-01

    Visualization of protein-protein interactions in vivo offers a powerful tool to resolve spatial and temporal aspects of cellular functions. Bimolecular fluorescence complementation (BiFC) makes use of nonfluorescent fragments of green fluorescent protein or its variants that are added as "tags" to target proteins under study. Only upon target protein interaction is a fluorescent protein complex assembled and the site of interaction can be monitored by microscopy. In this chapter, we describe the method and tools for use of BiFC in the yeast Saccharomyces cerevisiae. PMID:19066026

  2. An improved bimolecular fluorescence complementation tool based on superfolder green fluorescent protein

    Institute of Scientific and Technical Information of China (English)

    Jun Zhou; Jian Lin; Cuihong Zhou; Xiaoyan Deng; Bin Xia

    2011-01-01

    Bimolecular fluorescence complementation (BiFC) has been widely used in the analysis of protein-protein interactions (PPIs) in recent years. There are many notable advantages of BiFC such as convenience and direct visualization of PPI in cells. However, BiFC has one common limitation: the separated non-fluorescent fragments can be spontaneously self-assembled into an intact protein,which leads to false-positive results. In this study, a pair of complementary fragments (sfGFPN and sfGFPC) was constructed by splitting superfolder GFP (sfGFP) between the 214 and 215 amino acid residue, and sfGFPC was mutated by site-directed gene mutagenesis to decrease the signal of negative control. Our results showed that mutations in sfGFPC (sfGFPC(m12)) can effectively decrease the signal of negative control. Thus, we provide an improved BiFC tool for the analysis of PPI. Further,since the self-assembly problem is a common shortcoming for application of BiFC, our research provides a feasible strategy for other BiFC candidate proteins with the same problem.

  3. Bimolecular Fluorescence Complementation to Assay the Interactions of Ubiquitylation Enzymes in Living Yeast Cells.

    Science.gov (United States)

    Blaszczak, Ewa; Prigent, Claude; Rabut, Gwenaël

    2016-01-01

    Ubiquitylation is a versatile posttranslational protein modification catalyzed through the concerted action of ubiquitin-conjugating enzymes (E2s) and ubiquitin ligases (E3s). These enzymes form transient complexes with each other and their modification substrates and determine the nature of the ubiquitin signals attached to their substrates. One challenge in the field of protein ubiquitylation is thus to identify the E2-E3 pairs that function in the cell. In this chapter, we describe the use of bimolecular fluorescence complementation to assay E2-E3 interactions in living cells, using budding yeast as a model organism. PMID:27613039

  4. Analysis of the papillomavirus E2 and bromodomain protein Brd4 interaction using bimolecular fluorescence complementation.

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    Christine M Helfer

    Full Text Available The human papillomavirus (HPV vaccines effectively protect against new infections of up to four HPV subtypes. However, these vaccines are not protective against many other clinically relevant HPV subtypes and are ineffective at treating established HPV infections. There is therefore a significant need for antiviral treatments for persistent HPV infections. A promising anti-HPV drug target is the interaction between the HPV E2 protein and cellular bromodomain-containing protein 4 (Brd4 since this protein complex mediates several processes important for the viral life cycle including viral genome maintenance, replication, and transcription. Using bimolecular fluorescence complementation (BiFC technology, we demonstrate the E2 and Brd4 interaction on both interphase chromatin and mitotic chromosomes throughout mitosis. The E2-Brd4 BiFC was significantly diminished by mutating the Brd4 binding sites in E2 or by a dominant negative inhibitor of the E2-Brd4 interaction, demonstrating the potential of BiFC for identifying inhibitors of this important virus-host interaction. Importantly, when Brd4 was released from chromatin using the bromodomain inhibitor JQ1(+, the E2-Brd4 interacting complex relocated into foci that no longer associate with mitotic chromosomes, pointing to JQ1(+ as a promising antiviral inhibitor of HPV genome maintenance during HPV persistent infection.

  5. Visualization of protein interactions in living Drosophila embryos by the bimolecular fluorescence complementation assay

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    Merabet Samir

    2011-01-01

    Full Text Available Abstract Background Protein interactions control the regulatory networks underlying developmental processes. The understanding of developmental complexity will, therefore, require the characterization of protein interactions within their proper environment. The bimolecular fluorescence complementation (BiFC technology offers this possibility as it enables the direct visualization of protein interactions in living cells. However, its potential has rarely been applied in embryos of animal model organisms and was only performed under transient protein expression levels. Results Using a Hox protein partnership as a test case, we investigated the suitability of BiFC for the study of protein interactions in the living Drosophila embryo. Importantly, all BiFC parameters were established with constructs that were stably expressed under the control of endogenous promoters. Under these physiological conditions, we showed that BiFC is specific and sensitive enough to analyse dynamic protein interactions. We next used BiFC in a candidate interaction screen, which led to the identification of several Hox protein partners. Conclusion Our results establish the general suitability of BiFC for revealing and studying protein interactions in their physiological context during the rapid course of Drosophila embryonic development.

  6. Viral bimolecular fluorescence complementation: a novel tool to study intracellular vesicular trafficking pathways.

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    Brennan S Dirk

    Full Text Available The Human Immunodeficiency Virus type 1 (HIV-1 accessory protein Nef interacts with a multitude of cellular proteins, manipulating the host membrane trafficking machinery to evade immune surveillance. Nef interactions have been analyzed using various in vitro assays, co-immunoprecipitation studies, and more recently mass spectrometry. However, these methods do not evaluate Nef interactions in the context of viral infection nor do they define the sub-cellular location of these interactions. In this report, we describe a novel bimolecular fluorescence complementation (BiFC lentiviral expression tool, termed viral BiFC, to study Nef interactions with host cellular proteins in the context of viral infection. Using the F2A cleavage site from the foot and mouth disease virus we generated a viral BiFC expression vector capable of concurrent expression of Nef and host cellular proteins; PACS-1, MHC-I and SNX18. Our studies confirmed the interaction between Nef and PACS-1, a host membrane trafficking protein involved in Nef-mediated immune evasion, and demonstrated co-localization of this complex with LAMP-1 positive endolysosomal vesicles. Furthermore, we utilized viral BiFC to localize the Nef/MHC-I interaction to an AP-1 positive endosomal compartment. Finally, viral BiFC was observed between Nef and the membrane trafficking regulator SNX18. This novel demonstration of an association between Nef and SNX18 was localized to AP-1 positive vesicles. In summary, viral BiFC is a unique tool designed to analyze the interaction between Nef and host cellular proteins by mapping the sub-cellular locations of their interactions during viral infection.

  7. Bimolecular Fluorescence Complementation (BiFC) Analysis of Protein-Protein Interactions and Assessment of Subcellular Localization in Live Cells.

    Science.gov (United States)

    Pratt, Evan P S; Owens, Jake L; Hockerman, Gregory H; Hu, Chang-Deng

    2016-01-01

    Bimolecular fluorescence complementation (BiFC) is a fluorescence imaging technique used to visualize protein-protein interactions (PPIs) in live cells and animals. One unique application of BiFC is to reveal subcellular localization of PPIs. The superior signal-to-noise ratio of BiFC in comparison with fluorescence resonance energy transfer or bioluminescence resonance energy transfer enables its wide applications. Here, we describe how confocal microscopy can be used to detect and quantify PPIs and their subcellular localization. We use basic leucine zipper transcription factor proteins as an example to provide a step-by-step BiFC protocol using a Nikon A1 confocal microscope and NIS-Elements imaging software. The protocol given below can be readily adapted for use with other confocal microscopes or imaging software. PMID:27515079

  8. Lighting the Way to Protein-Protein Interactions: Recommendations on Best Practices for Bimolecular Fluorescence Complementation Analyses[OPEN

    Science.gov (United States)

    Kudla, Jörg

    2016-01-01

    Techniques to detect and verify interactions between proteins in vivo have become invaluable tools in functional genomic research. While many of the initially developed interaction assays (e.g., yeast two-hybrid system and split-ubiquitin assay) usually are conducted in heterologous systems, assays relying on bimolecular fluorescence complementation (BiFC; also referred to as split-YFP assays) are applicable to the analysis of protein-protein interactions in most native systems, including plant cells. Like all protein-protein interaction assays, BiFC can produce false positive and false negative results. The purpose of this commentary is to (1) highlight shortcomings of and potential pitfalls in BiFC assays, (2) provide guidelines for avoiding artifactual interactions, and (3) suggest suitable approaches to scrutinize potential interactions and validate them by independent methods. PMID:27099259

  9. Characterization of the latent membrane protein 1 signaling complex of Epstein-Barr virus in the membrane of mammalian cells with bimolecular fluorescence complementation

    OpenAIRE

    Everly David N; Emery Amanda; Talaty Pooja

    2011-01-01

    Abstract Background Bimolecular fluorescence complementation (BiFC) is a novel technique to examine protein-protein interaction through the assembly of fluorescent proteins. In the present study, BiFC was used to study the assembly of the Epstein-Barr virus latent membrane protein 1 (LMP1) signaling complex within the membrane of mammalian cells. LMP1 signaling requires oligomerization, localization to lipid rafts, and association of the cytoplasmic domain to adaptor proteins, such as the tum...

  10. Bimolecular Fluorescence Complementation (BiFC) Assay for Direct Visualization of Protein-Protein Interaction in vivo

    Science.gov (United States)

    Lai, Hsien-Tsung; Chiang, Cheng-Ming

    2016-01-01

    Bimolecular Fluorescence Complementation (BiFC) assay is a method used to directly visualize protein-protein interaction in vivo using live-cell imaging or fixed cells. This protocol described here is based on our recent paper describing the functional association of human chromatin adaptor and transcription cofactor Brd4 with p53 tumor suppressor protein (Wu et al., 2013). BiFC was first described by Hu et al. (2002) using two non-fluorescent protein fragments of enhanced yellow fluorescent protein (EYFP), which is an Aequorea victoria GFP variant protein, fused respectively to a Rel family protein and a bZIP family transcription factor to investigate interactions between these two family members in living cells. The YFP was later improved by introducing mutations to reduce its sensitivity to pH and chloride ions, thus generating a super-enhanced YFP, named Venus fluorescent protein, without showing diminished fluorescence at 37 °C as typically observed with EYFP (Nagai et al., 2006). The fluorescence signal is regenerated by complementation of two non-fluorescent fragments (e.g., the Venus N-terminal 1–158 amino acid residues, called Venus-N, and its C-terminal 159–239 amino acid residues, named Venus-C; see Figure 1A and Gully et al., 2012; Ding et al., 2006; Kerppola, 2006) that are brought together by interaction between their respective fusion partners (e.g., Venus-N to p53, and Venus-C to the PDID domain of human Brd4; see Figure 1B and 1C). The intensity and cellular location of the regenerated fluorescence signals can be detected by fluorescence microscope. The advantages of the proximity-based BiFC assay are: first, it allows a direct visualization of spatial and temporal interaction between two partner proteins in vivo; second, the fluorescence signal provides a sensitive readout for detecting protein-protein interaction even at a low expression level comparable to that of the endogenous proteins; third, the intensity of the fluorescence signal is

  11. Vectors for multi-color bimolecular fluorescence complementation to investigate protein-protein interactions in living plant cells

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    Kuang Lin-Yun

    2008-10-01

    Full Text Available Abstract Background The investigation of protein-protein interactions is important for characterizing protein function. Bimolecular fluorescence complementation (BiFC has recently gained interest as a relatively easy and inexpensive method to visualize protein-protein interactions in living cells. BiFC uses "split YFP" tags on proteins to detect interactions: If the tagged proteins interact, they may bring the two split fluorophore components together such that they can fold and reconstitute fluorescence. The sites of interaction can be monitored using epifluorescence or confocal microscopy. However, "conventional" BiFC can investigate interactions only between two proteins at a time. There are instances when one may wish to offer a particular "bait" protein to several "prey" proteins simultaneously. Preferential interaction of the bait protein with one of the prey proteins, or different sites of interaction between the bait protein and multiple prey proteins, may thus be observed. Results We have constructed a series of gene expression vectors, based upon the pSAT series of vectors, to facilitate the practice of multi-color BiFC. The bait protein is tagged with the C-terminal portion of CFP (cCFP, and prey proteins are tagged with the N-terminal portions of either Venus (nVenus or Cerulean (nCerulean. Interaction of cCFP-tagged proteins with nVenus-tagged proteins generates yellow fluorescence, whereas interaction of cCFP-tagged proteins with nCerulean-tagged proteins generates blue fluorescence. Additional expression of mCherry indicates transfected cells and sub-cellular structures. Using this system, we have determined in both tobacco BY-2 protoplasts and in onion epidermal cells that Agrobacterium VirE2 protein interacts with the Arabidopsis nuclear transport adapter protein importin α-1 in the cytoplasm, whereas interaction of VirE2 with a different importin α isoform, importin α-4, occurs predominantly in the nucleus. Conclusion Multi

  12. Characterization of the latent membrane protein 1 signaling complex of Epstein-Barr virus in the membrane of mammalian cells with bimolecular fluorescence complementation

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    Everly David N

    2011-08-01

    Full Text Available Abstract Background Bimolecular fluorescence complementation (BiFC is a novel technique to examine protein-protein interaction through the assembly of fluorescent proteins. In the present study, BiFC was used to study the assembly of the Epstein-Barr virus latent membrane protein 1 (LMP1 signaling complex within the membrane of mammalian cells. LMP1 signaling requires oligomerization, localization to lipid rafts, and association of the cytoplasmic domain to adaptor proteins, such as the tumor necrosis factor receptor associated factors (TRAFs. Methods LMP1-TRAF and LMP1-LMP1 interactions were assayed by BiFC using fluorescence microscopy and flow cytometry. Function of LMP1 BiFC contructs were confirmed by transformation assays and nuclear factor- κB (NF-κB reporter assays. Results BiFC was observed between LMP1 and TRAF2 or TRAF3 and mutation of the LMP1 signaling domains reduced complementation. Fluorescence was observed in previously described LMP1 signaling locations. Oligomerization of LMP1 with itself induced complementation and BiFC. LMP1-BiFC constructs were fully functional in rodent fibroblast transformation assays and activation of NF-κB reporter activity. The BiFC domain partially suppressed some LMP1 mutant phenotypes. Conclusions Together these data suggest that BiFC is a unique and novel platform to identify and characterize proteins recruited to the LMP1-signaling complex.

  13. Identification of transmembrane protein 134 as a novel LMP1-binding protein by using bimolecular fluorescence complementation and an enhanced retroviral mutagen.

    Science.gov (United States)

    Talaty, Pooja; Emery, Amanda; Holthusen, Kirsten; Everly, David N

    2012-10-01

    Latent membrane protein 1 (LMP1) of Epstein-Barr virus induces constitutive signaling in infected cells. LMP1 signaling requires oligomerization of LMP1 via its transmembrane domain, localization to lipid rafts in the membrane, and association of the LMP1 cytoplasmic domain to adaptor proteins, such as the tumor necrosis factor receptor-associated factors (TRAFs). Protein complementation is a novel technique to examine protein-protein interaction through the assembly of functional fluorescent proteins or enzymes from inactive fragments. A previous study in our lab demonstrated the use of bimolecular fluorescence complementation (BiFC) to study the assembly of the LMP1 signaling complexes within the plasma membrane of mammalian cells. In the present study, LMP1 was used as bait in a genome-wide BiFC screen with an enhanced retroviral mutagen to identify new LMP1-binding proteins. Our screen identified a novel LMP1-binding protein, transmembrane protein 134 (Tmem134). Tmem134 is a candidate oncogene that is amplified in breast cancer cell lines. Binding, colocalization, and cofractionation between LMP1 and Tmem134 were confirmed. Finally, Tmem134 affected LMP1-induced NF-κB induction. Together, these data suggest that BiFC is a unique and novel platform to identify proteins recruited to the LMP1-signaling complex. PMID:22855487

  14. Live cell imaging of interactions between replicase and capsid protein of Brome mosaic virus using Bimolecular Fluorescence Complementation: Implications for replication and genome packaging

    International Nuclear Information System (INIS)

    In Brome mosaic virus, it was hypothesized that a physical interaction between viral replicase and capsid protein (CP) is obligatory to confer genome packaging specificity. Here we tested this hypothesis by employing Bimolecular Fluorescent Complementation (BiFC) as a tool for evaluating protein–protein interactions in living cells. The efficacy of BiFC was validated by a known interaction between replicase protein 1a (p1a) and protein 2a (p2a) at the endoplasmic reticulum (ER) site of viral replication. Additionally, co-expression in planta of a bona fide pair of interacting protein partners of p1a and p2a had resulted in the assembly of a functional replicase. Subsequent BiFC assays in conjunction with mCherry labeled ER as a fluorescent cellular marker revealed that CP physically interacts with p2a, but not p1a, and this CP:p2a interaction occurs at the cytoplasmic phase of the ER. The significance of the CP:p2a interaction in BMV replication and genome packaging is discussed. - Highlights: • YFP fusion proteins of BMV p1a and p2a are biologically active. • Self-interaction was observed for p1a, p2a and CP. • CP interacts with p2a but not p1a. • Majority of reconstituted YFP resulting from bona fide fusion protein partners localized on ER

  15. Live cell imaging of interactions between replicase and capsid protein of Brome mosaic virus using Bimolecular Fluorescence Complementation: Implications for replication and genome packaging

    Energy Technology Data Exchange (ETDEWEB)

    Chaturvedi, Sonali; Rao, A.L.N., E-mail: arao@ucr.edu

    2014-09-15

    In Brome mosaic virus, it was hypothesized that a physical interaction between viral replicase and capsid protein (CP) is obligatory to confer genome packaging specificity. Here we tested this hypothesis by employing Bimolecular Fluorescent Complementation (BiFC) as a tool for evaluating protein–protein interactions in living cells. The efficacy of BiFC was validated by a known interaction between replicase protein 1a (p1a) and protein 2a (p2a) at the endoplasmic reticulum (ER) site of viral replication. Additionally, co-expression in planta of a bona fide pair of interacting protein partners of p1a and p2a had resulted in the assembly of a functional replicase. Subsequent BiFC assays in conjunction with mCherry labeled ER as a fluorescent cellular marker revealed that CP physically interacts with p2a, but not p1a, and this CP:p2a interaction occurs at the cytoplasmic phase of the ER. The significance of the CP:p2a interaction in BMV replication and genome packaging is discussed. - Highlights: • YFP fusion proteins of BMV p1a and p2a are biologically active. • Self-interaction was observed for p1a, p2a and CP. • CP interacts with p2a but not p1a. • Majority of reconstituted YFP resulting from bona fide fusion protein partners localized on ER.

  16. In planta Protein Interactions of Three Alphacryptoviruses and Three Betacryptoviruses from White Clover, Red Clover and Dill by Bimolecular Fluorescence Complementation Analysis

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    Till Lesker

    2013-10-01

    Full Text Available Plant-infecting viruses of the genera Alpha- and Betacryptovirus within the family Partitiviridae cause no visible effects on their hosts and are only transmitted by cell division and through gametes. The bipartite dsRNA genome is encoding a RNA-dependent RNA polymerase (RdRp and a coat protein (CP. Aside from sequence and structural analysis, the investigation of protein interactions is another step towards virus characterization. Therefore, ORFs of two type members White Clover Cryptic Virus 1 and 2 (WCCV-1 and WCCV-2, as well as the related viruses from Red Clover and Dill were introduced into a bimolecular fluorescence complementation assay. We showed CP-CP dimerization for all tested viruses with localization for alphacryptoviruses at the nuclear membrane and for betacryptoviruses close to cell walls within the cytoplasm. For CPs of WCCV-1 and WCCV-2, deletion mutants were created to determine internal interaction sites. Moreover, RdRp self-interaction was found for all viruses, whereas CP-RdRp interactions were only detectable for the alphacryptoviruses. An intra-genus test of CPs was successful in various virus combinations, whereas an inter-genus interaction of WCCV-1CP and WCCV-2CP was absent. This is the first report of in vivo protein interactions of members in the family Partitiviridae, indicating distinct features of the alpha- and betacryptoviruses.

  17. Identification of Transmembrane Protein 134 as a Novel LMP1-Binding Protein by Using Bimolecular Fluorescence Complementation and an Enhanced Retroviral Mutagen

    OpenAIRE

    Talaty, Pooja; Emery, Amanda; Holthusen, Kirsten; Everly, David N.

    2012-01-01

    Latent membrane protein 1 (LMP1) of Epstein-Barr virus induces constitutive signaling in infected cells. LMP1 signaling requires oligomerization of LMP1 via its transmembrane domain, localization to lipid rafts in the membrane, and association of the LMP1 cytoplasmic domain to adaptor proteins, such as the tumor necrosis factor receptor-associated factors (TRAFs). Protein complementation is a novel technique to examine protein-protein interaction through the assembly of functional fluorescent...

  18. Bimolecular fluorescence complementation analysis of eukaryotic fusion products

    OpenAIRE

    Lin, Ho-Pi; Vincenz, Claudius; Eliceiri, Kevin W.; Kerppola, Tom K.; Ogle, Brenda M.

    2010-01-01

    Background information. Cell fusion is known to underlie key developmental processes in humans and is postulated to contribute to tissue maintenance and even carcinogenesis. The mechanistic details of cell fusion, especially between different cell types, have been difficult to characterize because of the dynamic nature of the process and inadequate means to track fusion products over time. Here we introduce an inducible system for detecting and tracking live cell fusion products in vitro and ...

  19. Bimolecular Complementation to Visualize Filovirus VP40-Host Complexes in Live Mammalian Cells: Toward the Identification of Budding Inhibitors

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    Yuliang Liu

    2011-01-01

    Full Text Available Virus-host interactions play key roles in promoting efficient egress of many RNA viruses, including Ebola virus (EBOV or “e” and Marburg virus (MARV or “m”. Late- (L- domains conserved in viral matrix proteins recruit specific host proteins, such as Tsg101 and Nedd4, to facilitate the budding process. These interactions serve as attractive targets for the development of broad-spectrum budding inhibitors. A major gap still exists in our understanding of the mechanism of filovirus budding due to the difficulty in detecting virus-host complexes and mapping their trafficking patterns in the natural environment of the cell. To address this gap, we used a bimolecular complementation (BiMC approach to detect, localize, and follow the trafficking patterns of eVP40-Tsg101 complexes in live mammalian cells. In addition, we used the BiMC approach along with a VLP budding assay to test small molecule inhibitors identified by in silico screening for their ability to block eVP40 PTAP-mediated interactions with Tsg101 and subsequent budding of eVP40 VLPs. We demonstrated the potential broad spectrum activity of a lead candidate inhibitor by demonstrating its ability to block PTAP-dependent binding of HIV-1 Gag to Tsg101 and subsequent egress of HIV-1 Gag VLPs.

  20. Complement

    Science.gov (United States)

    ... may have lower-than-normal levels of the complement proteins C3 and C4 . Complement activity varies throughout the body. ... Elsevier Saunders; 2013:chap 8. Read More Cirrhosis Complement component 3 (C3) Complement component 4 Glomerulonephritis Hepatitis Hereditary angioedema Kidney ...

  1. Detection of specific DNA sequences by fluorescence amplification: a color complementation assay.

    OpenAIRE

    Chehab, F. F.; Kan, Y W

    1989-01-01

    We have developed a color complementation assay that allows rapid screening of specific genomic DNA sequences. It is based on the simultaneous amplification of two or more DNA segments with fluorescent oligonucleotide primers such that the generation of a color, or combination of colors, can be visualized and used for diagnosis. Color complementation assay obviates the need for gel electrophoresis and has been applied to the detection of a large and small gene deletion, a chromosomal transloc...

  2. Image reconstruction of fluorescent molecular tomography based on the tree structured Schur complement decomposition

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    Wang Jiajun

    2010-05-01

    Full Text Available Abstract Background The inverse problem of fluorescent molecular tomography (FMT often involves complex large-scale matrix operations, which may lead to unacceptable computational errors and complexity. In this research, a tree structured Schur complement decomposition strategy is proposed to accelerate the reconstruction process and reduce the computational complexity. Additionally, an adaptive regularization scheme is developed to improve the ill-posedness of the inverse problem. Methods The global system is decomposed level by level with the Schur complement system along two paths in the tree structure. The resultant subsystems are solved in combination with the biconjugate gradient method. The mesh for the inverse problem is generated incorporating the prior information. During the reconstruction, the regularization parameters are adaptive not only to the spatial variations but also to the variations of the objective function to tackle the ill-posed nature of the inverse problem. Results Simulation results demonstrate that the strategy of the tree structured Schur complement decomposition obviously outperforms the previous methods, such as the conventional Conjugate-Gradient (CG and the Schur CG methods, in both reconstruction accuracy and speed. As compared with the Tikhonov regularization method, the adaptive regularization scheme can significantly improve ill-posedness of the inverse problem. Conclusions The methods proposed in this paper can significantly improve the reconstructed image quality of FMT and accelerate the reconstruction process.

  3. Development of Bimolecular Fluorescence Complementation reagents for the detection of Arabidopsis thaliana KAT1 protein-protein interactions using the Golden Braid cloning system

    OpenAIRE

    MOSSI ALBIACH, ALEJANDRO

    2016-01-01

    [EN] KAT1 is an Arabidopsis thaliana potassium voltage-gated channel of the Shaker family. This ion channel is fundamental for the control of membrane conductance in guard cells, leading to stomatal opening or closing in response to environmental changes. The stomatal movement controls the gas exchange, as well as the amount of water lost due to transpiration. Therefore, the underlying mechanisms of these stomatal movements will likely be influenced by proteins that regulate KAT1 ...

  4. Activation energies of photoinduced unimolecular, bimolecular and termolecular processes on silica gel surfaces.

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    Williams, Siân L; Worrall, David R; Kirkpatrick, Iain; Vancea, Anisoara; Pan, Jiawei

    2011-01-01

    Activation energies for energy and electron transfer have been measured in various systems on silica gel. In the case of ion-electron recombination, a facile technique involving fluorescence recovery is described which complements diffuse reflectance spectroscopy in the study of these systems. In bimolecular anthracene/azulene systems, activation energies have been shown to be independent of pre-treatment temperature in the range 25-210 °C, demonstrating that physisorbed water plays little role in determining diffusion rates on silica gel. In a ternary anthracene/azulene/perylene system, we have for the first time presented comparative activation energies for the diffusion of azulene and its radical cation, and have shown a greater activation energy for diffusion of the latter species. PMID:20978659

  5. Luminescence Spectroscopy and Bimolecular Quenching

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    Demas, J. N.

    1975-01-01

    Describes an undergraduate physical chemistry experiment in which a low cost spectrofluorimeter is used to carry out elementary emission measurements on a transition metal complex. The students measure uncorrected emission and excitation spectra, and determine the rate constant for an exceedingly fast bimolecular reaction, the deactivation of an…

  6. Engineering a ribozyme cleavage-induced split fluorescent aptamer complementation assay

    OpenAIRE

    Ausländer, Simon; Fuchs, David; Hürlemann, Samuel; Ausländer, David; Fussenegger, Martin

    2016-01-01

    Hammerhead ribozymes are self-cleaving RNA molecules capable of regulating gene expression in living cells. Their cleavage performance is strongly influenced by intra-molecular loop–loop interactions, a feature not readily accessible through modern prediction algorithms. Ribozyme engineering and efficient implementation of ribozyme-based genetic switches requires detailed knowledge of individual self-cleavage performances. By rational design, we devised fluorescent aptamer-ribozyme RNA archit...

  7. TRANSGENIC STRATEGY FOR IDENTIFYING SYNAPTIC CONNECTIONS IN MICE BY FLUORESCENCE COMPLEMENTATION (GRASP

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    Masahito eYamagata

    2012-02-01

    Full Text Available In the "GFP reconstitution across synaptic partners" (GRASP method, non-fluorescent fragments of GFP are expressed in two different neurons; the fragments self-assemble at synapses between the two to form a fluorophore. GRASP has proven useful for light microscopic identification of synapses in two invertebrate species, Caenorhabditis elegans and Drosophila melanogaster, but has not yet been applied to vertebrates. Here, we describe GRASP constructs that function in mammalian cells and implement a transgenic strategy in which a Cre-dependent gene switch leads to expression of the two fragments in mutually exclusive neuronal subsets in mice. Using a transgenic line that expresses Cre selectively in rod photoreceptors, we demonstrate labeling of synapses in the outer plexiform layer of the retina. Labeling is specific, in that synapses made by rods remain labeled for at least 6 months whereas nearby synapses made by intercalated cone photoreceptors on many of the same interneurons remain unlabeled. We also generated antisera that label reconstituted GFP but neither fragment in order to amplify the GRASP signal and thereby increase the sensitivity of the method.

  8. Generation of radicals by bimolecular reactions

    Energy Technology Data Exchange (ETDEWEB)

    Denisov, Evgenii T; Denisova, Taisa G [Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Moscow Region (Russian Federation)

    2002-05-31

    The published data on bimolecular processes of radical generation in chain degradation, polymerisation, oxidation and halogenation reactions of organic compounds are systematised and analysed within the framework of the parabolic model of homolytic bimolecular reactions. The specific features of these highly endothermic reactions are discussed with a special emphasis on their striking similarity to radical abstraction processes with identical reaction centres in the transition state. The feasibility of theoretical evaluation of the activation energies and the rate constants of bimolecular reactions in radical generation is demonstrated. The bibliography includes 86 references.

  9. Imaging of mRNA-protein interactions in live cells using novel mCherry trimolecular fluorescence complementation systems.

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    Juan Yin

    Full Text Available Live cell imaging of mRNA-protein interactions makes it possible to study posttranscriptional processes of cellular and viral gene expression under physiological conditions. In this study, red color mCherry-based trimolecular fluorescence complementation (TriFC systems were constructed as new tools for visualizing mRNA-protein interaction in living cells using split mCherry fragments and HIV REV-RRE and TAT-TAR peptide-RNA interaction pairs. The new mCherry TriFC systems were successfully used to image RNA-protein interactions such as that between influenza viral protein NS1 and the 5' UTR of influenza viral mRNAs NS, M, and NP. Upon combination of an mCherry TriFC system with a Venus TriFC system, multiple mRNA-protein interactions could be detected simultaneously in the same cells. Then, the new mCherry TriFC system was used for imaging of interactions between influenza A virus mRNAs and some of adapter proteins in cellular TAP nuclear export pathway in live cells. Adapter proteins Aly and UAP56 were found to associate with three kinds of viral mRNAs. Another adapter protein, splicing factor 9G8, only interacted with intron-containing spliced M2 mRNA. Co-immunoprecipitation assays with influenza A virus-infected cells confirmed these interactions. This study provides long-wavelength-spectrum TriFC systems as new tools for visualizing RNA-protein interactions in live cells and help to understand the nuclear export mechanism of influenza A viral mRNAs.

  10. Complement Test

    Science.gov (United States)

    ... activity) of complement proteins in the blood. Complement components may be measured individually or together to determine whether the system is functioning normally. C3 and C4 are the most frequently measured complement ...

  11. Comparison of fluorescence polarization assay with Rose Bengal (RB test and complement fixation tests for the diagnosis of buffalo (Bubalus bubalis brucellosis in a high-prevalence area

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    G. Iovane

    2010-02-01

    Full Text Available The fluorescence polarisation assay (FPA was evaluated for the serological diagnosis of bovine brucellosis in buffalo (Bubalus Bubalis in southern Italy. This assay uses O-polysaccharide prepared from Brucella Abortus lipopolysaccharide conjugated with fluorescein isothiocyanate as a tracer. It has many methodological advantages over older, more established tests and can be performed in short time. To measure the fluorescence polarization, a Tecan GENios Pro (Prionics fluorescence-polarization analyzer was used with the procedure described by Nielsen et al. 1996. A cut-off value of 117 millipolarization (mP units was used for testing 912 buffalo sera from Campania Region (526 positive sera and 386 negative sera according to the complement fixation test; CFT. All samples were tested with the Rose Bengal plate (RB. Sensitivity and specificity (Sn for RB were 84.0% and 87.8% and for FPA were 92.6% and 88.9 percent. The FPA gave a kappa coefficient of agreement with respect to CFT of 0.755, while RB (relative to the CFT gave coefficients of 0,715. Finally, ROC analysis suggested a cut-off value which did not agree with the one recommended in the test procedure for cow.

  12. Combination of Complement-Dependent Cytotoxicity and Relative Fluorescent Quantification of HLA Length Polymorphisms Facilitates the Detection of a Loss of Heterozygosity

    Directory of Open Access Journals (Sweden)

    Klaus Witter

    2014-01-01

    Full Text Available Loss of heterozygosity (LOH is a common event in malignant cells. In this work we introduce a new approach to identify patients with loss of heterozygosity in the HLA region either at first diagnosis or after HLA mismatched allogeneic HSCT. Diagnosis of LOH requires a high purity of recipient target cells. FACS is time consuming and also frequently prevented by rather nonspecific or unknown immune phenotype. The approach for recipient cell enrichment is based on HLA targeted complement-dependent cytotoxicity (CDC. Relative fluorescent quantification (RFQ analysis of HLA intron length polymorphisms then allows analysis of HLA heterozygosity. The approach is exemplified in recent clinical cases illustrating the detection of an acquired allele loss. As illustrated in one case with DPB1, distinct HLA loci in donor and patient were sufficient for both proof of donor cell removal and evaluation of allele loss in the patient's leukemic cells. Results were confirmed using HLA-B RFQ analysis and leukemia-associated aberrant immunophenotype (LAIP based cell sort. Both results confirmed suspected loss of HLA heterozygosity. Our approach complements or substitutes for FACS-based cell enrichment; hence it may be further developed as novel routine diagnostic tool. This allows rapid recipient cell purification and testing for loss of HLA heterozygosity before and after allogeneic HSCT in easily accessible peripheral blood samples.

  13. RPMDrate: Bimolecular chemical reaction rates from ring polymer molecular dynamics

    OpenAIRE

    Allen, Joshua W.; Green, William H; Suleimanov, Yu. V.

    2013-01-01

    We present RPMDrate, a computer program for the calculation of gas phase bimolecular reaction rate coefficients using the ring polymer molecular dynamics (RPMD) method. The RPMD rate coefficient is calculated using the Bennett–Chandler method as a product of a static (centroid density quantum transition state theory (QTST) rate) and a dynamic (ring polymer transmission coefficient) factor. The computational procedure is general and can be used to treat bimolecular polyatomic reactions of any ...

  14. Analysis of Brownian Dynamics Simulations of Reversible Bimolecular Reactions

    KAUST Repository

    Lipková, Jana

    2011-01-01

    A class of Brownian dynamics algorithms for stochastic reaction-diffusion models which include reversible bimolecular reactions is presented and analyzed. The method is a generalization of the λ-bcȳ model for irreversible bimolecular reactions which was introduced in [R. Erban and S. J. Chapman, Phys. Biol., 6(2009), 046001]. The formulae relating the experimentally measurable quantities (reaction rate constants and diffusion constants) with the algorithm parameters are derived. The probability of geminate recombination is also investigated. © 2011 Society for Industrial and Applied Mathematics.

  15. Recent Advances in Quantum Dynamics of Bimolecular Reactions.

    Science.gov (United States)

    Zhang, Dong H; Guo, Hua

    2016-05-27

    In this review, we survey the latest advances in theoretical understanding of bimolecular reaction dynamics in the past decade. The remarkable recent progress in this field has been driven by more accurate and efficient ab initio electronic structure theory, effective potential-energy surface fitting techniques, and novel quantum scattering algorithms. Quantum mechanical characterization of bimolecular reactions continues to uncover interesting dynamical phenomena in atom-diatom reactions and beyond, reaching an unprecedented level of sophistication. In tandem with experimental explorations, these theoretical developments have greatly advanced our understanding of key issues in reaction dynamics, such as microscopic reaction mechanisms, mode specificity, product energy disposal, influence of reactive resonances, and nonadiabatic effects. PMID:26980305

  16. RPMDrate: Bimolecular chemical reaction rates from ring polymer molecular dynamics

    KAUST Repository

    Suleimanov, Yu.V.

    2013-03-01

    We present RPMDrate, a computer program for the calculation of gas phase bimolecular reaction rate coefficients using the ring polymer molecular dynamics (RPMD) method. The RPMD rate coefficient is calculated using the Bennett-Chandler method as a product of a static (centroid density quantum transition state theory (QTST) rate) and a dynamic (ring polymer transmission coefficient) factor. The computational procedure is general and can be used to treat bimolecular polyatomic reactions of any complexity in their full dimensionality. The program has been tested for the H+H2, H+CH 4, OH+CH4 and H+C2H6 reactions. © 2012 Elsevier B.V. All rights reserved.

  17. Resonance Reaction in Diffusion-Influenced Bimolecular Reactions

    OpenAIRE

    Kolb, Jakob J.; Angioletti-Uberti, Stefano; Dzubiella, Joachim

    2016-01-01

    We investigate the influence of a stochastically fluctuating step-barrier potential on bimolecular reaction rates by exact analytical theory and stochastic simulations. We demonstrate that the system exhibits a new resonant reaction behavior with rate enhancement if an appropriately defined fluctuation decay length is of the order of the system size. Importantly, we find that in the proximity of resonance the standard reciprocal additivity law for diffusion and surface reaction rates is viola...

  18. Bimolecular recombination reactions: K-adiabatic and K-active forms of the bimolecular master equations and analytic solutions

    Science.gov (United States)

    Ghaderi, Nima

    2016-03-01

    Expressions for a K-adiabatic master equation for a bimolecular recombination rate constant krec are derived for a bimolecular reaction forming a complex with a single well or complexes with multiple well, where K is the component of the total angular momentum along the axis of least moment of inertia of the recombination product. The K-active master equation is also considered. The exact analytic solutions, i.e., the K-adiabatic and K-active steady-state population distribution function of reactive complexes, g(EJK) and g(EJ), respectively, are derived for the K-adiabatic and K-active master equation cases using properties of inhomogeneous integral equations (Fredholm type). The solutions accommodate arbitrary intermolecular energy transfer models, e.g., the single exponential, double exponential, Gaussian, step-ladder, and near-singularity models. At the high pressure limit, the krec for both the K-adiabatic and K-active master equations reduce, respectively, to the K-adiabatic and K-active bimolecular Rice-Ramsperger-Kassel-Marcus theory (high pressure limit expressions). Ozone and its formation from O + O2 are known to exhibit an adiabatic K. The ratio of the K-adiabatic to the K-active recombination rate constants for ozone formation at the high pressure limit is calculated to be ˜0.9 at 300 K. Results on the temperature and pressure dependence of the recombination rate constants and populations of O3 will be presented elsewhere.

  19. Kinetics and mechanism of bimolecular electron transfer reaction in quinone-amine systems in micellar solution

    International Nuclear Information System (INIS)

    Photoinduced electron transfer (ET) reactions between anthraquinone derivatives and aromatic amines have been investigated in sodium dodecyl sulphate (SDS) micellar solutions. Significant static quenching of the quinone fluorescence due to high amine concentration in the micellar phase has been observed in steady-state measurements. The bimolecular rate constants for the dynamic quenching in the present systems kqTR, as estimated from the time-resolved measurements, have been correlated with the free energy changes ΔG0 for the ET reactions. Interestingly it is seen that the kqTR vs ΔG0 plot displays an inversion behavior with maximum kqTR at around 0.7 eV, a trend similar to that predicted in Marcus ET theory. Like the present results, Marcus inversion in the kqTR values was also observed earlier in coumarin-amine systems in SDS and TX-100 micellar solutions, with maximum kqTR at around the same exergonicity. These results thus suggest that Marcus inversion in bimolecular ET reaction is a general phenomenon in micellar media. Present observations have been rationalized on the basis of the two-dimensional ET (2DET) theory, which seems to be more suitable for micellar ET reactions than the conventional ET theory. For the quinone-amine systems, it is interestingly seen that kqTR vs ΔG0 plot is somewhat wider in comparison to that of the coumarin-amine systems, even though the maxima in the kqTR vs ΔG0 plots appear at almost similar exergonicity for both the acceptor-donor systems. These observations have been rationalized on the basis of the differences in the reaction windows along the solvation axis, as envisaged within the framework of the 2DET theory, and arise due to the differences in the locations of the quinones and coumarin dyes in the micellar phase

  20. Theory of Crowding Effects on Bimolecular Reaction Rates.

    Science.gov (United States)

    Berezhkovskii, Alexander M; Szabo, Attila

    2016-07-01

    An analytical expression for the rate constant of a diffusion-influenced bimolecular reaction in a crowded environment is derived in the framework of a microscopic model that accounts for: (1) the slowdown of diffusion due to crowding and the dependence of the diffusivity on the distance between the reactants, (2) a crowding-induced attractive short-range potential of mean force, and (3) nonspecific reversible binding to the crowders. This expression spans the range from reaction to diffusion control. Crowding can increase the reaction-controlled rate by inducing an effective attraction between reactants but decrease the diffusion-controlled rate by reducing their relative diffusivity. PMID:27096470

  1. Resonance Reaction in Diffusion-Influenced Bimolecular Reactions

    CERN Document Server

    Kolb, Jakob J; Dzubiella, Joachim

    2016-01-01

    We investigate the influence of a stochastically fluctuating step-barrier potential on bimolecular reaction rates by exact analytical theory and stochastic simulations. We demonstrate that the system exhibits a new resonant reaction behavior with rate enhancement if an appropriately defined fluctuation decay length is of the order of the system size. Importantly, we find that in the proximity of resonance the standard reciprocal additivity law for diffusion and surface reaction rates is violated due to the dynamical coupling of multiple kinetic processes. Together, these findings may have important repercussions on the correct interpretation of various kinetic reaction problems in complex systems, as, e.g., in biomolecular association or catalysis.

  2. Bimolecular reaction dynamics from photoelectron spectroscopy of negative ions

    Energy Technology Data Exchange (ETDEWEB)

    Bradforth, S.E.

    1992-11-01

    The transition state region of a neutral bimolecular reaction may be experimentally investigated by photoelectron spectroscopy of an appropriate negative ion. The photoelectron spectrum provides information on the spectroscopy and dynamics of the short lived transition state and may be used to develop model potential energy surfaces that are semi-quantitative in this important region. The principles of bound [yields] bound negative ion photoelectron spectroscopy are illustrated by way of an example: a full analysis of the photoelectron bands of CN[sup [minus

  3. Communication: Resonance reaction in diffusion-influenced bimolecular reactions

    Science.gov (United States)

    Kolb, Jakob J.; Angioletti-Uberti, Stefano; Dzubiella, Joachim

    2016-02-01

    We investigate the influence of a stochastically fluctuating step-barrier potential on bimolecular reaction rates by exact analytical theory and stochastic simulations. We demonstrate that the system exhibits a new "resonant reaction" behavior with rate enhancement if an appropriately defined fluctuation decay length is of the order of the system size. Importantly, we find that in the proximity of resonance, the standard reciprocal additivity law for diffusion and surface reaction rates is violated due to the dynamical coupling of multiple kinetic processes. Together, these findings may have important repercussions on the correct interpretation of various kinetic reaction problems in complex systems, as, e.g., in biomolecular association or catalysis.

  4. Morse bifurcations of transition states in bimolecular reactions

    Science.gov (United States)

    MacKay, R. S.; Strub, D. C.

    2015-12-01

    The transition states and dividing surfaces used to find rate constants for bimolecular reactions are shown to undergo Morse bifurcations, in which they change diffeomorphism class, and to exist for a large range of energies, not just immediately above the critical energy for first connection between reactants and products. Specifically, we consider capture between two molecules and the associated transition states for the case of non-zero angular momentum and general attitudes. The capture between an atom and a diatom, and then a general molecule are presented, providing concrete examples of Morse bifurcations of transition states and dividing surfaces.

  5. Application of split-green fluorescent protein for topology mapping membrane proteins in Escherichia coli

    DEFF Research Database (Denmark)

    Toddo, Stephen; Soderstrom, Bill; Palombo, Isolde;

    2012-01-01

    /periplasmic location of the N-terminus of a protein. Here, we show that the bimolecular split-green fluorescent protein complementation system can overcome this limitation and can be used to determine the location of both the N- and C-termini of inner membrane proteins in Escherichia coli.......A topology map of a membrane protein defines the location of transmembrane helices and the orientation of soluble domains relative to the membrane. In the absence of a high-resolution structure, a topology map is an essential guide for studying structurefunction relationships. Although these maps...... can be predicted directly from amino acid sequence, the predictions are more accurate if combined with experimental data, which are usually obtained by fusing a reporter protein to the C-terminus of the protein. However, as reporter proteins are large, they cannot be used to report on the cytoplasmic...

  6. Complement component 4

    Science.gov (United States)

    ... may have lower-than-normal levels of the complement proteins C3 and C4 . Complement activity varies throughout the body. ... Saunders; 2013:chap 6. Read More Cirrhosis Complement Complement component 3 (C3) Glomerulonephritis Hepatitis Hereditary angioedema Kidney transplant Lupus nephritis ...

  7. Morse bifurcations of transition states in bimolecular reactions

    CERN Document Server

    MacKay, Robert S

    2015-01-01

    The transition states and dividing surfaces used to find rate constants for bimolecular reactions are shown to undergo qualitative changes, known as Morse bifurcations, and to exist for a large range of energies, not just immediately above the critical energy for first connection between reactants and products. Specifically, we consider capture between two molecules and the associated transition states for the case of non-zero angular momentum and general attitudes. The capture between an atom and a diatom, and then a general molecule are presented, providing concrete examples of Morse bifurcations of transition states and dividing surfaces. The reduction of the $n$-body systems representing the reactions is discussed and reviewed with comments on the difficulties associated with choosing appropriate charts and the global geometry of the reduced spaces.

  8. Bimolecular recombination and complete photocurrent decay in metallophthalocyanine thin films

    Science.gov (United States)

    Noah, Ramsey S.

    Metallophthalocyanines (MPc) are a class of planar small molecule semiconductors that are of great interest due to their applications in organic solar cells. However, a thorough understanding of many of their charge transport properties, especially those related to trap states, is lacking. In previous works the increase of grain size in MPc thin films with higher substrate temperature during the thermal evaporation process was quantified. Here, we investigate the charge transport properties of phthalocyanine with varying grain sizes in five ways: 1) intensity-varied photocurrent measurements are used to study the order of recombination in zinc phthalocyanine (ZnPc) thin films; 2) the conduction dependence on oxygen doping in copper phthalocyanine (CuPc) and ZnPc is investigated through oxygen deprivation in a closed-cycle refrigerator; 3) the complete photocurrent decay in CuPc and ZnPc is explored; 4) the bandgap of CuPc and ZnPc is derived from wide temperature range (˜ 80K - 351K) resistance measurements; 5) thermally stimulated currents (TSC) in CuPc and ZnPc are induced using a modified Reber methodology. An explanation for oxygen doping in these type of thin films is presented and in addition to bimolecular recombination a second model is also applied to measurements of intensity-varied photocurrent. Our data suggest several interesting aspects of the charge transport properties in these organic semiconductors. Recombination may not be dominated by monomolecular processes but instead bimolecular. More amorphous (low deposition temperature) samples show a greater change in conductivity due to oxygen doping. The photocurrent of more crystalline samples decays more rapidly compared to amorphous samples, suggesting that deeper trap states are present in lower deposition temperature samples. The bandgap derived from temperature-varied resistance measurements is systematically low due to slow detrapping. Unlike TSC measurements in micrometer-thick organic films

  9. Complement driven by conformational

    NARCIS (Netherlands)

    Gros, P.; Milder, F.J.; Janssen, B.J.C.

    2008-01-01

    Complement in mammalian plasma recognizes pathogenic, immunogenic and apoptotic cell surfaces, promotes inflammatory responses and marks particles for cell lysis, phagocytosis and B‑cell stimulation. At the heart of the complement system are two large proteins, complement component C3 and protease f

  10. Bimolecular reaction dynamics from photoelectron spectroscopy of negative ions

    Energy Technology Data Exchange (ETDEWEB)

    Bradforth, S.E.

    1992-11-01

    The transition state region of a neutral bimolecular reaction may be experimentally investigated by photoelectron spectroscopy of an appropriate negative ion. The photoelectron spectrum provides information on the spectroscopy and dynamics of the short lived transition state and may be used to develop model potential energy surfaces that are semi-quantitative in this important region. The principles of bound {yields} bound negative ion photoelectron spectroscopy are illustrated by way of an example: a full analysis of the photoelectron bands of CN{sup {minus}}, NCO{sup {minus}} and NCS{sup {minus}}. Transition state photoelectron spectra are presented for the following systems Br + HI, Cl + HI, F + HI, F + CH{sub 3}0H,F + C{sub 2}H{sub 5}OH,F + OH and F + H{sub 2}. A time dependent framework for the simulation and interpretation of the bound {yields} free transition state photoelectron spectra is subsequently developed and applied to the hydrogen transfer reactions Br + HI, F + OH {yields} O({sup 3}P, {sup 1}D) + HF and F + H{sub 2}. The theoretical approach for the simulations is a fully quantum-mechanical wave packet propagation on a collinear model reaction potential surface. The connection between the wavepacket time evolution and the photoelectron spectrum is given by the time autocorrelation function. For the benchmark F + H{sub 2} system, comparisons with three-dimensional quantum calculations are made.

  11. Bimolecular reaction dynamics from photoelectron spectroscopy of negative ions

    International Nuclear Information System (INIS)

    The transition state region of a neutral bimolecular reaction may be experimentally investigated by photoelectron spectroscopy of an appropriate negative ion. The photoelectron spectrum provides information on the spectroscopy and dynamics of the short lived transition state and may be used to develop model potential energy surfaces that are semi-quantitative in this important region. The principles of bound → bound negative ion photoelectron spectroscopy are illustrated by way of an example: a full analysis of the photoelectron bands of CN-, NCO- and NCS-. Transition state photoelectron spectra are presented for the following systems Br + HI, Cl + HI, F + HI, F + CH30H,F + C2H5OH,F + OH and F + H2. A time dependent framework for the simulation and interpretation of the bound → free transition state photoelectron spectra is subsequently developed and applied to the hydrogen transfer reactions Br + HI, F + OH → O(3P, 1D) + HF and F + H2. The theoretical approach for the simulations is a fully quantum-mechanical wave packet propagation on a collinear model reaction potential surface. The connection between the wavepacket time evolution and the photoelectron spectrum is given by the time autocorrelation function. For the benchmark F + H2 system, comparisons with three-dimensional quantum calculations are made

  12. Complement C3

    OpenAIRE

    Dinasarapu, Ashok Reddy; Chandrasekhar, Anjana; Sahu, Arvind; Subramaniam, Shankar

    2012-01-01

    Complement C3 is the central component of the human complement system. It is ~186 kDa in size, consisting of an α-chain (~110 kDa) and a β-chain (~75 kDa) that are connected by cysteine bridges. C3 in its native form is inactive. Cleavage of C3 into C3b (~177 kDa) and C3a (~9 kDa) is a crucial step in the complement activation cascade, which can be initiated by one or more of the three distinct pathways, called alternative, classical and lectin complement pathways. In the alternative pathway,...

  13. Transient expression in Nicotiana benthamiana fluorescent marker lines provides enhanced definition of protein localization, movement and interactions in planta.

    Science.gov (United States)

    Martin, Kathleen; Kopperud, Kristin; Chakrabarty, Romit; Banerjee, Rituparna; Brooks, Robert; Goodin, Michael M

    2009-07-01

    Here, we report on the construction of a novel series of Gateway-compatible plant transformation vectors containing genes encoding autofluorescent proteins, including Cerulean, Dendra2, DRONPA, TagRFP and Venus, for the expression of protein fusions in plant cells. To assist users in the selection of vectors, we have determined the relative in planta photostability and brightness of nine autofluorescent proteins (AFPs), and have compared the use of DRONPA and Dendra2 in photoactivation and photoconversion experiments. Additionally, we have generated transgenic Nicotiana benthamiana lines that express fluorescent protein markers targeted to nuclei, endoplasmic reticulum or actin filaments. We show that conducting bimolecular fluorescence complementation assays in plants that constitutively express cyan fluorescent protein fused to histone 2B provides enhanced data quality and content over assays conducted without the benefit of a subcellular marker. In addition to testing protein interactions, we demonstrate that our transgenic lines that express red fluorescent protein markers offer exceptional support in experiments aimed at defining nuclear or endomembrane localization. Taken together, the new combination of pSITE-BiFC and pSITEII vectors for studying intracellular protein interaction, localization and movement, in conjunction with our transgenic marker lines, constitute powerful tools for the plant biology community. PMID:19309457

  14. Uncertainty for calculating transport on Titan: a probabilistic description of bimolecular diffusion parameters

    CERN Document Server

    Plessis, Sylvain; Mandt, Kathy; Greathouse, Thomas; Luspay-Kuti, Adrienn

    2015-01-01

    Bimolecular diffusion coefficients are important parameters used by atmospheric models to calculate altitude profiles of minor constituents in an atmosphere. Unfortunately, laboratory measurements of these coefficients were never conducted at temperature conditions relevant to the atmosphere of Titan. Here we conduct a detailed uncertainty analysis of the bimolecular diffusion coefficient parameters as applied to Titan's upper atmosphere to provide a better understanding of the impact of uncertainty for this parameter on models. Because temperature and pressure conditions are much lower than the laboratory conditions in which bimolecular diffusion parameters were measured, we apply a Bayesian framework, a problem-agnostic framework, to determine parameter estimates and associated uncertainties. We solve the Bayesian calibration problem using the open-source QUESO library which also performs a propagation of uncertainties in the calibrated parameters to temperature and pressure conditions observed in Titan's u...

  15. Efficient Bimolecular Mechanism of Photochemical Hydrogen Production Using Halogenated Boron-Dipyrromethene (Bodipy) Dyes and a Bis(dimethylglyoxime) Cobalt(III) Complex.

    Science.gov (United States)

    Sabatini, Randy P; Lindley, Brian; McCormick, Theresa M; Lazarides, Theodore; Brennessel, William W; McCamant, David W; Eisenberg, Richard

    2016-01-28

    A series of Boron-dipyrromethene (Bodipy) dyes were used as photosensitizers for photochemical hydrogen production in conjunction with [Co(III)(dmgH)2pyCl] (where dmgH = dimethylglyoximate, py = pyridine) as the catalyst and triethanolamine (TEOA) as the sacrificial electron donor. The Bodipy dyes are fully characterized by electrochemistry, X-ray crystallography, quantum chemistry calculations, femtosecond transient absorption, and time-resolved fluorescence, as well as in long-term hydrogen production assays. Consistent with other recent reports, only systems containing halogenated chromophores were active for hydrogen production, as the long-lived triplet state is necessary for efficient bimolecular electron transfer. Here, it is shown that the photostability of the system improves with Bodipy dyes containing a mesityl group versus a phenyl group, which is attributed to increased electron donating character of the mesityl substituent. Unlike previous reports, the optimal ratio of chromophore to catalyst is established and shown to be 20:1, at which point this bimolecular dye/catalyst system performs 3-4 times better than similar chemically linked systems. We also show that the hydrogen production drops dramatically with excess catalyst concentration. The maximum turnover number of ∼ 700 (with respect to chromophore) is obtained under the following conditions: 1.0 × 10(-4) M [Co(dmgH)2pyCl], 5.0 × 10(-6) M Bodipy dye with iodine and mesityl substituents, 1:1 v:v (10% aqueous TEOA):MeCN (adjusted to pH 7), and irradiation by light with λ > 410 nm for 30 h. This system, containing discrete chromophore and catalyst, is more active than similar linked Bodipy-Co(dmg)2 dyads recently published, which, in conjunction with our other measurements, suggests that the nominal dyads actually function bimolecularly. PMID:26730460

  16. Principles of fluorescence techniques

    CERN Document Server

    2016-01-01

    Fluorescence techniques are being used and applied increasingly in academics and industry. The Principles of Fluorescence Techniques course will outline the basic concepts of fluorescence techniques and the successful utilization of the currently available commercial instrumentation. The course is designed for students who utilize fluorescence techniques and instrumentation and for researchers and industrial scientists who wish to deepen their knowledge of fluorescence applications. Key scientists in the field will deliver theoretical lectures. The lectures will be complemented by the direct utilization of steady-state and lifetime fluorescence instrumentation and confocal microscopy for FLIM and FRET applications provided by leading companies.

  17. Finite Complements in English

    Institute of Scientific and Technical Information of China (English)

    Ronald W. Langacker

    2008-01-01

    This paper explores the conceptual basis of finite complimentation in English.It first considem the distinguishing property of a finite clause,namely grounding,effeeted by tense and the modals.Notions crucial for clausal grounding--including a reality conception and the striving for control at the effective and epistemic levelsalso figure in the semantic import of eomplementation.An essential feature of complement constructions is the involvement of multiple conceptualizers,each with their own conception of reality.The different types of complement and their grammatical markings can be characterized on this basis.Finite complements differ from other types by virtue of expressing an autonomous proposition capable of being apprehended by multiple conceptualizers,each from their own vantage point.Acognitive model representing phases in the striving for epistemic control provides a partial basis for the semantic description of predicates taking finite complements.The same model supports the description of both personal and impersonal complement constructions.

  18. Anthracene Fluorescence Quenching by a Tetrakis (Ketocarboxamide Cavitand

    Directory of Open Access Journals (Sweden)

    Tibor Zoltan Janosi

    2014-01-01

    Full Text Available Quenching of both fluorescence lifetime and fluorescence intensity of anthracene was investigated in the presence of a newly derived tetrakis (ketocarboxamide cavitand at various concentrations. Time-correlated single photon counting method was applied for the lifetime measurements. A clear correlation between the fluorescence lifetime of anthracene as a function of cavitand concentration in dimethylformamide solution was observed. The bimolecular collisional quenching constant was derived from the decrease of lifetime. Fluorescence intensity was measured in the emission wavelength region around 400 nm as a result of excitation at 280 nm. Effective quenching was observed in the presence of the cavitand. The obtained Stern-Volmer plot displayed upward curvature. The results did not follow even extended Stern-Volmer behavior, often used to describe deviations from static bimolecular quenching. To explain our results we adopted the Smoluchowski model and obtained a reasonable estimate for the molecular radius of the cavitand in solution.

  19. The Expression Profile of Complement Components in Podocytes.

    Science.gov (United States)

    Li, Xuejuan; Ding, Fangrui; Zhang, Xiaoyan; Li, Baihong; Ding, Jie

    2016-01-01

    Podocytes are critical for maintaining the glomerular filtration barrier and are injured in many renal diseases, especially proteinuric kidney diseases. Recently, reports suggested that podocytes are among the renal cells that synthesize complement components that mediate glomerular diseases. Nevertheless, the profile and extent of complement component expression in podocytes remain unclear. This study examined the expression profile of complement in podocytes under physiological conditions and in abnormal podocytes induced by multiple stimuli. In total, 23/32 complement component components were detected in podocyte by conventional RT-PCR. Both primary cultured podocytes and immortalized podocytes expressed the complement factors C1q, C1r, C2, C3, C7, MASP, CFI, DAF, CD59, C4bp, CD46, Protein S, CR2, C1qR, C3aR, C5aR, and Crry (17/32), whereas C4, CFB, CFD, C5, C6, C8, C9, MBL1, and MBL2 (9/32) complement factors were not expressed. C3, Crry, and C1q-binding protein were detected by tandem mass spectrometry. Podocyte complement gene expression was affected by several factors (puromycin aminonucleoside (PAN), angiotensin II (Ang II), interleukin-6 (IL-6), and transforming growth factor-β (TGF-β)). Representative complement components were detected using fluorescence confocal microscopy. In conclusion, primary podocytes express various complement components at the mRNA and protein levels. The complement gene expressions were affected by several podocyte injury factors. PMID:27043537

  20. The Expression Profile of Complement Components in Podocytes

    Directory of Open Access Journals (Sweden)

    Xuejuan Li

    2016-03-01

    Full Text Available Podocytes are critical for maintaining the glomerular filtration barrier and are injured in many renal diseases, especially proteinuric kidney diseases. Recently, reports suggested that podocytes are among the renal cells that synthesize complement components that mediate glomerular diseases. Nevertheless, the profile and extent of complement component expression in podocytes remain unclear. This study examined the expression profile of complement in podocytes under physiological conditions and in abnormal podocytes induced by multiple stimuli. In total, 23/32 complement component components were detected in podocyte by conventional RT-PCR. Both primary cultured podocytes and immortalized podocytes expressed the complement factors C1q, C1r, C2, C3, C7, MASP, CFI, DAF, CD59, C4bp, CD46, Protein S, CR2, C1qR, C3aR, C5aR, and Crry (17/32, whereas C4, CFB, CFD, C5, C6, C8, C9, MBL1, and MBL2 (9/32 complement factors were not expressed. C3, Crry, and C1q-binding protein were detected by tandem mass spectrometry. Podocyte complement gene expression was affected by several factors (puromycin aminonucleoside (PAN, angiotensin II (Ang II, interleukin-6 (IL-6, and transforming growth factor-β (TGF-β. Representative complement components were detected using fluorescence confocal microscopy. In conclusion, primary podocytes express various complement components at the mRNA and protein levels. The complement gene expressions were affected by several podocyte injury factors.

  1. The power-law reaction rate coefficient for an elementary bimolecular reaction

    OpenAIRE

    Yin, Cangtao; Du, Jiulin

    2013-01-01

    The power-law TST reaction rate coefficient for an elementary bimolecular reaction is studied when the reaction takes place in a nonequilibrium system with power-law distributions. We derive a generalized TST rate coefficient, which not only depends on a power-law parameter but also on the reaction coordinate frequency of transition state. The numerical analyses show a very strong dependence of TST rate coefficient on the power-law parameter, and clearly indicate that a tiny deviation from un...

  2. Uncertainty for calculating transport on Titan: A probabilistic description of bimolecular diffusion parameters

    Science.gov (United States)

    Plessis, S.; McDougall, D.; Mandt, K.; Greathouse, T.; Luspay-Kuti, A.

    2015-11-01

    Bimolecular diffusion coefficients are important parameters used by atmospheric models to calculate altitude profiles of minor constituents in an atmosphere. Unfortunately, laboratory measurements of these coefficients were never conducted at temperature conditions relevant to the atmosphere of Titan. Here we conduct a detailed uncertainty analysis of the bimolecular diffusion coefficient parameters as applied to Titan's upper atmosphere to provide a better understanding of the impact of uncertainty for this parameter on models. Because temperature and pressure conditions are much lower than the laboratory conditions in which bimolecular diffusion parameters were measured, we apply a Bayesian framework, a problem-agnostic framework, to determine parameter estimates and associated uncertainties. We solve the Bayesian calibration problem using the open-source QUESO library which also performs a propagation of uncertainties in the calibrated parameters to temperature and pressure conditions observed in Titan's upper atmosphere. Our results show that, after propagating uncertainty through the Massman model, the uncertainty in molecular diffusion is highly correlated to temperature and we observe no noticeable correlation with pressure. We propagate the calibrated molecular diffusion estimate and associated uncertainty to obtain an estimate with uncertainty due to bimolecular diffusion for the methane molar fraction as a function of altitude. Results show that the uncertainty in methane abundance due to molecular diffusion is in general small compared to eddy diffusion and the chemical kinetics description. However, methane abundance is most sensitive to uncertainty in molecular diffusion above 1200 km where the errors are nontrivial and could have important implications for scientific research based on diffusion models in this altitude range.

  3. Detonation wave solutions and linear stability in a four component gas with bimolecular chemical reaction

    OpenAIRE

    Carvalho, Filipe; De Silva, A.W.; Soares, A. J.

    2015-01-01

    We consider a four component gas undergoing a bimolecular chemical reaction of type A1 + A2 = A3 + A4, described by the Boltzmann equation (BE) for chemically reactive mixtures. We adopt hard-spheres elastic cross sections and modified line-of-centers reactive cross sections depending on both the activation energy and geometry of the reactive collisions. Then we consider the hydrodynamic limit specified by the reactive Euler equations, in an earlier stage of the chemical reaction, when the ga...

  4. Differences in the Abilities to Mechanically Eliminate Activation Energies for Unimolecular and Bimolecular Reactions

    Science.gov (United States)

    Kochhar, Gurpaul S.; Mosey, Nicholas J.

    2016-03-01

    Mechanochemistry, i.e. the application of forces, F, at the molecular level, has attracted significant interest as a means of controlling chemical reactions. The present study uses quantum chemical calculations to explore the abilities to mechanically eliminate activation energies, ΔE‡, for unimolecular and bimolecular reactions. The results demonstrate that ΔE‡ can be eliminated for unimolecular reactions by applying sufficiently large F along directions that move the reactant and/or transition state (TS) structures parallel to the zero-F reaction coordinate, S0. In contrast, eliminating ΔE‡ for bimolecular reactions requires the reactant to undergo a force-induced shift parallel to S0 irrespective of changes in the TS. Meeting this requirement depends upon the coupling between F and S0 in the reactant. The insights regarding the differences in eliminating ΔE‡ for unimolecular and bimolecular reactions, and the requirements for eliminating ΔE‡, may be useful in practical efforts to control reactions mechanochemically.

  5. Clinical significance of complement deficiencies.

    Science.gov (United States)

    Pettigrew, H David; Teuber, Suzanne S; Gershwin, M Eric

    2009-09-01

    The complement system is composed of more than 30 serum and membrane-bound proteins, all of which are needed for normal function of complement in innate and adaptive immunity. Historically, deficiencies within the complement system have been suspected when young children have had recurrent and difficult-to-control infections. As our understanding of the complement system has increased, many other diseases have been attributed to deficiencies within the complement system. Generally, complement deficiencies within the classical pathway lead to increased susceptibility to encapsulated bacterial infections as well as a syndrome resembling systemic lupus erythematosus. Complement deficiencies within the mannose-binding lectin pathway generally lead to increased bacterial infections, and deficiencies within the alternative pathway usually lead to an increased frequency of Neisseria infections. However, factor H deficiency can lead to membranoproliferative glomerulonephritis and hemolytic uremic syndrome. Finally, deficiencies within the terminal complement pathway lead to an increased incidence of Neisseria infections. Two other notable complement-associated deficiencies are complement receptor 3 and 4 deficiency, which result from a deficiency of CD18, a disease known as leukocyte adhesion deficiency type 1, and CD59 deficiency, which causes paroxysmal nocturnal hemoglobinuria. Most inherited deficiencies of the complement system are autosomal recessive, but properidin deficiency is X-linked recessive, deficiency of C1 inhibitor is autosomal dominant, and mannose-binding lectin and factor I deficiencies are autosomal co-dominant. The diversity of clinical manifestations of complement deficiencies reflects the complexity of the complement system. PMID:19758139

  6. A ubiquitin-10 promoter-based vector set for fluorescent protein tagging facilitates temporal stability and native protein distribution in transient and stable expression studies.

    Science.gov (United States)

    Grefen, Christopher; Donald, Naomi; Hashimoto, Kenji; Kudla, Jörg; Schumacher, Karin; Blatt, Michael R

    2010-10-01

    Fluorescent tagging of proteins and confocal imaging techniques have become methods of choice in analysing the distributions and dynamic characteristics of proteins at the subcellular level. In common use are a number of strategies for transient expression that greatly reduce the preparation time in advance of imaging, but their applications are limited in success outside a few tractable species and tissues. We previously developed a simple method to transiently express fluorescently-tagged proteins in Arabidopsis root epidermis and root hairs. We describe here a set of Gateway-compatable vectors with fluorescent tags incorporating the ubiqutin-10 gene promoter (P(UBQ10) ) of Arabidopsis that gives prolonged expression of the fluorescently-tagged proteins, both in tobacco and Arabidopsis tissues, after transient transformation, and is equally useful in generating stably transformed lines. As a proof of principle, we carried out transformations with fluorescent markers for the integral plasma membrane protein SYP121, a member of the SNARE family of vesicle-trafficking proteins, and for DHAR1, a cytosolic protein that facilitates the scavenging of reactive oxygen species. We also carried out transformations with SYP121 and its interacting partner, the KC1 K(+) channel, to demonstrate the utility of the methods in bimolecular fluorescence complementation (BiFC). Transient transformations of Arabidopsis using Agrobacterium co-cultivation methods yielded expression in all epidermal cells, including root hairs and guard cells. Comparative studies showed that the P(UBQ10) promoter gives similar levels of expression to that driven by the native SYP121 promoter, faithfully reproducing the characteristics of protein distributions at the subcellular level. Unlike the 35S-driven construct, expression under the P(UBQ10) promoter remained elevated for periods in excess of 2 weeks after transient transformation. This toolbox of vectors and fluorescent tags promises significant

  7. Material properties in complement activation

    DEFF Research Database (Denmark)

    Moghimi, S. Moein; Andersen, Alina Joukainen; Ahmadvand, Davoud;

    2011-01-01

    activation differently and through different sensing molecules and initiation pathways. The importance of material properties in triggering complement is considered and mechanistic aspects discussed. Mechanistic understanding of complement events could provide rational approaches for improved material design...

  8. Complement component 3 (C3)

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/003539.htm Complement component 3 (C3) To use the sharing features on this page, ... be some throbbing. Why the Test is Performed C3 and C4 are the most commonly measured complement components. A complement test may be used to monitor ...

  9. Laboratory tests for disorders of complement and complement regulatory proteins.

    Science.gov (United States)

    Shih, Angela R; Murali, Mandakolathur R

    2015-12-01

    The complement pathway is a cascade of proteases that is involved in immune surveillance and innate immunity, as well as adaptive immunity. Dysfunction of the complement cascade may be mediated by aberrations in the pathways of activation, complement regulatory proteins, or complement deficiencies, and has been linked to a number of hematologic disorders, including paroxysmal noctural hemoglobinuria (PNH), hereditary angioedema (HAE), and atypical hemolytic-uremic syndrome (aHUS). Here, current laboratory tests for disorders of the complement pathway are reviewed, and their utility and limitations in hematologic disorders and systemic diseases are discussed. Current therapeutic advances targeting the complement pathway in treatment of complement-mediated hematologic disorders are also reviewed. PMID:26437749

  10. Ancient origins: complement in invertebrates

    Directory of Open Access Journals (Sweden)

    SV Nair

    2005-08-01

    Full Text Available Proteins with obvious similarities to mammalian complement are widely distributed in the animal kingdom.In the vertebrate lineage, deuterostomes like sea urchins and tunicates express proteins that arehomologues of C3, the central component of the vertebrate complement cascade. Their genomes alsoencode molecules resembling factor B from the “alternative” complement activation pathway; andtunicates have collagenous lectins of the type that can activate complement in the absence of antibodies.This suggests that the core components of the complement system evolved before antibodies, which firstappear in jawed fish.

  11. Examining coagulation-complement crosstalk: complement activation and thrombosis.

    Science.gov (United States)

    Foley, Jonathan H

    2016-05-01

    The coagulation and complement systems are ancestrally related enzymatic cascades of the blood. Although their primary purposes have diverged over the past few hundred million years, they remain inextricably connected. Both complement and coagulation systems limit infection by pathogens through innate immune mechanisms. Recently, it has been shown that hyperactive complement (in particular, elevated C5a/C5b-9) is involved in the pathogenesis (including thrombosis) of diseases such as paroxysmal nocturnal hemoglobinuria, atypical haemolytic uremic syndrome, antiphospholipid syndrome and bacteremia. Although these diseases together account for many thrombosis cases, there are many more where complement activation is not considered a causative factor leading to thrombosis. To better understand what role complement may play in the pathogenesis of thrombosis a better understanding of the mechanisms that cause over-active complement in thrombotic disease is required. PMID:27207425

  12. Complement's participation in acquired immunity

    DEFF Research Database (Denmark)

    Nielsen, Claus Henrik; Leslie, Robert Graham Quinton

    2002-01-01

    B cell receptor for antigen (BCR), a complex composed of the iC3b/C3d fragment-binding complement type 2 receptor (CR2, CD21) and its signaling element CD19 and the IgG-binding receptor FcgammaRIIb (CD32). The positive or negative outcome of signaling through this triad is determined by the context...... in which antigen is seen, be it alone or in association with natural or induced antibodies and/or C3-complement fragments. The aim of this review is to describe the present status of our understanding of complement's participation in acquired immunity and the regulation of autoimmune responses.......The preliminary evidence for the involvement of complement in promoting primary humoral responses dates back over a quarter of a century. However, it is only in the course of the past decade or so that the detailed mechanisms underlying complement's influence have been characterized in depth. It is...

  13. Pathology development stage and its influence on the delayed fluorescence kinetics of molecular probes

    International Nuclear Information System (INIS)

    This paper describes regularity of the delayed fluorescence kinetics changes of xanthene dyes in the cancer cells received from tumors of different diameter. It shows that the rate constant of bimolecular reactions (singlet–triplet T−1Δg(O2) and triplet–triplet annihilations) as well as thermoactive fluorescence decrease with increasing pathological process development stage. It could be a result of both more expressed cancer cell hypoxia and a change in cytoplasm viscosity. (paper)

  14. Data preprocessing for parameter estimation. An application to a reactive bimolecular transport model

    CERN Document Server

    Cuch, Daniel A; Hasi, Claudio D El

    2015-01-01

    In this work we are concerned with the inverse problem of the estimation of modeling parameters for a reactive bimolecular transport based on experimental data that is non-uniformly distributed along the interval where the process takes place. We proposed a methodology that can help to determine the intervals where most of the data should be taken in order to obtain a good estimation of the parameters. For the purpose of reducing the cost of laboratory experiments, we propose to simulate data where is needed and it is not available, a PreProcesing Data Fitting (PPDF).We applied this strategy on the estimation of parameters for an advection-diffusion-reaction problem in a porous media. Each step is explained in detail and simulation results are shown and compared with previous ones.

  15. Sequence and solvent effects on telomeric DNA bimolecular G-quadruplex folding kinetics.

    Science.gov (United States)

    Marchand, Adrien; Ferreira, Rubén; Tateishi-Karimata, Hisae; Miyoshi, Daisuke; Sugimoto, Naoki; Gabelica, Valérie

    2013-10-17

    Telomeric DNA sequences are particularly polymorphic: the adopted structure is exquisitely sensitive to the sequence and to the chemical environment, for example, solvation. Dehydrating conditions are known to stabilize G-quadruplex structures, but information on how solvation influences the individual rates of folding and unfolding of G-quadruplexes remains scarce. Here, we used electrospray mass spectrometry for the first time to monitor bimolecular G-quadruplex formation from 12-mer telomeric strands, in the presence of common organic cosolvents (methanol, ethanol, isopropanol, and acetonitrile). Based on the ammonium ion distribution, the total dimer signal was decomposed into contributions from the parallel and antiparallel structures to obtain individual reaction rates, and the antiparallel G-quadruplex structure was found to form faster than the parallel one. A dimeric reaction intermediate, in rapid equilibrium with the single strands, was also identified. Organic cosolvents increase the stability of the final structures mainly by increasing the folding rates. Our quantitative analysis of reaction rate dependence on cosolvent percentage shows that organic cosolvent molecules can be captured or released upon G-quadruplex formation, highlighting that they are not inert with DNA. In contrast to the folding rates, the G-quadruplex unfolding rates are almost insensitive to solvation effects, but are instead governed by the sequence and by the final structure: parallel dimers dissociate slower than antiparallel dimers only when thymine bases are present at the 5'-end. These results contribute unraveling the folding pathways of telomeric G-quadruplexes. The solvent effects revealed here enlighten that G-quadruplex structure in dehydrated, and molecularly crowded environments are modulated by the nature of cosolvent (e.g., methanol favors antiparallel structures) due to direct interactions, and by the time scale of the reaction, with >200-fold acceleration of

  16. Force Dynamics of Verb Complementation

    Directory of Open Access Journals (Sweden)

    Jacek Woźny

    2015-12-01

    Full Text Available Force Dynamics of Verb ComplementationThe concepts of motion and force are both extensively discussed in cognitive linguistics literature. But they are discussed separately. The first usually in the context of ‘motion situations’ (Talmy, Slobin, Zlatev, the other as part of the Force Dynamics framework, which was developed by Talmy. The aim of this paper is twofold: first, to argue that the concepts of force and motion should not be isolated but considered as two inseparable parts of force-motion events. The second goal is to prove that the modified Force Dynamics (force-motion framework can be used for precise characterization of the verb complementation patterns. To this end, a random sample of 50 sentences containing the verb ‘went’ is analyzed, demonstrating the differences between the categories of intensive and intransitive complementation with respect to the linguistically coded parameters of force and motion.

  17. Fluorescence quenching of TMR by guanosine in oligonucleotides

    Institute of Scientific and Technical Information of China (English)

    QU Peng; CHEN XuDong; ZHOU XiaoXue; LI Xun; ZHAO XinSheng

    2009-01-01

    Nucleotide-specific fluorescence quenching in fluorescently labeled DNA has many applications in biotechnology. We have studied the inter- and intra-molecular quenching of tetramethylrhodamine (TMR) by nucleotides to better understand their quenching mechanism and influencing factors. In agreement with previous work, dGMP can effectively quench TMR, while the quenching of TMR by other nucleotides is negligible. The Stern-Volmer plot between TMR and dGMP delivers a bimolecular quenching constant of Ks= 52.3 M~(-1). The fluorescence of TMR in labeled oligonucleotides decreases efficiently through photoinduced electron transfer by guanosine. The quenching rate constant between TMR and guanosine was measured using fluorescence correlation spectroscopy (FCS). In addition, our data show that the steric hindrance by bases around guanosine has significant effect on the G-quenching. The availability of these data should be useful in designing fluorescent oligonucleotides and understanding the G-quenching process.

  18. Fluorescence quenching of TMR by guanosine in oligonucleotides

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Nucleotide-specific fluorescence quenching in fluorescently labeled DNA has many applications in biotechnology. We have studied the inter-and intra-molecular quenching of tetramethylrhodamine (TMR) by nucleotides to better understand their quenching mechanism and influencing factors. In agreement with previous work, dGMP can effectively quench TMR, while the quenching of TMR by other nucleotides is negligible. The Stern-Volmer plot between TMR and dGMP delivers a bimolecular quenching constant of Ks=52.3 M-1. The fluorescence of TMR in labeled oligonucleotides decreases efficiently through photoinduced electron transfer by guanosine. The quenching rate constant between TMR and guanosine was measured using fluorescence correlation spectroscopy (FCS). In addition, our data show that the steric hindrance by bases around guanosine has significant effect on the G-quenching. The availability of these data should be useful in designing fluorescent oligonucleotides and understanding the G-quenching process.

  19. The lectin pathway of complement

    DEFF Research Database (Denmark)

    Ballegaard, Vibe Cecilie Diederich; Haugaard, Anna Karen; Garred, P;

    2014-01-01

    The pattern recognition molecules of the lectin complement pathway are important components of the innate immune system with known functions in host-virus interactions. This paper summarizes current knowledge of how these intriguing molecules, including mannose-binding lectin (MBL), Ficolin-1, -2...

  20. Complement: Alive and Kicking Nanomedicines

    DEFF Research Database (Denmark)

    Andersen, Alina Joukainen; Hashemi, S.H.; Andresen, Thomas Lars;

    2009-01-01

    Administration of liposome- and polymer-based clinical nanomedicines, as well as many other proposed multifunctional nanoparticles, often triggers hypersensitivity reactions without the involvement of IgE. These anaphylactic reactions are believed to be secondary to activation of the complement s...

  1. Complement and Isomorphism on Bipolar Fuzzy Graphs

    Directory of Open Access Journals (Sweden)

    Ali Asghar Talebi

    2014-12-01

    Full Text Available In this paper, we discuss some properties of the self complement and self weak complement bipolar fuzzy graphs, and get a sufficient condition for a bipolar fuzzy graph to be the self weak complement bipolar fuzzy graph. Also we investigate relations between operations union, join, and complement on bipolar fuzzy graphs.

  2. Complement and Isomorphism on Bipolar Fuzzy Graphs

    OpenAIRE

    Ali Asghar Talebi; Hossein Rashmanlou

    2014-01-01

    In this paper, we discuss some properties of the self complement and self weak complement bipolar fuzzy graphs, and get a sufficient condition for a bipolar fuzzy graph to be the self weak complement bipolar fuzzy graph. Also we investigate relations between operations union, join, and complement on bipolar fuzzy graphs.

  3. On the Temperature Dependence of the Rate Constant of the Bimolecular Reaction of two Hydrated Electrons

    Directory of Open Access Journals (Sweden)

    S.L. Butarbutar

    2013-08-01

    Full Text Available It has been a longstanding issue in the radiation chemistry of water that, even though H2 is a molecular product, its “escape” yield g(H2 increases with increasing temperature. A main source of H2 is the bimolecular reaction of two hydrated electrons (eaq. The temperature dependence of the rate constant of this reaction (k1, measured under alkaline conditions, reveals that the rate constant drops abruptly above ~150°C. Recently, it has been suggested that this temperature dependence should be regarded as being independent of pH and used in high-temperature modeling of near-neutral water radiolysis. However, when this drop in the eaq self-reaction rate constant is included in low (isolated spurs and high (cylindrical tracks linear energy transfer (LET modeling calculations, g(H2 shows a marked downward discontinuity at ~150°C which is not observed experimentally. The consequences of the presence of this discontinuity in g(H2 for both low and high LET radiation are briefly discussed in this communication. It is concluded that the applicability of the sudden drop in k1 observed at ~150°C in alkaline water to near-neutral water is questionable and that further measurements of the rate constant in pure water are highly desirable.

  4. Bimolecular Excited-State Electron Transfer with Surprisingly Long-Lived Radical Ions

    KAUST Repository

    Alsam, Amani A.

    2015-09-02

    We explored the excited-state interactions of bimolecular, non-covalent systems consisting of cationic poly[(9,9-di(3,3’-N,N’-trimethyl-ammonium) propyl fluorenyl-2,7-diyl)-alt-co-(9,9-dioctyl-fluorenyl-2,7-diyl)] diiodide salt (PFN) and 1,4-dicyanobenzene (DCB) using steady-state and time-resolved techniques, including femto- and nanosecond transient absorption and femtosecond infrared spectroscopies with broadband capabilities. The experimental results demonstrated that photo-induced electron transfer from PFN to DCB occurs on the picosecond time scale, leading to the formation of PFN+• and DCB-• radical ions. Interestingly, real-time observations of the vibrational marker modes on the acceptor side provided direct evidence and insight into the electron transfer process indirectly inferred from UV-Vis experiments. The band narrowing on the picosecond time scale observed on the antisymmetric C-N stretching vibration of the DCB radical anion provides clear experimental evidence that a substantial part of the excess energy is channeled into vibrational modes of the electron transfer product and that the geminate ion pairs dissociate. More importantly, our nanosecond time-resolved data indicate that the charge-separated state is very long lived ( 30 ns) due to the dissociation of the contact radical ion pair into free ions. Finally, the fast electron transfer and slow charge recombination anticipate the current donor−acceptor system with potential applications in organic solar cells.

  5. A transition in the spatially integrated reaction rate of bimolecular reaction-diffusion systems

    Science.gov (United States)

    Arshadi, Masoud; Rajaram, Harihar

    2015-09-01

    Numerical simulations of diffusion with bimolecular reaction demonstrate a transition in the spatially integrated reaction rate—increasing with time initially, and transitioning to a decrease with time. In previous work, this reaction-diffusion problem has been analyzed as a Stefan problem involving a distinct moving boundary (reaction front), leading to predictions that front motion scales as √t, and correspondingly the spatially integrated reaction rate decreases as the square root of time 1/√t. We present a general nondimensionalization of the problem and a perturbation analysis to show that there is an early time regime where the spatially integrated reaction rate scales as √t rather than 1/√t. The duration of this early time regime (where the spatially integrated reaction rate is kinetically rather than diffusion controlled) is shown to depend on the kinetic rate parameters, diffusion coefficients, and initial concentrations of the two species. Numerical simulation results confirm the theoretical estimates of the transition time. We present illustrative calculations in the context of in situ chemical oxidation for remediation of fractured rock systems where contaminants are largely dissolved in the rock matrix. We consider different contaminants of concern (COCs), including TCE, PCE, MTBE, and RDX. While the early time regime is very short lived for TCE, it can persist over months to years for MTBE and RDX, due to slow oxidation kinetics.

  6. Complement pathways and meningococcal disease : diagnostic aspects

    DEFF Research Database (Denmark)

    Sjöholm, A G; Truedsson, L; Jensenius, Jens Christian

    2001-01-01

    activation on the bacterial surface (6,7). The newly discovered mannan-binding lectin (MBL) pathway of complement activation appears to be protective against many types of infection (8) and adds previously unsuspected aspects of innate immunity to complement-mediated defense. Interestingly, immune responses...... are influenced by complement (9), and it could be that acquisition of protective antibodies is impaired in some types of complement deficiency. A further aspect of interactions between Neisseria and complement is the potential role of membrane-bound complement regulators as cellular receptors for the...

  7. Modeling Bimolecular Reactions and Transport in Porous Media Via Particle Tracking

    Energy Technology Data Exchange (ETDEWEB)

    Dong Ding; David Benson; Amir Paster; Diogo Bolster

    2012-01-01

    We use a particle-tracking method to simulate several one-dimensional bimolecular reactive transport experiments. In this numerical method, the reactants are represented by particles: advection and dispersion dominate the flow, and molecular diffusion dictates, in large part, the reactions. The particle/particle reactions are determined by a combination of two probabilities dictated by the physics of transport and energetics of reaction. The first is that reactant particles occupy the same volume over a short time interval. The second is the conditional probability that two collocated particles favorably transform into a reaction. The first probability is a direct physical representation of the degree of mixing in an advancing displacement front, and as such lacks empirical parameters except for the user-defined number of particles. This number can be determined analytically from concentration autocovariance, if this type of data is available. The simulations compare favorably to two physical experiments. In one, the concentration of product, 1,2-naphthoquinoe-4-aminobenzene (NQAB) from reaction between 1,2-naphthoquinone-4-sulfonic acid (NQS) and aniline (AN), was measured at the outflow of a column filled with glass beads at different times. In the other, the concentration distribution of reactants (CuSO_4 and EDTA^{4-}) and products (CuEDTA^{4-}) were quantified by snapshots of transmitted light through a column packed with cryloite sand. The thermodynamic rate coefficient in the latter experiment was 10^7 times greater than the former experiment, making it essentially instantaneous. When compared to the solution of the advection-dispersion-reaction equation (ADRE) with the well-mixed reaction coefficient, the experiments and the particle-tracking simulations showed on the order of 20% to 40% less overall product, which is attributed to poor mixing. The poor mixing also leads to higher product concentrations on the edges of the mixing zones, which the particle

  8. Complement activation and complement control proteins in acute pancreatitis.

    OpenAIRE

    Whicher, J T; Barnes, M. P.; Brown, A; Cooper, M J; Read, R; Walters, G; Williamson, R C

    1982-01-01

    Serum levels of the complement proteins C3, C4, C1 inhibitor (C1 INH), factor I (C3b inactivator) and factor H (BIH) and plasma levels of cleavage products of C3 (C3c) and factor B were measured in 26 patients with acute pancreatitis. Breakdown of C3 occurred in 19 patients, as shown by a reduction in C3 level and the presence of C3c. C4 levels, however, did not fall and factor B breakdown products were not detected, thus suggesting that enzymatic cleavage of C3 occurred without significant i...

  9. Complement activation in experimental human malaria infection.

    NARCIS (Netherlands)

    Roestenberg, M.; McCall, M.B.B.; Mollnes, T.E.; Deuren, M. van; Sprong, T.; Klasen, I.S.; Hermsen, C.C.; Sauerwein, R.W.; Ven, A.J.A.M. van der

    2007-01-01

    The objective of this study was to investigate complement activation in uncomplicated, early phases of human malaria. Fifteen healthy volunteers were experimentally infected with Plasmodium falciparum malaria. Parasitemia and complement activation products were assessed. During blood stage parasitem

  10. An improved europium release assay for complement-mediated cytolysis.

    Science.gov (United States)

    Cui, J; Bystryn, J C

    1992-02-14

    An improved assay for complement-mediated cytolysis is described. The target cells are labeled with europium complexed to diethylenetriaminopentaacetate (Eu-DTPA). Cytolysis caused by antibody plus complement leads to the release of the Eu-DTPA complex which is then formed into a highly fluorescent chelate by the addition of 2-naphthoyltrifluoroacetone (2-NTA). The amount of europium chelate formed--a measurement of cell death--is then quantified with a time-resolved fluorometer. The results of the assay are reproducible. Complement-mediated cytolysis when measured by europium release was five times more sensitive than when measured by conventional 51Cr release and three times than when measured by trypan blue exclusion. Because europium does not decay, target cells can be labelled in batches and stored frozen until use, which speeds and simplifies the assay. Thus, europium release assay is a simple and quantitative method to measure complement-mediated cytolysis which is sensitive and more rapid than conventional assays. PMID:1541836

  11. Oka properties of some hypersurface complements

    CERN Document Server

    Hanysz, Alexander

    2011-01-01

    Oka manifolds can be viewed as the "opposite" of Kobayashi hyperbolic manifolds. Kobayashi asked whether the complement in projective space of a generic hypersurface of sufficiently high degree is hyperbolic. Therefore it is natural to investigate Oka properties of complements of low degree hypersurfaces. We determine which complements of hyperplane arrangements in projective space are Oka. A related question is which hypersurfaces in affine space have Oka complements. We give some results for graphs of meromorphic functions.

  12. conformational complexity of complement component C3

    NARCIS (Netherlands)

    Janssen, B.J.C.

    2007-01-01

    The complement system is an important part of the immune system and critical for the elimination of pathogens. In mammals the complement system consists of an intricate set of about 35 soluble and cell-surface plasma proteins. Central to complement is component C3, a large protein of 1,641 residues.

  13. Genetics Home Reference: complement factor I deficiency

    Science.gov (United States)

    ... the complement system decreases blood levels of another complement protein called C3, reducing the immune system's ability to fight infections. ... in my area? Other Names for This Condition C3 inactivator deficiency complement component 3 inactivator deficiency Related Information How are ...

  14. Charge carrier concentration dependence of encounter-limited bimolecular recombination in phase-separated organic semiconductor blends

    Science.gov (United States)

    Heiber, Michael C.; Nguyen, Thuc-Quyen; Deibel, Carsten

    2016-05-01

    Understanding how the complex intermolecular configurations and nanostructure present in organic semiconductor donor-acceptor blends impacts charge carrier motion, interactions, and recombination behavior is a critical fundamental issue with a particularly major impact on organic photovoltaic applications. In this study, kinetic Monte Carlo (KMC) simulations are used to numerically quantify the complex bimolecular charge carrier recombination behavior in idealized phase-separated blends. Recent KMC simulations have identified how the encounter-limited bimolecular recombination rate in these blends deviates from the often used Langevin model and have been used to construct the new power mean mobility model. Here, we make a challenging but crucial expansion to this work by determining the charge carrier concentration dependence of the encounter-limited bimolecular recombination coefficient. In doing so, we find that an accurate treatment of the long-range electrostatic interactions between charge carriers is critical, and we further argue that many previous KMC simulation studies have used a Coulomb cutoff radius that is too small, which causes a significant overestimation of the recombination rate. To shed more light on this issue, we determine the minimum cutoff radius required to reach an accuracy of less than ±10 % as a function of the domain size and the charge carrier concentration and then use this knowledge to accurately quantify the charge carrier concentration dependence of the recombination rate. Using these rigorous methods, we finally show that the parameters of the power mean mobility model are determined by a newly identified dimensionless ratio of the domain size to the average charge carrier separation distance.

  15. Irreversible bimolecular reactions with inertia: from the trapping to the target setting at finite densities.

    Science.gov (United States)

    Piazza, Francesco; Foffi, Giuseppe; De Michele, Cristiano

    2013-06-19

    We investigate numerically pseudo-first-order irreversible bimolecular reactions of the type A + B → B between hard spheres undergoing event-driven Brownian dynamics. We study the encounter rate and the survival probability of A particles as functions of the packing fraction ϕ in the trapping (a single particle diffusing among static non-overlapping traps) and target (many traps diffusing in the presence of a single static target particle) settings, as well as in the case of diffusing traps and particles (full mobility). We show that, since inertial effects are accounted for in our simulation protocol, the standard Smoluchowski theory of coagulation of non-interacting colloids is recovered only at times greater than a characteristic time Δt, marking the transition from the under-damped to the over-damped regime. We show that the survival probability S(t) decays exponentially during this first stage, with a rate 1/τ0 is proportional to φ. Furthermore, we work out a simple analytical expression that is able to capture to an excellent extent the numerical results for t < Δt at low and intermediate densities. Moreover, we demonstrate that the time constant of the asymptotic exponential decay of S(t) for diffusing traps and particles is k(S)(-1), where kS = 4π(DA + DB)Rρ is the Smoluchowski rate. Detailed analyses of the effective decay exponent β = d [log(-logS(t))]/d (logt) and of the steady-state encounter rate reveal that the full mobility and trapping problem are characterized by very similar kinetics, rather different from the target problem. Our results do not allow one to ascertain whether the prediction S(t) is proportional to exp(-at(3/2)) (a = const.) as t → ∞ for the trapping problem in 3D is indeed recovered. In fact, at high density, S(t) is dominated by short encounter times, which makes it exceedingly hard to record the events corresponding to the exploration of large, trap-free regions. As a consequence, at high densities the steady

  16. The Complement System in Liver Diseases

    Institute of Scientific and Technical Information of China (English)

    Xuebin Qin; Bin Gao

    2006-01-01

    The complement system plays an important role in mediating both acquired and innate responses to defend against microbial infection, and in disposing immunoglobins and apoptotic cells. The liver (mainly hepatocytes) is responsible for biosynthesis of about 80-90% of plasma complement components and expresses a variety of complement receptors.Recent evidence from several studies suggests that the complement system is also involved in the pathogenesis of a variety of liver disorders including liver injury and repair, fibrosis, viral hepatitis, alcoholic liver disease, and liver ischemia/reperfusion injury. In this review, we will discuss the potential role of the complement system in the pathogenesis of liver diseases.

  17. Infrared laser induced organic reactions. 2. Laser vs. thermal inducment of unimolecular and hydrogen bromide catalyzed bimolecular dehydration of alcohols

    International Nuclear Information System (INIS)

    It has been demonstrated that a mixture of reactant molecules can be induced by pulsed infrared laser radiation to react via a route which is totally different from the pathway resulting from heating the mixture at 3000C. The high-energy unimolecular elimination of H2O from ethanol in the presence of 2-propanol and HBr can be selectively induced with a pulsed CO2 laser in preference to either a lower energy bimolecular HBr-catalyzed dehydration or the more facile dehydration of 2-propanol. Heating the mixture resulted in the almost exclusive reaction of 2-propanol to produce propylene. It was demonstrated that the bimolecular ethanol + HBr reaction cannot be effectively induced by the infrared laser radiation as evidenced by the detrimental effect on the yield of ethylene as the HBr pressure was increased. The selective, nonthermal inducement of H2O elimination from vibrationally excited ethanol in the presence of 2-propanol required relatively low reactant pressures. At higher pressures intermolecular V--V energy transfer allowed the thermally more facile dehydration from 2-propanol to become the predominant reaction channel

  18. The Lectin Pathway of Complement and Biocompatibility

    DEFF Research Database (Denmark)

    Hein, Estrid; Garred, Peter

    2015-01-01

    activation, the coagulation system and the complement system. The complement system is an important part of the initial immune response and consists of fluid phase molecules in the blood stream. Three different activation pathways can initiate the complement system, the lectin, the classical and the...... been broadly documented. However, the specific role of lectin pathway and the pattern recognition molecules initiating the pathway has only been transiently investigated. Here we review the current data on the field....

  19. Role of complement in multiorgan failure

    OpenAIRE

    Rittirsch, Daniel; Redl, Heinz; Huber-Lang, Markus

    2012-01-01

    Multiorgan failure (MOF) represents the leading cause of death in patients with sepsis and systemic inflammatory response syndrome (SIRS) following severe trauma. The underlying immune response is highly complex and involves activation of the complement system as a crucial entity of innate immunity. Uncontrolled activation of the complement system during sepsis and SIRS with in excessive generation of complement activation products contributes to an ensuing dysfunction of various organ system...

  20. Complement and hyper acute rejection

    Directory of Open Access Journals (Sweden)

    Al-Rabia Mohammed

    2009-01-01

    Full Text Available Organ transplantation has been a major development in clinical medicine but its success has been marred by the immune system′s capacity to respond to "non-self" cells and tissues. A full molecular understanding of this mechanism and the myriad triggers for immune rejection is yet to be elucidated. Consequently, immunosuppressive drugs remain the mainstay of post-transplant ma-nagement; however, these interventions have side effects such as increased incidence of cancer, post-transplant lymphoproliferative disorders, susceptibility to infection if not managed appro-priately and the inconvenience to the patient of lifelong treatment. Novel therapeutic approaches based on molecular understanding of immunological processes are thus needed in this field. The notion that factors influencing successful transplants might be of use as therapeutic approaches is both scientifically and medically appealing. Recent developments in the understanding of successful transplants are expected to provide new opportunities for safer transplantation. This article reviews the present understanding of the molecular basis of rejection and the role of complement in this process as well as the possibility of generating "intelligent" therapy that better target crucial components of hyper-acute rejections.

  1. conformational complexity of complement component C3

    OpenAIRE

    Janssen, B.J.C.

    2007-01-01

    The complement system is an important part of the immune system and critical for the elimination of pathogens. In mammals the complement system consists of an intricate set of about 35 soluble and cell-surface plasma proteins. Central to complement is component C3, a large protein of 1,641 residues. Activation of C3 into C3b leads to several molecular and cellular responses, and to stimulation of the adaptive immune system. Chapter 1 gives an overview of the complement system, the central com...

  2. Role of Complement in Multiorgan Failure

    Directory of Open Access Journals (Sweden)

    Daniel Rittirsch

    2012-01-01

    Full Text Available Multiorgan failure (MOF represents the leading cause of death in patients with sepsis and systemic inflammatory response syndrome (SIRS following severe trauma. The underlying immune response is highly complex and involves activation of the complement system as a crucial entity of innate immunity. Uncontrolled activation of the complement system during sepsis and SIRS with in excessive generation of complement activation products contributes to an ensuing dysfunction of various organ systems. In the present review, mechanisms of the inflammatory response in the development of MOF in sepsis and SIRS with particular focus on the complement system are discussed.

  3. Unusual charge transport and reduced bimolecular recombination in PDTSiTzTz:PC71BM bulk heterojunction blend

    International Nuclear Information System (INIS)

    Solar cells with bulk heterojunction active layers containing donor-acceptor copolymer PDTSiTzTz exhibit persistent high fill factors with thicknesses up to 400 nm. Transport and recombination in a blend of PDTSiTzTz and fullerene derivative PC71BM is studied using lateral organic photovoltaic structures. This material system is characterized by carrier-concentration-dependent charge carrier mobilities, a strongly reduced bimolecular recombination factor, and a negative Poole–Frenkel coefficient. The analysis provides an explanation for the relatively thickness-independent fill factor behaviour seen in solar cells using the copolymer PDTSiTzTz. Cumulative insights from this copolymer can be employed for future organic photovoltaic material development, study of existing high performance bulk heterojunciton blends, and improved solar cell design. (paper)

  4. Complement activation by Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Jensen, E T; Kharazmi, A; Garred, P;

    1993-01-01

    In chronic infections, such as the bronchopulmonary Pseudomonas aeruginosa infection in cystic fibrosis (CF) patients, bacteria persist despite an intact host immune defense and frequent antibiotic treatment. An important reason for the persistence of the bacteria is their capacity for the biofilm...... mode of growth. In this study we investigated the role of biofilms in activation of complement, a major contributor to the inflammatory process. Complement activation by P. aeruginosa was examined in a complement consumption assay, production of C3 and factor B conversion products assessed by crossed...... immuno-electrophoresis, C5a generation tested by a PMN chemotactic assay, and terminal complement complex formation measured by ELISA. Two of the four assays showed that P. aeruginosa grown in biofilm activated complement less than planktonic bacteria, and all assays showed that activation by intact...

  5. Complement resistance mechanisms of Klebsiella pneumoniae.

    Science.gov (United States)

    Doorduijn, Dennis J; Rooijakkers, Suzan H M; van Schaik, Willem; Bardoel, Bart W

    2016-10-01

    The current emergence of antibiotic-resistant bacteria causes major problems in hospitals worldwide. To survive within the host, bacterial pathogens exploit several escape mechanisms to prevent detection and killing by the immune system. As a major player in immune defense, the complement system recognizes and destroys bacteria via different effector mechanisms. The complement system can label bacteria for phagocytosis or directly kill Gram-negative bacteria via insertion of a pore-forming complex in the bacterial membrane. The multi-drug resistant pathogen Klebsiella pneumoniae exploits several mechanisms to resist complement. In this review, we present an overview of strategies used by K. pneumoniae to prevent recognition and killing by the complement system. Understanding these complement evasion strategies is crucial for the development of innovative strategies to combat K. pneumoniae. PMID:27364766

  6. Nucleic acid encoding a self-assembling split-fluorescent protein system

    Energy Technology Data Exchange (ETDEWEB)

    Waldo, Geoffrey S; Cabantous, Stephanie

    2014-04-01

    The invention provides a protein labeling and detection system based on self-complementing fragments of fluorescent and chromophoric proteins. The system of the invention is exemplified with various combinations of self-complementing fragments derived from Aequorea victoria Green Fluorescent Protein (GFP), which are used to detect and quantify protein solubility in multiple assay formats, both in vitro and in vivo.

  7. Nucleic acid encoding a self-assembling split-fluorescent protein system

    Energy Technology Data Exchange (ETDEWEB)

    Waldo, Geoffrey S.; Cabantous, Stephanie

    2015-07-14

    The invention provides a protein labeling and detection system based on self-complementing fragments of fluorescent and chromophoric proteins. The system of the invention is exemplified with various combinations of self-complementing fragments derived from Aequorea victoria Green Fluorescent Protein (GFP), which are used to detect and quantify protein solubility in multiple assay formats, both in vitro and in vivo.

  8. Nucleic acid encoding a self-assembling split-fluorescent protein system

    Science.gov (United States)

    Waldo, Geoffrey S.; Cabantous, Stephanie

    2011-06-07

    The invention provides a protein labeling and detection system based on self-complementing fragments of fluorescent and chromophoric proteins. The system of the invention is exemplified with various combinations of self-complementing fragments derived from Aequorea victoria Green Fluorescent Protein (GFP), which are used to detect and quantify protein solubility in multiple assay formats, both in vitro and in vivo.

  9. Viral mimicry of the complement system

    Indian Academy of Sciences (India)

    John Bernet; Jayati Mullick; Akhilesh K Singh; Arvind Sahu

    2003-04-01

    The complement system is a potent innate immune mechanism consisting of cascades of proteins which are designed to fight against and annul intrusion of all the foreign pathogens. Although viruses are smaller in size and have relatively simple structure, they are not immune to complement attack. Thus, activation of the complement system can lead to neutralization of cell-free viruses, phagocytosis of C3b-coated viral particles, lysis of virus-infected cells, and generation of inflammatory and specific immune responses. However, to combat host responses and succeed as pathogens, viruses not only have developed/adopted mechanisms to control complement, but also have turned these interactions to their own advantage. Important examples include poxviruses, herpesviruses, retroviruses, paramyxoviruses and picornaviruses. In this review, we provide information on the various complement evasion strategies that viruses have developed to thwart the complement attack of the host. A special emphasis is given on the interactions between the viral proteins that are involved in molecular mimicry and the complement system.

  10. Sequence Effect on the Topology of 3 + 1 Interlocked Bimolecular DNA G-Quadruplexes.

    Science.gov (United States)

    Gao, Shang; Cao, Yanwei; Yan, Yuting; Guo, Xinhua

    2016-05-17

    Electrospray ionization mass spectrometry (ESI-MS) combined with fluorescence, circular dichroism, UV spectrophotometer, and native polyacrylamide gel electrophoresis techniques are used to study structural features of interlocked dimers formed by DNA sequence 93del (GGGGTGGGAGGAGGGT) and its derivatives. Herein, we demonstrate that the interlocked dimers can be distinguished from stacked dimers formed by sequences T30923 (GGGTGGGTGGGTGGGT) and T30177 (GTGGTGGGTGGGTGGGT). In addition, loop length, the base at 5'-end, and the isolation of T and TT to the first 4G tract do significantly influence the formation and topologies of interlocked dimers. Furthermore, our results suggest that the 4G tract and the 2G tract in various locations in the 93del derivative sequence can form interlocked structure. This work not only provides new insight into the assembly of 3 + 1 interlocked DNA conformations but also demonstrates that ESI-MS combined with other analytical methods is rapid and useful for DNA structural studies. PMID:27027538

  11. Autocrine Effects of Tumor-Derived Complement

    Directory of Open Access Journals (Sweden)

    Min Soon Cho

    2014-03-01

    Full Text Available We describe a role for the complement system in enhancing cancer growth. Cancer cells secrete complement proteins that stimulate tumor growth upon activation. Complement promotes tumor growth via a direct autocrine effect that is partially independent of tumor-infiltrating cytotoxic T cells. Activated C5aR and C3aR signal through the PI3K/AKT pathway in cancer cells, and silencing the PI3K or AKT gene in cancer cells eliminates the progrowth effects of C5aR and C3aR stimulation. In patients with ovarian or lung cancer, higher tumoral C3 or C5aR mRNA levels were associated with decreased overall survival. These data identify a role for tumor-derived complement proteins in promoting tumor growth, and they therefore have substantial clinical and therapeutic implications.

  12. Nomenclature for human complement factor B*

    OpenAIRE

    1992-01-01

    In this note is recommended a unified nomenclature for allotypes and variants of human complement factor B, which was approved by the Nomenclature Committee of the International Union of Immunological Societies (IUIS).

  13. Complement-targeted therapeutics in periodontitis

    OpenAIRE

    Hajishengallis, George; Lambris, John D.

    2013-01-01

    Periodontitis is a prevalent oral chronic inflammatory disease which, in severe forms, may exert a major impact on systemic health. Clinical and histological observations, as well as experimental animal studies, suggest involvement of the complement system in periodontitis. However, the precise roles of the various complement components and pathways in periodontitis have only recently started to be elucidated. In this paper, we review recent progress in the field and discuss the potential of ...

  14. J Fluorescence

    OpenAIRE

    Resch-Genger, U.; Hoffmann, K.; Nietfeld, W; A. Engel; Neukammer, J.; Nitschke, R.; Ebert, P.; Macdonald, R

    2005-01-01

    The scope of this paper is to illustrate the need for an improved quality assurance in fluorometry. For this purpose, instrumental sources of error and their influences on the reliability and comparability of fluorescence data are highlighted for frequently used photoluminescence techniques ranging from conventional macro- and microfluorometry over fluorescence microscopy and flow cytometry to microarray technology as well as in vivo fluorescence imaging. Particularly, the need for and requir...

  15. Surviving mousepox infection requires the complement system.

    Directory of Open Access Journals (Sweden)

    Elizabeth A Moulton

    2008-12-01

    Full Text Available Poxviruses subvert the host immune response by producing immunomodulatory proteins, including a complement regulatory protein. Ectromelia virus provides a mouse model for smallpox where the virus and the host's immune response have co-evolved. Using this model, our study investigated the role of the complement system during a poxvirus infection. By multiple inoculation routes, ectromelia virus caused increased mortality by 7 to 10 days post-infection in C57BL/6 mice that lack C3, the central component of the complement cascade. In C3(-/- mice, ectromelia virus disseminated earlier to target organs and generated higher peak titers compared to the congenic controls. Also, increased hepatic inflammation and necrosis correlated with these higher tissue titers and likely contributed to the morbidity in the C3(-/- mice. In vitro, the complement system in naïve C57BL/6 mouse sera neutralized ectromelia virus, primarily through the recognition of the virion by natural antibody and activation of the classical and alternative pathways. Sera deficient in classical or alternative pathway components or antibody had reduced ability to neutralize viral particles, which likely contributed to increased viral dissemination and disease severity in vivo. The increased mortality of C4(-/- or Factor B(-/- mice also indicates that these two pathways of complement activation are required for survival. In summary, the complement system acts in the first few minutes, hours, and days to control this poxviral infection until the adaptive immune response can react, and loss of this system results in lethal infection.

  16. Complement and fungal pathogens: an update.

    Science.gov (United States)

    Speth, Cornelia; Rambach, Günter; Würzner, Reinhard; Lass-Flörl, Cornelia

    2008-11-01

    Fungal infections are a serious complication in immunocompromised patients such as human immunodeficiency virus-infected individuals, patients with organ transplantations or with haematological neoplasia. The lethality of opportunistic fungal infection is high despite a growing arsenal of antimycotic drugs, implying the urgent need for supportive immunological therapies to strengthen the current inefficient antimicrobial defences of the immunocompromised host. Therefore, increasing effort has been directed to investigating the interplay between fungi and the host immunity and thus to find starting points for additional therapeutic approaches. In this article, we review the actual state of the art concerning the role of complement in the pathogenesis of fungal infections. Important aspects include the activation of the complement system by the fungal pathogen, the efficiency of the complement-associated antimicrobial functions and the arsenal of immune evasion strategies applied by the fungi. The twin functions of complement as an interactive player of the innate immunity and at the same time as a modulator of the adaptive immunity make this defence weapon a particularly interesting therapeutic candidate to mobilise a more effective immune response and to strengthen in one fell swoop a broad spectrum of different immune reactions. However, we also mention the 'Yin-Yang' nature of the complement system in fungal infections, as growing evidence assigns to complement a contributory part in the pathogenesis of fungus-induced allergic manifestations. PMID:18705662

  17. High Fc Density Particles Result in Binary Complement Activation but Tunable Macrophage Phagocytosis

    Science.gov (United States)

    Sulchek, Todd; Pacheco, Patricia; White, David

    2014-03-01

    Macrophage phagocytosis and complement system activation represent two key components of the immune system and both can be activated through the presentation of multiple Fc domains of IgG antibodies. We have created functionalized micro- and nanoparticles with various densities of Fc domains to understand the modulation of the immune system for eventual use as a novel immunomodulation platform. Phagocytosis assays were carried out by adding functionalized particles to macrophage cells and quantitatively determined using fluorescent microscopy and flow cytometry. Complement system activation by the functionalized particles in human serum was quantified with an enzyme immunoassay. Our phagocytosis assay revealed a strong dependence on particle size and Fc density. For small particles, as the Fc density increased, the number of particles phagocytosed also increased. Large particles were phagocytosed at significantly lower levels and showed no dependency on Fc density. Complement was successfully activated at levels comparable to positive controls for small particles at high Fc densities. However at low Fc densities, there is a significant decrease in complement activation. This result suggests a binary response for complement system activation with a threshold density for successful activation. Therefore, varying the Fc density on micro/nanoparticles resulted in a tunable response in macrophage phagocytosis while a more binary response for complement activation.

  18. Complement and Antibody-mediated Enhancement of Red Blood Cell Invasion and Growth of Malaria Parasites.

    Science.gov (United States)

    Biryukov, Sergei; Angov, Evelina; Landmesser, Mary E; Spring, Michele D; Ockenhouse, Christian F; Stoute, José A

    2016-07-01

    Plasmodium falciparum malaria is a deadly pathogen. The invasion of red blood cells (RBCs) by merozoites is a target for vaccine development. Although anti-merozoite antibodies can block invasion in vitro, there is no efficacy in vivo. To explain this discrepancy we hypothesized that complement activation could enhance RBC invasion by binding to the complement receptor 1 (CR1). Here we show that a monoclonal antibody directed against the merozoite and human polyclonal IgG from merozoite vaccine recipients enhanced RBC invasion in a complement-dependent manner and that soluble CR1 inhibited this enhancement. Sialic acid-independent strains, that presumably are able to bind to CR1 via a native ligand, showed less complement-dependent enhancement of RBC invasion than sialic acid-dependent strains that do not utilize native CR1 ligands. Confocal fluorescent microscopy revealed that complement-dependent invasion resulted in aggregation of CR1 at the RBC surface in contact with the merozoite. Finally, total anti-P. berghei IgG enhanced parasite growth and C3 deficiency decreased parasite growth in mice. These results demonstrate, contrary to current views, that complement activation in conjunction with antibodies can paradoxically aid parasites invade RBCs and should be considered in future design and testing of merozoite vaccines. PMID:27333049

  19. Assembly and activation of alternative complement components on endothelial cell-anchored ultra-large von Willebrand factor links complement and hemostasis-thrombosis.

    Directory of Open Access Journals (Sweden)

    Nancy A Turner

    Full Text Available BACKGROUND: Vascular endothelial cells (ECs express and release protein components of the complement pathways, as well as secreting and anchoring ultra-large von Willebrand factor (ULVWF multimers in long string-like structures that initiate platelet adhesion during hemostasis and thrombosis. The alternative complement pathway (AP is an important non-antibody-requiring host defense system. Thrombotic microangiopathies can be associated with defective regulation of the AP (atypical hemolytic-uremic syndrome or with inadequate cleavage by ADAMTS-13 of ULVWF multimeric strings secreted by/anchored to ECs (thrombotic thrombocytopenic purpura. Our goal was to determine if EC-anchored ULVWF strings caused the assembly and activation of AP components, thereby linking two essential defense mechanisms. METHODOLOGY/PRINCIPAL FINDINGS: We quantified gene expression of these complement components in cultured human umbilical vein endothelial cells (HUVECs by real-time PCR: C3 and C5; complement factor (CF B, CFD, CFP, CFH and CFI of the AP; and C4 of the classical and lectin (but not alternative complement pathways. We used fluorescent microscopy, monospecific antibodies against complement components, fluorescent secondary antibodies, and the analysis of >150 images to quantify the attachment of HUVEC-released complement proteins to ULVWF strings secreted by, and anchored to, the HUVECs (under conditions of ADAMTS-13 inhibition. We found that HUVEC-released C4 did not attach to ULVWF strings, ruling out activation of the classical and lectin pathways by the strings. In contrast, C3, FB, FD, FP and C5, FH and FI attached to ULVWF strings in quantitative patterns consistent with assembly of the AP components into active complexes. This was verified when non-functional FB blocked the formation of AP C3 convertase complexes (C3bBb on ULVWF strings. CONCLUSIONS/SIGNIFICANCE: AP components are assembled and activated on EC-secreted/anchored ULVWF multimeric

  20. Simulation study of the losses and influences of geminate and bimolecular recombination on the performances of bulk heterojunction organic solar cells

    Institute of Scientific and Technical Information of China (English)

    朱键卓; 祁令辉; 杜会静; 柴莺春

    2015-01-01

    We use the method of device simulation to study the losses and influences of geminate and bimolecular recombinations on the performances and properties of the bulk heterojunction organic solar cells. We find that a fraction of electrons (holes) in the device are collected by anode (cathode). The direction of the corresponding current is opposite to the direction of photocurrent. And the current density increases with the bias increasing but decreases as bimolecular recombination (BR) or geminate recombination (GR) intensity increases. The maximum power, short circuit current, and fill factor display a stronger dependence on GR than on BR. While the influences of GR and BR on open circuit voltage are about the same. Our studies shed a new light on the loss mechanism and may provide a new way of improving the efficiency of bulk heterojunction organic solar cells.

  1. The Epidermal Growth Factor Receptor Is a Regulator of Epidermal Complement Component Expression and Complement Activation

    DEFF Research Database (Denmark)

    Abu-Humaidan, Anas H A; Ananthoju, Nageshwar; Mohanty, Tirthankar;

    2014-01-01

    The complement system is activated in response to tissue injury. During wound healing, complement activation seems beneficial in acute wounds but may be detrimental in chronic wounds. We found that the epidermal expression of many complement components was only increased to a minor extent in skin...... wounds in vivo and in cultured keratinocytes after exposure to supernatant from stimulated mononuclear cells. In contrast, the epidermal expression of complement components was downregulated in ex vivo injured skin lacking the stimulation from infiltrating inflammatory cells but with intact injury...

  2. Phylogenetic aspects of the complement system.

    Science.gov (United States)

    Zarkadis, I K; Mastellos, D; Lambris, J D

    2001-01-01

    During evolution two general systems of immunity have emerged: innate or, natural immunity and adaptive (acquired), or specific immunity. The innate system is phylogenetically older and is found in some form in all multicellular organisms, whereas the adaptive system appeared about 450 million years ago and is found in all vertebrates except jawless fish. The complement system in higher vertebrates plays an important role as an effector of both the innate and the acquired immune response, and also participates in various immunoregulatory processes. In lower vertebrates complement is activated by the alternative and lectin pathways and is primarily involved in the opsonization of foreign material. The Agnatha (the most primitive vertebrate species) possess the alternative and lectin pathways while cartilaginous fish are the first species in which the classical pathway appears following the emergence of immunoglobulins. The rest of the poikilothermic species, ranging from teleosts to reptilians, appear to contain a well-developed complement system resembling that of the homeothermic vertebrates. It seems that most of the complement components have appeared after the duplication of primordial genes encoding C3/C4/C5, fB/C2, C1s/C1r/MASP-1/MASP-2, and C6/C7/C8/C9 molecules, in a process that led to the formation of distinct activation pathways. However, unlike homeotherms, several species of poikilotherms (e.g. trout) have recently been shown to possess multiple forms of complement components (C3, factor B) that are structurally and functionally more diverse than those of higher vertebrates. We hypothesize that this remarkable diversity has allowed these animals to expand their innate capacity for immune recognition and response. Recent studies have also indicated the possible presence of complement receptors in protochordates and lower vertebrates. In conclusion, there is considerable evidence suggesting that the complement system is present in the entire lineage of

  3. Origin of the high open circuit voltage in planar heterojunction perovskite solar cells: Role of the reduced bimolecular recombination

    Science.gov (United States)

    Yang, Wenchao; Yao, Yao; Wu, Chang-Qin

    2015-03-01

    The high open circuit voltage is an attractive feature for the currently popular organic-inorganic hybrid perovskite solar cells. In this paper, by employing the macroscopic device model simulation, we investigate its origin for the planar heterojunction perovskite solar cells. Based on the calculated current density-voltage characteristics, it is revealed that compared to the excitonic solar cells, the fast thermal-activated exciton dissociation in the bulk due to the small exciton binding energy may improve the short circuit current and the fill factor, but its beneficial role on the open circuit voltage is marginal. The most significant contribution for the open circuit voltage comes from the reduced bimolecular recombination. In the perovskites, with the recombination prefactor many orders of magnitude smaller than that based on the Langevin's theory, the internal charge density level is significantly enhanced and the density gradient is removed, leading to the high quasi-Fermi level splitting and thus the small open circuit voltage loss. For the nonradiative recombination pathway due to the deep trap states, it may induce significant loss of open circuit voltage as the trap density is high, while for the moderately low density its effect on the open circuit voltage is small and negligible.

  4. Molecular beam studies of unimolecular and bimolecular chemical reaction dynamics using VUV synchrotron radiation as a product probe

    Energy Technology Data Exchange (ETDEWEB)

    Blank, D.A.

    1997-08-01

    This dissertation describes the use of a new molecular beam apparatus designed to use tunable VUV synchrotron radiation for photoionization of the products from scattering experiments. The apparatus was built at the recently constructed Advanced Light Source at Lawrence Berkeley National Laboratory, a third generation 1-2 GeV synchrotron radiation source. The new apparatus is applied to investigations of the dynamics of unimolecular reactions, photodissociation experiments, and bimolecular reactions, crossed molecular beam experiments. The first chapter describes the new apparatus and the VUV radiation used for photoionization. This is followed by a number of examples of the many advantages provided by using VUV photoionization in comparison with the traditional technique of electron bombardment ionization. At the end of the chapter there is a discussion of the data analysis employed in these scattering experiments. The remaining four chapters are complete investigations of the dynamics of four chemical systems using the new apparatus and provide numerous additional examples of the advantages provided by VUV photoionizaiton of the products. Chapters 2-4 are photofragment translational spectroscopy studies of the photodissociation dynamics of dimethyl sulfoxide, acrylonitrile, and vinyl chloride following absorption at 193 mn. All of these systems have multiple dissociation channels and provide good examples of the ability of the new apparatus to unravel the complex UV photodissociation dynamics that can arise in small polyatomic molecules.

  5. The influence of the “cage effect” on the mechanism of reversible bimolecular multistage chemical reactions in solutions

    International Nuclear Information System (INIS)

    Manifestations of the “cage effect” at the encounters of reactants are theoretically treated by the example of multistage reactions in liquid solutions including bimolecular exchange reactions as elementary stages. It is shown that consistent consideration of quasi-stationary kinetics of multistage reactions (possible only in the framework of the encounter theory) for reactions proceeding near reactants contact can be made on the basis of the concepts of a “cage complex.” Though mathematically such a consideration is more complicated, it is more clear from the standpoint of chemical notions. It is established that the presence of the “cage effect” leads to some important effects not inherent in reactions in gases or those in solutions proceeding in the kinetic regime, such as the appearance of new transition channels of reactant transformation that cannot be caused by elementary event of chemical conversion for the given mechanism of reaction. This results in that, for example, rate constant values of multistage reaction defined by standard kinetic equations of formal chemical kinetics from experimentally measured kinetics can differ essentially from real values of these constants

  6. Effect of micellar environment on Marcus correlation curves for photoinduced bimolecular electron transfer reactions

    International Nuclear Information System (INIS)

    Photoinduced electron transfer (ET) between coumarin dyes and aromatic amine has been investigated in two cationic micelles, namely, cetyltrimethyl ammonium bromide (CTAB) and dodecyltrimethyl ammonium bromide (DTAB), and the results have been compared with those observed earlier in sodium dodecyl sulphate (SDS) and triton-X-100 (TX-100) micelles for similar donor-acceptor pairs. Due to a reasonably high effective concentration of the amines in the micellar Stern layer, the steady-state fluorescence results show significant static quenching. In the time-resolved (TR) measurements with subnanosecond time resolution, contribution from static quenching is avoided. Correlations of the dynamic quenching constants (kqTR), as estimated from the TR measurements, show the typical bell-shaped curves with the free-energy changes (ΔG0) of the ET reactions, as predicted by the Marcus outersphere ET theory. Comparing present results with those obtained earlier for similar coumarin-amine systems in SDS and TX-100 micelles, it is seen that the inversion in the present micelles occurs at an exergonicity (-ΔG0>∼1.2-1.3 eV) much higher than that observed in SDS and TX-100 micelles (-ΔG0>∼0.7 eV), which has been rationalized based on the relative propensities of the ET and solvation rates in different micelles. In CTAB and DTAB micelles, the kqTR values are lower than the solvation rates, which result in the full contribution of the solvent reorganization energy (λs) towards the activation barrier for the ET reaction. Contrary to this, in SDS and TX-100 micelles, kqTR values are either higher or comparable with the solvation rates, causing only a partial contribution of λs in these cases. Thus, Marcus inversion in present cationic micelles is inferred to be the true inversion, whereas that in the anionic SDS and neutral TX-100 micelles are understood to be the apparent inversion, as envisaged from two-dimensional ET theory

  7. Applying complement therapeutics to rare diseases.

    Science.gov (United States)

    Reis, Edimara S; Mastellos, Dimitrios C; Yancopoulou, Despina; Risitano, Antonio M; Ricklin, Daniel; Lambris, John D

    2015-12-01

    Around 350 million people worldwide suffer from rare diseases. These may have a genetic, infectious, or autoimmune basis, and several include an inflammatory component. Launching of effective treatments can be very challenging when there is a low disease prevalence and limited scientific insights into the disease mechanisms. As a key trigger of inflammatory processes, complement has been associated with a variety of diseases and has become an attractive therapeutic target for conditions involving inflammation. In view of the clinical experience acquired with drugs licensed for the treatment of rare diseases such as hereditary angioedema and paroxysmal nocturnal hemoglobinuria, growing evidence supports the safety and efficacy of complement therapeutics in restoring immune balance and preventing aggravation of clinical outcomes. This review provides an overview of the candidates currently in the pharmaceutical pipeline with potential to treat orphan diseases and discusses the molecular mechanisms triggered by complement involved with the disease pathogenesis. PMID:26341313

  8. Goat serums for fluorescent antibody conjugates to chlamydial antigens.

    OpenAIRE

    Tessler, J.

    1984-01-01

    Serums from goats hyperimmunized with Chlamydia psittaci consistently produce antichlamydial fluorescent antibody conjugate of high titer. The titer of the fluorescent antibody conjugate prepared from a given serum correlated well with the titer obtained by agar gel precipitin, but not with the complement fixation. The agar gel precipitin test can be used to predict whether a given serum is satisfactory for use in production of a conjugate for direct fluorescent antibody tests. Serums with an...

  9. Differential Localization of Complement Component 3 within the Capsular Matrix of Cryptococcus neoformans

    OpenAIRE

    Gates, Marcellene A.; Kozel, Thomas R.

    2006-01-01

    The polysaccharide capsule of Cryptococcus neoformans is a powerful activator of the complement system. The goal of the present study was to assess serum and cellular variables that influence the sites for C3 binding within the capsular matrix. Confocal microscopy using fluorophore-labeled polyclonal anti-C3 and anticapsular monoclonal antibodies and rosetting of fluorescent microspheres coated with anti-C3 were used to identify sites of C3 binding relative to the capsular edge. The results s...

  10. Complement-mediated solubilization of immune complexes. Solubilization inhibition and complement factor levels in SLE patients

    DEFF Research Database (Denmark)

    Baatrup, Gunnar; Petersen, Ivan; Kappelgaard, E;

    1984-01-01

    Thirty-two of 36 serum samples from 19 SLE patients showed reduced capacity to mediate complement-dependent solubilization of immune complexes (IC). SLE patients with nephritis exerted the lowest complement-mediated solubilization capacity (CMSC) whereas sera from patients with inactive disease...

  11. Identification of murine complement receptor type 2.

    OpenAIRE

    Fingeroth, J D; Benedict, M A; Levy, D.N.; Strominger, J L

    1989-01-01

    A rabbit antiserum reactive with the human complement component C3d/Epstein-Barr virus receptor (complement receptor type 2, CR2) immunoprecipitates a Mr 155,000 murine B-cell surface antigen. The apparent molecular weight and cellular distribution of this murine antigen are similar to those of human CR2. Cells expressing the murine protein bind sheep erythrocytes coated with antibody and murine C1-C3d but do not bind Epstein-Barr virus at all. The monospecific antiserum to human CR2 together...

  12. Complement activation and HLA-B27.

    OpenAIRE

    Meri, S.; Partanen, J; Leirisalo-Repo, M; Repo, H

    1988-01-01

    The efficiency of complement activation was studied in sera from HLA-B27 positive and negative subjects (27 with previous yersinia arthritis and 35 controls). Activation of complement with zymosan induced higher mean levels of the anaphylatoxin C3a in HLA-B27 positive sera (mean (SD) 7.40 (1.66) mg/l) than in HLA-B27 negative sera (6.41 (1.79) mg/l). Similarly, higher levels of C3d,g, another C3 breakdown fragment, were obtained in HLA-B27 positive sera after Escherichia coli 0111:B4 lipopoly...

  13. Mesenchymal stromal cells engage complement and complement receptor bearing innate effector cells to modulate immune responses.

    Directory of Open Access Journals (Sweden)

    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.

  14. Fluorescent refrigeration

    Science.gov (United States)

    Epstein, Richard I.; Edwards, Bradley C.; Buchwald, Melvin I.; Gosnell, Timothy R.

    1995-01-01

    Fluorescent refrigeration is based on selective radiative pumping, using substantially monochromatic radiation, of quantum excitations which are then endothermically redistributed to higher energies. Ultimately, the populated energy levels radiatively deexcite emitting, on the average, more radiant energy than was initially absorbed. The material utilized to accomplish the cooling must have dimensions such that the exciting radiation is strongly absorbed, but the fluorescence may exit the material through a significantly smaller optical pathlength. Optical fibers and mirrored glasses and crystals provide this requirement.

  15. Complement activation and inhibition: a delicate balance

    DEFF Research Database (Denmark)

    Sjöberg, A P; Trouw, L A; Blom, A M

    2009-01-01

    Complement is part of the innate immune defence and not only recognizes microbes but also unwanted host molecules to enhance phagocytosis and clearance. This process of opsonisation must be tightly regulated to prevent immunopathology. Endogenous ligands such as dying cells, extracellular matrix ...

  16. Complement activation in chromosome 13 dementias

    DEFF Research Database (Denmark)

    Rostagno, A.; Revesz, T.; Lashley, T.;

    2002-01-01

    (ABri in FBD, ADan in FDD, and Aβ in AD), these disorders are all characterized by the presence of neurofibrillary tangles and parenchymal and vascular amyloid deposits co-localizing with markers of glial activation, suggestive of local inflammation. Proteins of the complement system and their pro...

  17. 21 CFR 866.5240 - Complement components immunological test system.

    Science.gov (United States)

    2010-04-01

    ... complement components C1q, C1r, C1s, C2, C3, C4, C5, C6, C7, C8, and C9, in serum, other body fluids, and... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Complement components immunological test system....5240 Complement components immunological test system. (a) Identification. A complement...

  18. Utilizing complement evasion strategies to design complement-based antibacterial immunotherapeutics: Lessons from the pathogenic Neisseriae.

    Science.gov (United States)

    Ram, Sanjay; Shaughnessy, Jutamas; DeOliveira, Rosane B; Lewis, Lisa A; Gulati, Sunita; Rice, Peter A

    2016-10-01

    Novel therapies are urgently needed to combat the global threat of multidrug-resistant pathogens. Complement forms an important arm of innate defenses against infections. In physiological conditions, complement activation is tightly controlled by soluble and membrane-associated complement inhibitors, but must be selectively activated on invading pathogens to facilitate microbial clearance. Many pathogens, including Neisseria gonorrhoeae and N. meningitidis, express glycans, including N-acetylneuraminic acid (Neu5Ac), that mimic host structures to evade host immunity. Neu5Ac is a negatively charged 9-cabon sugar that inhibits complement, in part by enhancing binding of the complement inhibitor factor H (FH) through C-terminal domains (19 and 20) on FH. Other microbes also bind FH, in most instances through FH domains 6 and 7 or 18-20. Here we describe two strategies to target complement activation on Neisseriae. First, microbial binding domains of FH were fused to IgG Fc to create FH18-20/Fc (binds gonococci) and FH6,7/Fc (binds meningococci). A point mutation in FH domain 19 eliminated hemolysis caused by unmodified FH18-20, but retained binding to gonococci. FH18-20/Fc and FH6,7/Fc mediated complement-dependent killing in vitro and showed efficacy in animal models of gonorrhea and meningococcal bacteremia, respectively. The second strategy utilized CMP-nonulosonate (CMP-NulO) analogs of sialic acid that were incorporated into LOS and prevented complement inhibition by physiologic CMP-Neu5Ac and resulted in attenuated gonococcal infection in mice. While studies to establish the safety of these agents are needed, enhancing complement activation on microbes may represent a promising strategy to treat antimicrobial resistant organisms. PMID:27297292

  19. Analysis of picosecond laser induced fluorescence phenomena in photosynthetic membranes utilizing a master equation approach.

    Science.gov (United States)

    Paillotin, G; Swenberg, C E; Breton, J; Geacintov, N E

    1979-03-01

    A Pauli master equation is formulated and solved to describe the fluorescence quantum yield, phi, and the fluorescence temporal decay curves. F(t), obtained in picosecond laser excitation experiments of photosynthetic systems. It is assumed that the lowering of phi with increasing pulse intensity is due to bimolecular singlet exciton annihilation processes which compete with the monomolecular exciton decay processes; Poisson statistics are taken into account. Calculated curves of phi as a function of the number of photon hits per domain are compared with experimental data, and it is concluded that these domains contain at least two to four connected photosynthetic units (depending on the temperature), where each photosynthetic unit is assumed to contain approximately 300 pigment molecules. It is shown that under conditions of high excitation intensities, the fluorescence decays approximately according to the (time)1/2 law. PMID:262402

  20. Complement Component C3 Binds to Activated Normal Platelets without Preceding Proteolytic Activation and Promotes Binding to Complement Receptor 1

    NARCIS (Netherlands)

    O.A. Hamad; P.H. Nilsson; D. Wouters; J.D. Lambris; K.N. Ekdahl; B. Nilsson

    2010-01-01

    It has been reported that complement is activated on the surface of activated platelets, despite the presence of multiple regulators of complement activation. To reinvestigate the mechanisms by which activated platelets bind to complement components, the presence of complement proteins on the surfac

  1. Trichinella spiralis Paramyosin Binds Human Complement C1q and Inhibits Classical Complement Activation.

    Directory of Open Access Journals (Sweden)

    Ran Sun

    2015-12-01

    Full Text Available Trichinella spiralis expresses paramyosin (Ts-Pmy as a defense mechanism. Ts-Pmy is a functional protein with binding activity to human complement C8 and C9 and thus plays a role in evading the attack of the host's immune system. In the present study, the binding activity of Ts-Pmy to human complement C1q and its ability to inhibit classical complement activation were investigated.The binding of recombinant and natural Ts-Pmy to human C1q were determined by ELISA, Far Western blotting and immunoprecipitation, respectively. Binding of recombinant Ts-Pmy (rTs-Pmy to C1q inhibited C1q binding to IgM and consequently inhibited C3 deposition. The lysis of antibody-sensitized erythrocytes (EAs elicited by the classical complement pathway was also inhibited in the presence of rTs-Pmy. In addition to inhibiting classical complement activation, rTs-Pmy also suppressed C1q binding to THP-1-derived macrophages, thereby reducing C1q-induced macrophages migration.Our results suggest that T. spiralis paramyosin plays an important role in immune evasion by interfering with complement activation through binding to C1q in addition to C8 and C9.

  2. Complementing the sugar code: role of GAGs and sialic acid in complement regulation

    Directory of Open Access Journals (Sweden)

    Alex eLangford-Smith

    2015-02-01

    Full Text Available Sugar molecules play a vital role on both microbial and mammalian cells, where they are involved in cellular communication, govern microbial virulence and modulate host immunity and inflammatory responses. The complement cascade, as part of a host’s innate immune system, is a potent weapon against invading bacteria but has to be tightly regulated to prevent inappropriate attack and damage to host tissues. A number of complement regulators, such as factor H and properdin, interact with sugar molecules, such as glycosaminoglycans and sialic acid, on host and pathogen membranes and direct the appropriate complement response by either promoting the binding of complement activators or inhibitors. The binding of these complement regulators to sugar molecules can vary from location to location, due to their different specificities and because distinct structural and functional subpopulations of sugars are found in different human organs, such as the brain, kidney and eye. This review will cover recent studies that have provided important new insights into the role of glycosaminoglycans and sialic acid in complement regulation and how sugar recognition may be compromised in disease

  3. Fluorescence Correlation Spectroscopy and Nonlinear Stochastic Reaction-Diffusion

    CERN Document Server

    Del Razo, Mauricio J; Qian, Hong; Lin, Guang

    2014-01-01

    The currently existing theory of fluorescence correlation spectroscopy(FCS) is based on the linear fluctuation theory originally developed by Einstein, Onsager, Lax, and others as a phenomenological approach to equilibrium fluctuations in bulk solutions. For mesoscopic reaction-diffusion systems with nonlinear chemical reactions among a small number of molecules, a situation often encountered in single-cell biochemistry, it is expected that FCS time correlation functions of a reaction-diffusion system can deviate from the classic results of Elson and Magde. We first discuss this nonlinear effect for reaction systems without diffusion. For nonlinear stochastic reaction-diffusion systems here are no closed solutions; therefore, stochastic Monte-Carlo simulations are carried out. We show that the deviation is small for a simple bimolecular reaction; the most significant deviations occur when the number of molecules is small and of the same order. Our results show that current linear FCS theory could be adequate ...

  4. Use of X-ray diffraction, molecular simulations, and spectroscopy to determine the molecular packing in a polymer-fullerene bimolecular crystal

    KAUST Repository

    Miller, Nichole Cates

    2012-09-05

    The molecular packing in a polymer: fullerene bimolecular crystal is determined using X-ray diffraction (XRD), molecular mechanics (MM) and molecular dynamics (MD) simulations, 2D solid-state NMR spectroscopy, and IR absorption spectroscopy. The conformation of the electron-donating polymer is significantly disrupted by the incorporation of the electron-accepting fullerene molecules, which introduce twists and bends along the polymer backbone and 1D electron-conducting fullerene channels. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Use of X-ray diffraction, molecular simulations, and spectroscopy to determine the molecular packing in a polymer-fullerene bimolecular crystal

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Nichole Cates; Gysel, Roman; Sweetnam, Sean; McGehee, Michael D. [Department of Materials Science and Engineering, Stanford University, Stanford, CA (United States); Cho, Eunkyung [School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA (United States); School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA (United States); Junk, Matthias J.N.; Chmelka, Bradley F. [Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA (United States); Risko, Chad; Kim, Dongwook; Bredas, Jean-Luc [School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA (United States); Miller, Chad E. [Department of Materials Science and Engineering, Stanford University, Stanford, CA (United States); Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA (United States); Richter, Lee J.; Kline, R. Joseph [National Institute of Standards and Technology, Gaithersburg, MD (United States); Heeney, Martin; McCulloch, Iain [Department of Chemistry, Imperial College London (United Kingdom); Amassian, Aram [King Abdullah University of Science and Technology (KAUST), Physical Sciences and Engineering Division, Thuwal (Saudi Arabia); Acevedo-Feliz, Daniel; Knox, Christopher [King Abdullah University of Science and Technology (KAUST), Visualization Core Laboratory, Thuwal (Saudi Arabia); Hansen, Michael Ryan; Dudenko, Dmytro [Max Planck Institute for Polymer Research, Mainz (Germany); Toney, Michael F. [Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA (United States)

    2012-11-27

    The molecular packing in a polymer: fullerene bimolecular crystal is determined using X-ray diffraction (XRD), molecular mechanics (MM) and molecular dynamics (MD) simulations, 2D solid-state NMR spectroscopy, and IR absorption spectroscopy. The conformation of the electron-donating polymer is significantly disrupted by the incorporation of the electron-accepting fullerene molecules, which introduce twists and bends along the polymer backbone and 1D electron-conducting fullerene channels. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Age-related macular degeneration: Complement in action.

    Science.gov (United States)

    van Lookeren Campagne, Menno; Strauss, Erich C; Yaspan, Brian L

    2016-06-01

    The complement system plays a key role in host-defense against common pathogens but must be tightly controlled to avoid inflammation and tissue damage. Polymorphisms in genes encoding two important negative regulators of the alternative complement pathway, complement factor H (CFH) and complement factor I (CFI), are associated with the risk for Age-Related Macular Degeneration (AMD), a leading cause of vision impairment in the ageing population. In this review, we will discuss the genetic basis of AMD and the potential impact of complement de-regulation on disease pathogenesis. Finally, we will highlight recent therapeutic approaches aimed at controlling complement activation in patients with AMD. PMID:26742632

  7. Genetic Association of the Porcine C9 Complement Component with Hemolytic Complement Activity.

    Science.gov (United States)

    Khoa, D V A; Wimmers, K

    2015-09-01

    The complement system is a part of the natural immune regulation mechanism against invading pathogens. Complement activation from three different pathways (classical, lectin, and alternative) leads to the formation of C5-convertase, an enzyme for cleavage of C5 into C5a and C5b, followed by C6, C7, C8, and C9 in membrane attack complex. The C9 is the last complement component of the terminal lytic pathway, which plays an important role in lysis of the target cells depending on its self-polymerization to form transmembrane channels. To address the association of C9 with traits related to disease resistance, the complete porcine C9 cDNA was comparatively sequenced to detect single nucleotide polymorphisms (SNPs) in pigs of the breeds Hampshire (HS), Duroc (DU), Berlin miniature pig (BMP), German Landrace (LR), Pietrain (PIE), and Muong Khuong (Vietnamese potbelly pig). Genotyping was performed in 417 F2 animals of a resource population (DUMI: DU×BMP) that were vaccinated with Mycoplasma hyopneumoniae, Aujeszky diseases virus and porcine respiratory and reproductive syndrome virus at 6, 14 and 16 weeks of age, respectively. Two SNPs were detected within the third exon. One of them has an amino acid substitution. The European porcine breeds (LR and PIE) show higher allele frequency of these SNPs than Vietnamese porcine breed (MK). Association of the substitution SNP with hemolytic complement activity indicated statistically significant differences between genotypes in the classical pathway but not in the alternative pathway. The interactions between eight time points of measurement of complement activity before and after vaccinations and genotypes were significantly different. The difference in hemolytic complement activity in the both pathways depends on genotype, kind of vaccine, age and the interaction to the other complement components. These results promote the porcine C9 (pC9) as a candidate gene to improve general animal health in the future. PMID:26194222

  8. On Wiener index of graph complements

    Directory of Open Access Journals (Sweden)

    Jaisankar Senbagamalar

    2014-06-01

    Full Text Available Let $G$ be an $(n,m$-graph. We say that $G$ has property $(ast$ if for every pair of its adjacent vertices $x$ and $y$, there exists a vertex $z$, such that $z$ is not adjacent to either $x$ or $y$. If the graph $G$ has property $(ast$, then its complement $overline G$ is connected, has diameter 2, and its Wiener index is equal to $binom{n}{2}+m$, i.e., the Wiener index is insensitive of any other structural details of the graph $G$. We characterize numerous classes of graphs possessing property $(ast$, among which are trees, regular, and unicyclic graphs.

  9. Minimum staff complement: safety in numbers

    International Nuclear Information System (INIS)

    Adequate staffing is an essential safety barrier for event mitigation. For this reason, Canadian nuclear power plant (NPP) licences specify the minimum staff complement (MSC), which is the number and qualifications of staff always required on-site. A systematic analysis and its validation form the basis of the MSC. The analysis and validation demonstrate a licensee is able to control, cool and contain the reactor after any credible event. The CNSC published regulatory guidelines for analyzing the basis for essential staff levels, monitoring compliance with these levels, and controlling MSC changes (G-323). Lessons learned from a full-scale MSC analysis are discussed. (author)

  10. Participial Perception Verb Complements in Old English

    OpenAIRE

    Lowrey Brian

    2014-01-01

    In this paper, I shall examine the complements of perception verbs in Old English involving a noun phrase and a present participle. What kind of perception is described by these structures? Do they evoke the perception of an event, or that of an entity? It will be shown here that there are good reasons to believe that an NP + present participle sequence could function as the equivalent of the traditional “AcI” construction when used with perception verbs. I shall also attempt to determine to ...

  11. Simulation study of the losses and influences of geminate and bimolecular recombination on the performances of bulk heterojunction organic solar cells

    Science.gov (United States)

    Zhu, Jian-Zhuo; Qi, Ling-Hui; Du, Hui-Jing; Chai, Ying-Chun

    2015-10-01

    We use the method of device simulation to study the losses and influences of geminate and bimolecular recombinations on the performances and properties of the bulk heterojunction organic solar cells. We find that a fraction of electrons (holes) in the device are collected by anode (cathode). The direction of the corresponding current is opposite to the direction of photocurrent. And the current density increases with the bias increasing but decreases as bimolecular recombination (BR) or geminate recombination (GR) intensity increases. The maximum power, short circuit current, and fill factor display a stronger dependence on GR than on BR. While the influences of GR and BR on open circuit voltage are about the same. Our studies shed a new light on the loss mechanism and may provide a new way of improving the efficiency of bulk heterojunction organic solar cells. Project supported by the Natural Science Foundation of Hebei Province, China (Grant No. A2012203016), the Science Fund from the Education Department of Hebei Province, China (Grant Nos. QN20131103 and Z2009114), the Doctor Foundation of Yanshan University, China (Grant No. B580), and the Young Teachers' Research Project of Yanshan University, China (Grant No. 13LGB028).

  12. Complement sensitivity of Entamoeba histolytica and various nonpathogenic amoeba species.

    Science.gov (United States)

    Förster, B; Ebert, F; Horstmann, R D

    1994-12-01

    Culture forms of the potentially pathogenic Entamoeba histolytica were compared to those of the nonpathogenic species of E. dispar, E. hartmanni, E. coli, Endolimax nana, and E. moshkovskii regarding the sensitivity to lysis by human complement activated through the alternative pathway. E. dispar was found unique in its complement resistance; all other nonpathogenic isolates resembled E. histolytica in that they were complement sensitive. Thus, a state of complement sensitivity is not a particular property of potentially pathogenic amoebae. PMID:7716404

  13. Complement C3c as a Biomarker in Heart Failure

    OpenAIRE

    Frey, A.; Ertl, G; Angermann, C. E.; Hofmann, U; Störk, S; Frantz, S

    2013-01-01

    Introduction. Experimental data indicates an important role of the innate immune system in cardiac remodeling and heart failure (HF). Complement is a central effector pathway of the innate immune system. Animals lacking parts of the complement system are protected from adverse remodeling. Based on these data, we hypothesized that peripheral complement levels could be a good marker for adverse remodeling and prognosis in patients with HF. Methods and Results. Since complement activation conver...

  14. The Production of Complement Clauses in Children with Language Impairment

    Science.gov (United States)

    Steel, Gillian; Rose, Miranda; Eadie, Patricia

    2016-01-01

    Purpose: The purpose of this research was to provide a comprehensive description of complement-clause production in children with language impairment. Complement clauses were examined with respect to types of complement structure produced, verb use, and both semantic and syntactic accuracy. Method: A group of 17 children with language impairment…

  15. Complement fixation test for the diagnosis of Lyme disease.

    OpenAIRE

    Artsob, H; Huibner, S

    1990-01-01

    Sera from 43 patients were tested for complement-fixing antibodies to Borrelia burgdorferi; these patients included 8 with confirmed Lyme disease, 21 who were serologically positive but not likely to have Lyme disease, and 14 who were serologically negative. Seven individuals, all confirmed Lyme disease patients, had complement-fixing antibodies. Complement fixation may be a useful confirmatory test for Lyme disease.

  16. Hyperbolicity of the complement of plane algebraic curves

    CERN Document Server

    Dethloff, G E; Dethloff, Gerd; Schumacher, Georeg

    1993-01-01

    The paper is a contribution of the conjecture of Kobayashi that the complement o f a generic plain curve of degree at least five is hyperbolic. The main result is that the complement of a generic configuration of three quadr ics is hyperbolic and hyperbolically embedded as well as the complement of two q uadrics and a line.

  17. Early Neoplastic Progression Is Complement Independent

    Directory of Open Access Journals (Sweden)

    Karin E. de Visser

    2004-11-01

    Full Text Available Infiltration of leukocytes into premalignant tissue is a common feature of many epithelial neoplasms and is thought to contribute to cancer development. However, the molecular and cellular regulatory mechanisms underlying activation of innate host responses to enhanced neoplastic cell proliferation are largely unknown. Considering the importance of the complement system in regulating inflammation during acute pathologic tissue remodeling, we examined the functional significance of complement component 3 (C3 as a regulator of inflammatory cell infiltration and activation during malignant progression by using a transgenic mouse model of multistage epithelial carcinogenesis, e.g., HPV16 mice. Whereas abundant deposition of C3 is a characteristic feature of premalignant hyperplasias and dysplasias coincident with leukocyte infiltration in neoplastic tissue, genetic elimination of C3 neither affects inflammatory cell recruitment toward neoplastic skin nor impacts responding pathways downstream of inflammatory cell activation, e.g., keratinocyte hyperproliferation or angiogenesis. Taken together, these data suggest that complementindependent pathways are critical for leukocyte recruitment into neoplastic tissue and leukocytemediated potentiation of tumorigenesis.

  18. Complement Component C3 Binds to Activated Normal Platelets without Preceding Proteolytic Activation and Promotes Binding to Complement Receptor 1

    OpenAIRE

    Osama A Hamad; Nilsson, Per H.; Wouters, Diana; Lambris, John D.; Ekdahl, Kristina N.; Nilsson, Bo

    2010-01-01

    It has been reported that complement is activated on the surface of activated platelets, despite the presence of multiple regulators of complement activation. To reinvestigate the mechanisms by which activated platelets bind to complement components, the presence of complement proteins on the surfaces of nonactivated and thrombin receptor-activating peptide-activated platelets was analyzed by flow cytometry and Western blot analyses. C1q, C4, C3, and C9 were found to bind to thrombin receptor...

  19. Complement analysis 2016: Clinical indications, laboratory diagnostics and quality control.

    Science.gov (United States)

    Prohászka, Zoltán; Nilsson, Bo; Frazer-Abel, Ashley; Kirschfink, Michael

    2016-11-01

    In recent years, complement analysis of body fluids and biopsies, going far beyond C3 and C4, has significantly enhanced our understanding of the disease process. Such expanded complement analysis allows for a more precise differential diagnosis and for critical monitoring of complement-targeted therapy. These changes are a result of the growing understanding of the involvement of complement in a diverse set of disorders. To appreciate the importance of proper complement analysis, it is important to understand the role it plays in disease. Historically, it was the absence of complement as manifested in severe infection that was noted. Since then complement has been connected to a variety of inflammatory disorders, such as autoimmune diseases and hereditary angioedema. While the role of complement in the rejection of renal grafts has been known longer, the significant impact of complement. In certain nephropathies has now led to the reclassification of some rare kidney diseases and an increased role for complement analysis in diagnosis. Even more unexpected is that complement has also been implicated in neural, ophtalmological and dermatological disorders. With this level of involvement in some varied and impactful health issues proper complement testing is clearly important; however, analysis of the complement system varies widely among laboratories. Except for a few proteins, such as C3 and C4, there are neither well-characterized standard preparations nor calibrated assays available. This is especially true for the inter-laboratory variation of tests which assess classical, alternative, or lectin pathway function. In addition, there is a need for the standardization of the measurement of complement activation products that are so critical in determining whether clinically relevant complement activation has occurred in vivo. Finally, autoantibodies to complement proteins (e.g. anti-C1q), C3 and C4 convertases (C3 and C4 nephritic factor) or to regulatory proteins

  20. Every Hilbert space frame has a Naimark complement

    CERN Document Server

    Casazza, Peter G; Mixon, Dustin; Peterson, Jess; Smalyanau, Ihar

    2011-01-01

    Naimark complements for Hilbert space Parseval frames are one of the most fundamental and useful results in the field of frame theory. We will show that actually all Hilbert space frames have Naimark complements which possess all the usual properties for Naimark complements with one notable exception. So these complements can be used for equiangular frames, RIP property, fusion frames etc. Along the way, we will correct a mistake in a recent fusion frame paper where chordal distances for Naimark complements are computed incorrectly.

  1. A vital role for complement in heart disease

    DEFF Research Database (Denmark)

    Lappegård, Knut T; Garred, Peter; Jonasson, Lena;

    2014-01-01

    Heart diseases are common and significant contributors to worldwide mortality and morbidity. During recent years complement mediated inflammation has been shown to be an important player in a variety of heart diseases. Despite some negative results from clinical trials using complement inhibitors......, emerging evidence points to an association between the complement system and heart diseases. Thus, complement seems to be important in coronary heart disease as well as in heart failure, where several studies underscore the prognostic importance of complement activation. Furthermore, patients with atrial...... fibrillation often share risk factors both with coronary heart disease and heart failure, and there is some evidence implicating complement activation in atrial fibrillation. Moreover, Chagas heart disease, a protozoal infection, is an important cause of heart failure in Latin America, and the complement...

  2. The Complement System and Antibody-Mediated Transplant Rejection.

    Science.gov (United States)

    Stites, Erik; Le Quintrec, Moglie; Thurman, Joshua M

    2015-12-15

    Complement activation is an important cause of tissue injury in patients with Ab-mediated rejection (AMR) of transplanted organs. Complement activation triggers a strong inflammatory response, and it also generates tissue-bound and soluble fragments that are clinically useful markers of inflammation. The detection of complement proteins deposited within transplanted tissues has become an indispensible biomarker of AMR, and several assays have recently been developed to measure complement activation by Abs reactive to specific donor HLA expressed within the transplant. Complement inhibitors have entered clinical use and have shown efficacy for the treatment of AMR. New methods of detecting complement activation within transplanted organs will improve our ability to diagnose and monitor AMR, and they will also help guide the use of complement inhibitory drugs. PMID:26637661

  3. Interpain A, a cysteine proteinase from Prevotella intermedia, inhibits complement by degrading complement factor C3.

    Directory of Open Access Journals (Sweden)

    Michal Potempa

    2009-02-01

    Full Text Available Periodontitis is an inflammatory disease of the supporting structures of the teeth caused by, among other pathogens, Prevotella intermedia. Many strains of P. intermedia are resistant to killing by the human complement system, which is present at up to 70% of serum concentration in gingival crevicular fluid. Incubation of human serum with recombinant cysteine protease of P. intermedia (interpain A resulted in a drastic decrease in bactericidal activity of the serum. Furthermore, a clinical strain 59 expressing interpain A was more serum-resistant than another clinical strain 57, which did not express interpain A, as determined by Western blotting. Moreover, in the presence of the cysteine protease inhibitor E64, the killing of strain 59 by human serum was enhanced. Importantly, we found that the majority of P. intermedia strains isolated from chronic and aggressive periodontitis carry and express the interpain A gene. The protective effect of interpain A against serum bactericidal activity was found to be attributable to its ability to inhibit all three complement pathways through the efficient degradation of the alpha-chain of C3 -- the major complement factor common to all three pathways. P. intermedia has been known to co-aggregate with P. gingivalis, which produce gingipains to efficiently degrade complement factors. Here, interpain A was found to have a synergistic effect with gingipains on complement degradation. In addition, interpain A was able to activate the C1 complex in serum, causing deposition of C1q on inert and bacterial surfaces, which may be important at initial stages of infection when local inflammatory reaction may be beneficial for a pathogen. Taken together, the newly characterized interpain A proteinase appears to be an important virulence factor of P. intermedia.

  4. A vital role for complement in heart disease.

    Science.gov (United States)

    Lappegård, Knut T; Garred, Peter; Jonasson, Lena; Espevik, Terje; Aukrust, Pål; Yndestad, Arne; Mollnes, Tom E; Hovland, Anders

    2014-10-01

    Heart diseases are common and significant contributors to worldwide mortality and morbidity. During recent years complement mediated inflammation has been shown to be an important player in a variety of heart diseases. Despite some negative results from clinical trials using complement inhibitors, emerging evidence points to an association between the complement system and heart diseases. Thus, complement seems to be important in coronary heart disease as well as in heart failure, where several studies underscore the prognostic importance of complement activation. Furthermore, patients with atrial fibrillation often share risk factors both with coronary heart disease and heart failure, and there is some evidence implicating complement activation in atrial fibrillation. Moreover, Chagas heart disease, a protozoal infection, is an important cause of heart failure in Latin America, and the complement system is crucial for the protozoa-host interaction. Thus, complement activation appears to be involved in the pathophysiology of a diverse range of cardiac conditions. Determination of the exact role of complement in the various heart diseases will hopefully help to identify patients that might benefit from therapeutic complement intervention. PMID:25037633

  5. The influence of the "cage" effect on the mechanism of reversible bimolecular multistage chemical reactions proceeding from different sites in solutions.

    Science.gov (United States)

    Doktorov, Alexander B

    2016-08-28

    Manifestations of the "cage" effect at the encounters of reactants have been theoretically treated on the example of multistage reactions (including bimolecular exchange reactions as elementary stages) proceeding from different active sites in liquid solutions. It is shown that for reactions occurring near the contact of reactants, consistent consideration of quasi-stationary kinetics of such multistage reactions (possible in the framework of the encounter theory only) can be made on the basis of chemical concepts of the "cage complex," just as in the case of one-site model described in the literature. Exactly as in the one-site model, the presence of the "cage" effect gives rise to new channels of reactant transformation that cannot result from elementary event of chemical conversion for the given reaction mechanism. Besides, the multisite model demonstrates new (as compared to one-site model) features of multistage reaction course. PMID:27586911

  6. Measurement of the rate of bimolecular electron spin relaxation between pairs of reactive radicals using time-resolved electron spin-echo spectroscopy

    International Nuclear Information System (INIS)

    The time-resolved electron spin echo (ESE) method has been employed to measure the bimolecular contribution to electron spin relaxation in the acetate radical xCH2CO-2, formed by pulse radiolysis. Time-resolved ESE signals from solutions containing up to 4 x 10-4 M initial radical concentrations were analyzed using Bloch equations modified to include the effects of strong Heisenberg exchange, chemical reaction, and CIDEP. It is found that the electron exchange rate is approx.3 times faster than the chemical reaction rate, contrary to a simple model involving only statistical factors which predicts equal rates for the two processes. It is also found that the CIDEP enhancement factor is independent of initial radical concentration over the ten fold range of concentrations studied

  7. Fluorescence detection: SPIE volume 743

    International Nuclear Information System (INIS)

    This book contains proceedings arranged into four sessions. They are: Fluorescence spectroscopic techniques; Fluorescence in analysis and materials characterization; Fluorescence in medicine and biochemistry; and Fluorescence in criminalistics

  8. Fluorescence detection: SPIE volume 743

    Energy Technology Data Exchange (ETDEWEB)

    Menzel, E.R.

    1987-01-01

    This book contains proceedings arranged into four sessions. They are: Fluorescence spectroscopic techniques; Fluorescence in analysis and materials characterization; Fluorescence in medicine and biochemistry; and Fluorescence in criminalistics.

  9. Complement, a target for therapy in inflammatory and degenerative diseases.

    Science.gov (United States)

    Morgan, B Paul; Harris, Claire L

    2015-12-01

    The complement system is a key innate immune defence against infection and an important driver of inflammation; however, these very properties can also cause harm. Inappropriate or uncontrolled activation of complement can cause local and/or systemic inflammation, tissue damage and disease. Complement provides numerous options for drug development as it is a proteolytic cascade that involves nine specific proteases, unique multimolecular activation and lytic complexes, an arsenal of natural inhibitors, and numerous receptors that bind to activation fragments. Drug design is facilitated by the increasingly detailed structural understanding of the molecules involved in the complement system. Only two anti-complement drugs are currently on the market, but many more are being developed for diseases that include infectious, inflammatory, degenerative, traumatic and neoplastic disorders. In this Review, we describe the history, current landscape and future directions for anti-complement therapies. PMID:26493766

  10. C-Reactive Protein Activates Complement in Infarcted Human Myocardium

    OpenAIRE

    Nijmeijer, Remco; Lagrand, Wim K.; Lubbers, Yvonne T. P.; Visser, Cees A.; Meijer, Chris J.L.M.; Niessen, Hans W. M.; Hack, C. Erik

    2003-01-01

    Circulating levels of C-reactive protein (CRP) constitute a cardiovascular risk marker. Immunohistochemical studies have revealed co-localization of CRP and activated complement in human infarcted myocardium suggesting CRP to enhance inflammation in ischemic myocardium by inducing local complement activation. The aim was to establish whether CRP activates complement in infarcted human myocardium and to assess the relationship between this activation and the duration of infarction. Myocardial ...

  11. Differential Complement Resistance Mediates Virulence of Haemophilus influenzae Type b

    OpenAIRE

    Sutton, Ann; Schneerson, Rachel; Kendall-Morris, Saundra; Robbins, John B.

    1982-01-01

    Studies were undertaken to gain insight into the virulence of type b in contrast to the other Haemophilus influenzae capsular types. A relationship was found between the comparative virulence of H. influenzae types in humans and their resistance to the bactericidal effect of antibody-free complement. Type b was most resistant to the bactericidal effect of complement. The other types could be divided into three groups based upon their susceptibility to complement; this grouping was also relate...

  12. Microbes Bind Complement Inhibitor Factor H via a Common Site

    OpenAIRE

    Meri, T.; Amdahl, H.; Lehtinen, M. J.; Hyvärinen, S.; McDowell, J.V.; Bhattacharjee, A.; Meri, S.; Marconi, R.; Goldman, A; Jokiranta, T. S.

    2013-01-01

    To cause infections microbes need to evade host defense systems, one of these being the evolutionarily old and important arm of innate immunity, the alternative pathway of complement. It can attack all kinds of targets and is tightly controlled in plasma and on host cells by plasma complement regulator factor H (FH). FH binds simultaneously to host cell surface structures such as heparin or glycosaminoglycans via domain 20 and to the main complement opsonin C3b via domain 19. Many pathogenic ...

  13. Efficacy of Targeted Complement Inhibition in Experimental C3 Glomerulopathy

    OpenAIRE

    Ruseva, Marieta M.; Peng, Tao; Lasaro, Melissa A.; Bouchard, Keith; Liu-Chen, Susan; Sun, Fang; Yu, Zhao-Xue; Marozsan, Andre; Wang, Yi; Pickering, Matthew C.

    2015-01-01

    C3 glomerulopathy refers to renal disorders characterized by abnormal accumulation of C3 within the kidney, commonly along the glomerular basement membrane (GBM). C3 glomerulopathy is associated with complement alternative pathway dysregulation, which includes functional defects in complement regulator factor H (FH). There is no effective treatment for C3 glomerulopathy. We investigated the efficacy of a recombinant mouse protein composed of domains from complement receptor 2 (CR2) and FH (CR...

  14. The Appositive NP-Complement Clause and Restructuring

    OpenAIRE

    Inada, Shun'ichiro

    2005-01-01

    This paper examines properties of Japanese Af-ga-aru construction involving an appositive NP-complement clause and presents a new approach to restructuring. The new analysis can explain the monoclausality of. sentences with an appositive NP-complement as well as that of restructuring constructions with a VP-complement. I will show that the former construction has the same properties as the latter while the former cannot be restructured at base structure or by overt operations based on two poi...

  15. The Complement of Normal Fuzzy Numbers: An Exposition

    Directory of Open Access Journals (Sweden)

    Mamoni Dhar

    2013-07-01

    Full Text Available In this article, our main intention is to revisit the existing definition of complementation of fuzzy sets and thereafter various theories associated with it are also commented on. The main contribution of this paper is to suggest a new definition of complementation of fuzzy sets on the basis of reference function. Some other results have also been introduced whenever possible by using this new definition of complementation.

  16. Mobile MSN Messenger: Still a Complement?

    Directory of Open Access Journals (Sweden)

    Marcus Nyberg

    2008-10-01

    Full Text Available In order to understand how mobile instant messaging services can fit into the users’ current communication behavior, Ericsson Research performed a qualitative user study in Sweden in May 2007. The results showed that the respondents were positive towards (free of charge mobile MSN Messenger and perceived it as an ex¬tension of the computer-based version that could be used anywhere. However, although MSN Messenger on the com¬puter definitely was considered as a ‘must-have’ application, the mobile version was only perceived as a ‘nice-to-have’ application and a complement to text mes¬saging (SMS. Almost one year later, in April 2008, Ericsson Research performed a short qualita¬tive follow-up study with the same set of respondents to un¬derstand if and how the mobile MSN Messenger usage had changed. The results actually revealed that none of the re¬spondents used mobile MSN Messenger anymore as the application no longer was free of charge. On a general level, the study highlights important considera¬tions when intro¬ducing computer-based concepts and Internet services in a mo¬bile environment.

  17. Altmetrics - a complement to conventional metrics.

    Science.gov (United States)

    Melero, Remedios

    2015-01-01

    Emerging metrics based on article-level does not exclude traditional metrics based on citations to the journal, but complements them. Both can be employed in conjunction to offer a richer picture of an article use from immediate to long terms. Article-level metrics (ALM) is the result of the aggregation of different data sources and the collection of content from multiple social network services. Sources used for the aggregation can be broken down into five categories: usage, captures, mentions, social media and citations. Data sources depend on the tool, but they include classic metrics indicators based on citations, academic social networks (Mendeley, CiteULike, Delicious) and social media (Facebook, Twitter, blogs, or Youtube, among others). Altmetrics is not synonymous with alternative metrics. Altmetrics are normally early available and allow to assess the social impact of scholarly outputs, almost at the real time. This paper overviews briefly the meaning of altmetrics and describes some of the existing tools used to apply this new metrics: Public Library of Science--Article-Level Metrics, Altmetric, Impactstory and Plum. PMID:26110028

  18. Complement sequestration in ischemic baboon myocardium

    International Nuclear Information System (INIS)

    Complement-mediated myocardial tissue injury following ischemia has proposed. In the present study, sequestration of radiolabeled human C5 was estimated in baboon myocardial tissue samples obtained 24 hr following ligation of the left anterior descending coronary artery (n=5 baboons). 125I-C5 and 131I-albumin were intravenously administered 24 hr prior to the ligation procedure; 99T-albumin was injected just prior to sacrifice and used to estimate tissue blood volume. Alternating myocardial tissue samples were evaluated for creatine kinase (CK) content after homogenization or for histology after fixation in neutral buffered formalin. 99Tc, 125I, and 131I were determined in all samples. Both C5 and albumin were sequestered in formalin-fixed tissues. No 131I-albumin was retained in any pellet following homogenization whereas, 125I-C5 was present in tissue pellets obtained from ischemic regions. 125I-C5 bound to myocardium was correlated to the extent of the tissue injury, i.e., as myocardial CK decreased, 125I-C5 sequestration increased. Thus, C5 accumulates in ischemic myocardium, and, in contrast to albumin which is present as a consequence of tissue edema following tissue injury, appears to be tissue-bound

  19. TWO RELATED CASES OF PRIMARY COMPLEMENT DEFICIENCY

    Directory of Open Access Journals (Sweden)

    A. Farhoudi

    2003-06-01

    Full Text Available Primary complement deficiencies are rare and two related patients are reported here. The first patient is a 41- year- old man with eighteen episodes of pneumo¬coccal meningitis and other purulent infections. The serum C3 level was checked at three separate times, showing that this was a primary C3 deficient case; other immunological tests were however normal. This patient now takes prophylactic antibiotics and the meningitis has not recurred, but he does have glomerulone¬phritis. The second case is a 40 - year-old woman with repeated episodes of orofacial and laryngeal edema and dyspnea. The serum C1INH levels were 4.3 to 7 mg/dL which were very low compared with normal healthy subjects (C,INH was 40-50 mg/dL in ten normal controls and C4 was lower than normal but other immunological tests were normal. Other causes of angioedema such as lymphoproliferative disorders were excluded. She had hereditary angioedema with¬out a family background. The condition may be due to genetic mutation. The angioedema was controlled with Danazol and Stanasol. As our patients are re¬lated, this may suggest a genetic relationship between these two disorders.

  20. The complement C3 protein family in invertebrates

    OpenAIRE

    Nonaka, M

    2011-01-01

    Complement C3 plays a pivotal role in the innate immune system of mammals as the central component of the complement system essential for its activation mechanism and effecter function. C3 has a unique intra-chain thioester bond that is shared by some complement and non-complement proteins forming a thioester protein (TEP) family. Phylogenetic analysis of TEP family genes of vertebrates and invertebrates revealed that the TEP family is divided into two subfamilies, the C3 subfamily and the al...

  1. Evasion of Complement-Mediated Lysis and Complement C3 Deposition Are Regulated by Francisella tularensis Lipopolysaccharide O Antigen1

    OpenAIRE

    Clay, Corey D.; Soni, Shilpa; Gunn, John S.; Schlesinger, Larry S.

    2008-01-01

    The bacterium Francisella tularensis (Ft) is a potential weapon of bioterrorism when aerosolized. Macrophage infection is necessary for disease progression and efficient phagocytosis by human macrophages requires serum opsonization by complement. Microbial complement activation leads to surface deposition of a highly regulated protein complex resulting in opsonization or membrane lysis. The nature of complement component C3 deposition, i.e., C3b (opsonization and lysis) or C3bi (opsonization ...

  2. Structure of Compstatin in Complex with Complement Component C3c Reveals a New Mechanism of Complement Inhibition

    OpenAIRE

    Janssen, B.J.C.; Halff, E.F.; LAMBRIS, J. D.; Gros, P

    2007-01-01

    Undesired complement activation is a major cause of tissue injury in various pathological conditions and contributes to several immune complex diseases. Compstatin, a 13-residue peptide, is an effective inhibitor of the activation of complement component C3 and thus blocks a central and crucial step in the complement cascade. The precise binding site on C3, the structure in the bound form, and the exact mode of action of compstatin are unknown. Here we present the crystal structure of compsta...

  3. In vitro biosynthesis of complement protein D

    Energy Technology Data Exchange (ETDEWEB)

    Barnum, S.R.

    1985-01-01

    The aim of this study was twofold: to determine site(s) of complement protein D biosynthesis and to examine D biosynthesis with respect to the kinetics of D secretion, the post-translational modification of D and the tissue-specific differences in D secretion and processing. Antigenic D was detected in the culture supernatants of two cell lines, U937 and HepG2, and adherent blood monocytes by a solid-phase radioimmunoassay. D secreted by U937 cells was hemolytically active with a specific activity comparable to D in serum. De novo synthesis of D by U937 cells was demonstrated with the use of cycloheximide. Biosynthetic labeling using /sup 35/S labeled methionine or cysteine, followed by immunoprecipitation demonstrated a single d band intra- and extra-cellularly in all three cell types as analyzed by SDS-PAGE and auto-radiography. Elevated serum D levels in individuals with IgA nephropathy led to studies on the D levels in serum and urine of individuals with chronic renal failure and an individual with Fanconi's syndrome. The former group had elevated serum D levels, compared to normals, and insignificant levels of D in their urine while the patient with Fanconi's syndrome had normal serum D levels but markedly elevated urinary D levels. These studies demonstrate that the monocyte and hepatocyte are both sites of D synthesis and that there are no apparent differences in the secretion rates and processing of D produced by these cell types. The results also suggest that D is not synthesized or secreted as a precursor molecule. Additionally, these studies suggest that the kidney is a major site of D catabolism.

  4. Demand Heterogeneity and the Adoption of Platform Complements

    NARCIS (Netherlands)

    J. Rietveld (Joost); J.P. Eggers

    2016-01-01

    textabstractThis paper offers a demand-based theory of how platform maturity affects the adoption of platform complements. We argue that differences between early and late adopters of the platform include willingness to pay for the platform-and-complement bundle, risk preferences, preference for nov

  5. Defining the complement biomarker profile of c3 glomerulopathy

    DEFF Research Database (Denmark)

    Zhang, Yuzhou; Nester, Carla M; Martin, Bertha;

    2014-01-01

    , although a full description of the disease spectrum remains to be determined. This study sought to validate and define the association of complement dysregulation with C3G and to determine whether specific complement pathway abnormalities could inform disease definition. DESIGN, SETTING, PARTICIPANTS...

  6. Schur complements of matrices with acyclic bipartite graphs

    DEFF Research Database (Denmark)

    Britz, Thomas Johann; Olesky, D.D.; van den Driessche, P.

    2005-01-01

    Bipartite graphs are used to describe the generalized Schur complements of real matrices having nos quare submatrix with two or more nonzero diagonals. For any matrix A with this property, including any nearly reducible matrix, the sign pattern of each generalized Schur complement is shown...

  7. Properties of complements in the lattice of convergence structures

    OpenAIRE

    C. V. Riecke

    1980-01-01

    Relative complements and differences are investigated for several convergence structure lattices, especially the lattices of Kent convergence structures and the lattice of pretopologies. Convergence space properties preserved by relative complementation are studied. Mappings of some convergence structure lattices into related lattices of lattice homomorphisms are considered.

  8. Molecular mechanisms of complement activation, regulation and evasion

    NARCIS (Netherlands)

    Wu, J.

    2012-01-01

    The complement system of our immune defense can rapidly recognize and eliminate pathogens in blood. Activation of complement depends on enzymatic complexes, known as C3 convertases, which are short lived and dissociate irreversibly. Staphylococcus aureus secretes a small protein (named SCIN) that su

  9. Multiple forms of complement C3 in trout that differ in binding to complement activators.

    OpenAIRE

    Sunyer, J O; Zarkadis, I K; Sahu, A.; LAMBRIS, J. D.

    1996-01-01

    In all other species analyzed to date, the functionally active form of complement component C3 exists as the product of a single gene. We have now identified and characterized three functional C3 proteins (C3-1, C3-3, and C3-4) in trout that are the products of at least two distinct C3 genes. All three proteins are composed of an alpha-and a beta-chain and contain a thioester bond in the alpha-chain. However, they differ in their electrophoretic mobility, glycosylation, reactivity with monosp...

  10. Influence of chemotherapeutic treatment on the complement system

    International Nuclear Information System (INIS)

    The complement system as part of the innate immunity is usually regarded as defence system against intruding pathogens and to aid in the removal of immune complexes. In this regard the complement system attracted interest as effector system in increasing the efficiency of antitumour monoclonal antibodies in cancer research. So far, another function of the complement system, the opsonisation of the body's own apoptotic cells with complement components for efficient phagocytosis has received little attention. In a preliminary study, the neoadjuvant combination chemotherapy epirubicin/docetaxel resulted in distinct quantitative changes in the complement components C3 and C4 in the plasma of breast cancer patients within 24 hours after the initial dose. The first aim of the present thesis was the investigation of complement components as biomarkers for the prediction of response to the initial dose of epirubicin/docetaxel in breast cancer patients. Secondly, the applicability of complement components as general markers for the action of chemotherapeutic agents was analysed. In the first part, plasma samples of 25 breast cancer patients were analysed immediately before and 24 hours after the initial chemotherapeutic dose by two-dimensional differential gel electrophoresis (2D-DIGE). Two protein spots belonging to complement C3 showed a correlation with the response to treatment after six cycles of chemotherapy. This result demonstrates that complement C3 is a potential novel predictive biomarker for epirubicin/docetaxel therapy. In the second part of this thesis, the Jurkat T lymphocyte tumour cell line was treated with six different chemotherapeutic agents and deposition of the initiator molecule of the classical complement pathway C1q and the activation fragment C3d on the tumour cells was analysed by flow cytometry. The analysis revealed that deposition of complement C1q and C3d occurred predominantly on late apoptotic cells with a weak DNA staining signal regardless

  11. Signal Improvement Strategies for Fluorescence Detection of Biomacromolecules.

    Science.gov (United States)

    Luan, Chengxin; Yang, Zixue; Chen, Baoan

    2016-05-01

    For analysis of biomacromolecules, a sensitive, specified and reliable method is indispensable. Fluorescent dyes or fluorophores have been widely used as mediums to obtain readout signals in various assays or bioimaging because of their versatilities such as biocompatibility. Those fluorescent dyes based techniques manipulate many molecular interactions for analysis of biomacromolecules including antibody-protein interaction, base complementation, glycan-lectin interaction, etc. The strategies to manipulate those molecular interactions are various and always updating due to the development of biotechnological tools and instruments. In this minireview, we summarize the state of the art of signal improvement techniques for fluorescence detection of biomacromolecules especially proteins and nucleic acids. We focus on the principle and mechanism of those techniques for fluorescence detection of biomacromolecules. We also discuss the future trend of the techniques for fluorescence detection of biomacromolecules. PMID:27063869

  12. Novel Evasion Mechanisms of the Classical Complement Pathway.

    Science.gov (United States)

    Garcia, Brandon L; Zwarthoff, Seline A; Rooijakkers, Suzan H M; Geisbrecht, Brian V

    2016-09-15

    Complement is a network of soluble and cell surface-associated proteins that gives rise to a self-amplifying, yet tightly regulated system with fundamental roles in immune surveillance and clearance. Complement becomes activated on the surface of nonself cells by one of three initiating mechanisms known as the classical, lectin, and alternative pathways. Evasion of complement function is a hallmark of invasive pathogens and hematophagous organisms. Although many complement-inhibition strategies hinge on hijacking activities of endogenous complement regulatory proteins, an increasing number of uniquely evolved evasion molecules have been discovered over the past decade. In this review, we focus on several recent investigations that revealed mechanistically distinct inhibitors of the classical pathway. Because the classical pathway is an important and specific mediator of various autoimmune and inflammatory disorders, in-depth knowledge of novel evasion mechanisms could direct future development of therapeutic anti-inflammatory molecules. PMID:27591336

  13. Physicochemical signatures of nanoparticle-dependent complement activation

    Science.gov (United States)

    Thomas, Dennis G.; Chikkagoudar, Satish; Heredia-Langner, Alejandro; Tardiff, Mark F.; Xu, Zhixiang; Hourcade, Dennis E.; Pham, Christine T. N.; Lanza, Gregory M.; Weinberger, Kilian Q.; Baker, Nathan A.

    2014-01-01

    Nanoparticles are potentially powerful therapeutic tools that have the capacity to target drug payloads and imaging agents. However, some nanoparticles can activate complement, a branch of the innate immune system, and cause adverse side-effects. Recently, we employed an in vitro hemolysis assay to measure the serum complement activity of perfluorocarbon nanoparticles that differed by size, surface charge, and surface chemistry, quantifying the nanoparticle-dependent complement activity using a metric called Residual Hemolytic Activity (RHA). In the present work, we have used a decision tree learning algorithm to derive the rules for estimating nanoparticle-dependent complement response based on the data generated from the hemolytic assay studies. Our results indicate that physicochemical properties of nanoparticles, namely, size, polydispersity index, zeta potential, and mole percentage of the active surface ligand of a nanoparticle, can serve as good descriptors for prediction of nanoparticle-dependent complement activation in the decision tree modeling framework.

  14. The alternative pathway of complement and the thrombotic microangiopathies.

    Science.gov (United States)

    Teoh, Chia Wei; Riedl, Magdalena; Licht, Christoph

    2016-04-01

    Thrombotic microangiopathies (TMA) are disorders defined by microangiopathic hemolytic anemia, non-immune thrombocytopenia and have multi-organ involvement including the kidneys, brain, gastrointestinal, respiratory tract and skin. Emerging evidence points to the central role of complement dysregulation in leading to microvascular endothelial injury which is crucial for the development of TMAs. This key insight has led to the development of complement-targeted therapy. Eculizumab is an anti-C5 monoclonal antibody, which has revolutionized the treatment of atypical hemolytic uremic syndrome. Several other anti-complement therapeutic agents are currently in development, offering a potential armamentarium of therapies available to treat complement-mediated TMAs. The development of sensitive, reliable and easy to perform assays to monitor complement activity and therapeutic efficacy will be key to devising an individualized treatment regime with the potential of safely weaning or discontinuing treatment in the appropriate clinical setting. PMID:27160864

  15. Physicochemical signatures of nanoparticle-dependent complement activation

    International Nuclear Information System (INIS)

    Nanoparticles are potentially powerful therapeutic tools that have the capacity to target drug payloads and imaging agents. However, some nanoparticles can activate complement, a branch of the innate immune system, and cause adverse side-effects. Recently, we employed an in vitro hemolysis assay to measure the serum complement activity of perfluorocarbon nanoparticles that differed by size, surface charge, and surface chemistry, quantifying the nanoparticle-dependent complement activity using a metric called Residual Hemolytic Activity (RHA). In the present work, we have used a decision tree learning algorithm to derive the rules for estimating nanoparticle-dependent complement response based on the data generated from the hemolytic assay studies. Our results indicate that physicochemical properties of nanoparticles, namely, size, polydispersity index, zeta potential, and mole percentage of the active surface ligand of a nanoparticle, can serve as good descriptors for prediction of nanoparticle-dependent complement activation in the decision tree modeling framework. (papers)

  16. The problems of the complex sentences with complements in Bulgarian

    Directory of Open Access Journals (Sweden)

    Nicolova Ruselina

    2008-01-01

    Full Text Available The investigation of the complex sentences with complements in Bulgarian is a multifactor analysis, which has to take into account the following issues: a the lexical meaning of the main predicate, which determines the meaning of the complement in general; b the grammatical meanings of the main predicate - person (a special role plays the opposition between the speaker and the other participants in communication, number, tense, mood, evidentiality affirmativity or negation; c the functions of the linking words - complementizers, particles, interrogatives, relatives; d the meaning of the complement and its related presuppositions or implications (if any, its modality, its illocutionary force, its formal structure, its syntactic position in the complex sentence; e the combinatorial potential of the matrix sentence and the complement in both aspects - semantic and formal.

  17. Complement system part I - molecular mechanisms of activation and regulation

    Directory of Open Access Journals (Sweden)

    Nicolas eMerle

    2015-06-01

    Full Text Available Complement is a complex innate immune surveillance system, playing a key role in defense against pathogens and in host homeostasis. The complement system is initiated by conformational changes in recognition molecular complexes upon sensing danger signals. The subsequent cascade of enzymatic reactions is tightly regulated to assure that complement is activated only at specific locations requiring defense against pathogens, thus avoiding host tissue damage. Here we discuss the recent advances describing the molecular and structural basis of activation and regulation of the complement pathways and their implication on physiology and pathology. This article will review the mechanisms of activation of alternative, classical and lectin pathways, the formation of C3 and C5 convertases, the action of anaphylatoxins and the membrane attack complex. We will also discuss the importance of structure-function relationships using the example of atypical hemolytic uremic syndrome. Lastly we will discuss the development and benefits of therapies using complement inhibitors.

  18. Structure of Compstatin in Complex with Complement Component C3c Reveals a New Mechanism of Complement Inhibition

    NARCIS (Netherlands)

    Janssen, B.J.C.; Halff, E.F.; Lambris, J.D.; Gros, P.

    2007-01-01

    Undesired complement activation is a major cause of tissue injury in various pathological conditions and contributes to several immune complex diseases. Compstatin, a 13-residue peptide, is an effective inhibitor of the activation of complement component C3 and thus blocks a central and crucial step

  19. Is the flower fluorescence relevant in biocommunication?

    Science.gov (United States)

    Iriel, Analía; Lagorio, María Gabriela

    2010-10-01

    Flower fluorescence has been previously proposed as a potential visual signal to attract pollinators. In this work, this point was addressed by quantitatively measuring the fluorescence quantum yield ( Φ f) for flowers of Bellis perennis (white, yellow, pink, and purple), Ornithogalum thyrsoides (petals and ovaries), Limonium sinuatum (white and yellow), Lampranthus productus (yellow), Petunia nyctaginiflora (white), Bougainvillea spectabilis (white and yellow), Antirrhinum majus (white and yellow), Eustoma grandiflorum (white and blue), Citrus aurantium (petals and stigma), and Portulaca grandiflora (yellow). The highest values were obtained for the ovaries of O. thyrsoides ( Φ f = 0.030) and for Citrus aurantium petals ( Φ f = 0.014) and stigma ( Φ f = 0.013). Emitted photons as fluorescence were compared with reflected photons. It was concluded that the fluorescence emission is negligible compared to the reflected light, even for the most fluorescent samples, and it may not be considered as an optical signal in biocommunication. The work was complemented with the calculation of quantum catches for each studied flower species to describe the visual sensitization of eye photoreceptors.

  20. More than just immune evasion: Hijacking complement by Plasmodium falciparum.

    Science.gov (United States)

    Schmidt, Christoph Q; Kennedy, Alexander T; Tham, Wai-Hong

    2015-09-01

    Malaria remains one of the world's deadliest diseases. Plasmodium falciparum is responsible for the most severe and lethal form of human malaria. P. falciparum's life cycle involves two obligate hosts: human and mosquito. From initial entry into these hosts, malaria parasites face the onslaught of the first line of host defence, the complement system. In this review, we discuss the complex interaction between complement and malaria infection in terms of hosts immune responses, parasite survival and pathogenesis of severe forms of malaria. We will focus on the role of complement receptor 1 and its associated polymorphisms in malaria immune complex clearance, as a mediator of parasite rosetting and as an entry receptor for P. falciparum invasion. Complement evasion strategies of P. falciparum parasites will also be highlighted. The sexual forms of the malaria parasites recruit the soluble human complement regulator Factor H to evade complement-mediated killing within the mosquito host. A novel evasion strategy is the deployment of parasite organelles to divert complement attack from infective blood stage parasites. Finally we outline the future challenge to understand the implications of these exploitation mechanisms in the interplay between successful infection of the host and pathogenesis observed in severe malaria. PMID:25816986

  1. Fundamentals of fluorescence and fluorescence microscopy.

    Science.gov (United States)

    Wolf, David E

    2013-01-01

    This chapter discusses the fundamental physics of fluorescence. The application of fluorescence to microscopy represents an important transition in the development of microscopy, particularly as it applies to biology. It enables quantitating the amounts of specific molecules within a cell, determining whether molecules are complexing on a molecular level, measuring changes in ionic concentrations within cells and organelles, and measuring molecular dynamics. This chapter also discusses the issues important to quantitative measurement of fluorescence and focuses on four of quantitative measurements of fluorescence--boxcar-gated detection, streak cameras, photon correlation, and phase modulation. Although quantitative measurement presents many pitfalls to the beginner, it also presents significant opportunities to one skilled in the art. This chapter also examines how fluorescence is measured in the steady state and time domain and how fluorescence is applied in the modern epifluorescence microscope. PMID:23931503

  2. Role of the lectin complement pathway in kidney transplantation.

    Science.gov (United States)

    Farrar, Conrad A; Zhou, Wuding; Sacks, Steven H

    2016-10-01

    In the last 15 years two major advances in the role of complement in the kidney transplant have come about. The first is that ischaemia reperfusion injury and its profound effect on transplant outcome is dependent on the terminal product of complement activation, C5b-9. The second key observation relates to the function of the small biologically active fragments C3a and C5a released by complement activation in increasing antigen presentation and priming the T cell response that results in transplant rejection. In both cases local synthesis of C3 principally by the renal tubule cells plays an essential role that overshadows the role of the circulating pool of C3 generated largely by hepatocyte synthesis. More recent efforts have investigated the molecules expressed by renal tissue that can trigger complement activation. These have revealed a prominent effect of collectin-11 (CL-11), a soluble C-type lectin that is expressed in renal tissue and aligns with its major ligand L-fucose at sites of complement activation following ischaemic stress. Biochemical studies have shown that interaction between CL-11 and L-fucose results in complement activation by the lectin complement pathway, precisely targeting the innate immune response to the ischaemic tubule surface. Therapeutic approaches to reduce inflammatory and immune stimulation in ischaemic kidney have so far targeted C3 or its activation products and several are in clinical trials. The finding that lectin-fucose interaction is an important trigger of lectin pathway complement activation within the donor organ opens up further therapeutic targets where intervention could protect the donor kidney against complement. PMID:27286717

  3. Analyzing Intracellular Binding and Diffusion with Continuous Fluorescence Photobleaching

    Science.gov (United States)

    Wachsmuth, Malte; Weidemann, Thomas; Müller, Gabriele; Hoffmann-Rohrer, Urs W.; Knoch, Tobias A.; Waldeck, Waldemar; Langowski, Jörg

    2003-01-01

    Transport and binding of molecules to specific sites are necessary for the assembly and function of ordered supramolecular structures in cells. For analyzing these processes in vivo, we have developed a confocal fluorescence fluctuation microscope that allows both imaging of the spatial distribution of fluorescent molecules with confocal laser scanning microscopy and probing their mobility at specific positions in the cell with fluorescence correlation spectroscopy and continuous fluorescence photobleaching (CP). Because fluorescence correlation spectroscopy is restricted to rapidly diffusing particles and CP to slower processes, these two methods complement each other. For the analysis of binding-related contributions to mobility we have derived analytical expressions for the temporal behavior of CP curves from which the bound fraction and/or the dissociation rate or residence time at binding sites, respectively, can be obtained. In experiments, we investigated HeLa cells expressing different fluorescent proteins: Although enhanced green fluorescent protein (EGFP) shows high mobility, fusions of histone H2B with the yellow fluorescent protein are incorporated into chromatin, and these nuclei exhibit the presence of a stably bound and a freely diffusing species. Nonpermanent binding was found for mTTF-I, a transcription termination factor for RNA polymerase I, fused with EGFP. The cells show fluorescent nucleoli, and binding is transient. CP yields residence times for mTTF-I-EGFP of ∼13 s. PMID:12719264

  4. Bioplastique as a complement in conventional plastic surgery.

    Science.gov (United States)

    Nácul, A M; Nácul, A P; Greca de Born, A

    1998-01-01

    This research presents reports of cases where a biocompatible and alloplastic biomaterial-Bioplastique-was used, associated with conventional plastic surgery or as a complement to it, with the aim of achieving a better final aesthetic result. Four cases are presented where Bioplastique was used in association with rhytidoplasty, rhinoplasty, and other surgical techniques. This material has shown itself to be appropriate to complement surgery; achieving a final result which would not be possible without any resort to a complement or any other hard procedure by the surgeon and is not more traumatic for the patient. PMID:9852179

  5. Structural basis for simvastatin competitive antagonism of complement receptor 3

    DEFF Research Database (Denmark)

    Jensen, Maria Risager; Bajic, Goran; Zhang, Xianwei;

    2016-01-01

    to the complement fragments iC3b and C3d, but not to intercellular adhesion molecule-1. By virtue of the I domain's wide distribution in binding kinetics to ligands, it was possible to identify ligand binding kinetics as discriminator for simvastatin antagonism. In static cellular experiments, 15......The complement system is an important part of the innate immune response to infection, but may also cause severe complications during inflammation. Small molecule antagonists to complement receptor (CR)3 have been widely sought, but a structural basis for their mode of action is not available. We...

  6. Non-innocent electrolyte effects on bimolecular pseudo-self-exchange reactions of ruthenium ammine complexes: Evidence for electron-transfer catalysis in H-bonded ternary assemblies

    International Nuclear Information System (INIS)

    The kinetics of bimolecular pseudo-self-exchange reactions such as that between pentaammine(pyridine)ruthenium(II) and pentaammine(3-fluoropyridine)ruthenium(III) shown below,(NH3)5RuII(py)2++(NH3)5RuIII(3-Fpy)3+-bar kex(NH3)5RuIII(py)3++(NH3)5RuII(3-Fpy)2+reveal a novel form of non-covalently mediated electron transfer over distance when salts of non-innocent electrolytes such as the conjugated dicarboxylic acid anions trans,trans-muconate2- or terephthalate2- are added to the solution. The kinetic accelerations are distinct from those seen with simple electrolytes such as KCl or CaCl2, and are thus outside the realm of classical electrolyte effects described by the Debye-Huckel theory of ion atmospheres. Kinetic simulations are presented, and the rate acceleration is interpreted in the context of possible superexchange-type interactions taking place in hydrogen-bonded ternary (or higher) association complexes which create new kinetic pathways for electron transfer over distance in aqueous solution

  7. Reviews in fluorescence 2010

    CERN Document Server

    Geddes, Chris D

    2011-01-01

    ""Reviews in Fluorescence 2010"", the seventh volume of the book serial from Springer, serves as a comprehensive collection of current trends and emerging hot topics in the field of fluorescence and closely related disciplines. It summarizes the year's progress in fluorescence and its applications, with authoritative analytical reviews specialized enough to be attractive to professional researchers, yet also appealing to the wider audience of scientists in related disciplines of fluorescence. ""Reviews in Fluorescence"" offers an essential reference material for any lab working in the fluoresc

  8. The role of complement in the acquired immune response

    DEFF Research Database (Denmark)

    Nielsen, C H; Fischer, E M; Leslie, R G

    2000-01-01

    specific T cells; the activation of a CD21/CD19 complex-mediated signalling pathway in B cells, which provides a stimulus synergistic to that induced by antigen interaction with the B-cell receptor (BCR); and promotion of the interaction between B cells and FDC, where C3d-bearing immune complexes......Studies over the past three decades have clearly established a central role for complement in the promotion of a humoral immune response. The primary function of complement, in this regard, is to opsonize antigen or immune complexes for uptake by complement receptor type 2 (CR2, CD21) expressed on...... B cells, follicular dendritic cells (FDC) and some T cells. A variety of mechanisms appear to be involved in complement-mediated promotion of the humoral response. These include: enhancement of antigen (Ag) uptake and processing by both Ag-specific and non-specific B cells for presentation to...

  9. Truly quantitative analysis of the firefly luciferase complementation assay

    Directory of Open Access Journals (Sweden)

    Renee Dale

    2016-04-01

    Full Text Available Luciferase complementation assays detect protein-protein interactions within living cells using bioluminescence. Since the first report using plant cells was published in 2007, over 100 peer-reviewed articles have been published describing the detection of protein-protein interactions within plant cells by the assays. The assays have also been used to analyze networks of protein-protein interactions in plants. Although the assays have a high dynamic range, they remain qualitative with respect to determining the affinities of interactions. In this article, we first summarize the luciferase complementation assays developed in the past years. We then describe the mechanism of the firefly luciferase complementation that is most widely used in plants, and the reason it is qualitative rather than quantitative using a mathematical model. Finally, we discuss possible procedures to quantitatively determine the affinity of a protein pair using the firefly luciferase complementation assay.

  10. Protective responses to sublytic complement in the retinal pigment epithelium.

    Science.gov (United States)

    Tan, Li Xuan; Toops, Kimberly A; Lakkaraju, Aparna

    2016-08-01

    The retinal pigment epithelium (RPE) is a key site of injury in inherited and age-related macular degenerations. Abnormal activation of the complement system is a feature of these blinding diseases, yet how the RPE combats complement attack is poorly understood. The complement cascade terminates in the cell-surface assembly of membrane attack complexes (MACs), which promote inflammation by causing aberrant signal transduction. Here, we investigated mechanisms crucial for limiting MAC assembly and preserving cellular integrity in the RPE and asked how these are compromised in models of macular degeneration. Using polarized primary RPE and the pigmented Abca4(-/-) Stargardt disease mouse model, we provide evidence for two protective responses occurring within minutes of complement attack, which are essential for maintaining mitochondrial health in the RPE. First, accelerated recycling of the membrane-bound complement regulator CD59 to the RPE cell surface inhibits MAC formation. Second, fusion of lysosomes with the RPE plasma membrane immediately after complement attack limits sustained elevations in intracellular calcium and prevents mitochondrial injury. Cholesterol accumulation in the RPE, induced by vitamin A dimers or oxidized LDL, inhibits these defense mechanisms by activating acid sphingomyelinase (ASMase), which increases tubulin acetylation and derails organelle traffic. Defective CD59 recycling and lysosome exocytosis after complement attack lead to mitochondrial fragmentation and oxidative stress in the RPE. Drugs that stimulate cholesterol efflux or inhibit ASMase restore both these critical safeguards in the RPE and avert complement-induced mitochondrial injury in vitro and in Abca4(-/-) mice, indicating that they could be effective therapeutic approaches for macular degenerations. PMID:27432952

  11. Interaction of campylobacter species with antibody, complement and phagocytes.

    OpenAIRE

    Bernatowska, E.; Jose, P; Davies, H; Stephenson, M.; Webster, D

    1989-01-01

    The opsonisation of four different campylobacter species for human neutrophils was studied using a chemiluminescence system and electron microscopy. Opsonisation of Campylobacter fetus, Campylobacter coli, and Campylobacter jejuni was mediated by antibody and enhanced by complement. Antibody was not, however, required for the phagocytosis of Campylobacter pylori because it activates the classical pathway of complement directly. This unusual property may be important in the pathogenesis of C p...

  12. Cercarial glycocalyx of Schistosoma mansoni activates human complement.

    OpenAIRE

    Samuelson, J C; Caulfield, J. P.

    1986-01-01

    Human complement activation by cercariae and schistosomula of the human parasite Schistosoma mansoni was studied in vitro. Cercariae are composed of tails which are shed after infection of the host and bodies which transform into the larvae or schistosomula after infection. After incubation in fresh normal human serum (NHS), cercarial tails bound more anti-C3 antibodies than did cercarial bodies (CB), and the tails were rapidly lysed, while the attached CB remained intact. Complement activati...

  13. Complementation in the Group of Units of Matrix Rings

    CERN Document Server

    Wilcox, Stewart

    2010-01-01

    Let $R$ be a ring with $1$ and $\\J(R)$ its Jacobson radical. Then $1+\\J(R)$ is a normal subgroup of the group of units, $G(R)$. The existence of a complement to this subgroup was explored in a paper by Coleman and Easdown; in particular the ring $R=\\Mat_n(\\Z_{p^k})$ was considered. We prove the remaining cases to determine for which $n$, $p$ and $k$ a complement exists in this ring.

  14. The problems of the complex sentences with complements in Bulgarian

    OpenAIRE

    Nicolova Ruselina

    2008-01-01

    The investigation of the complex sentences with complements in Bulgarian is a multifactor analysis, which has to take into account the following issues: a) the lexical meaning of the main predicate, which determines the meaning of the complement in general; b) the grammatical meanings of the main predicate - person (a special role plays the opposition between the speaker and the other participants in communication), number, tense, mood, evidentiality affirmativity or negation; c) the function...

  15. The Role of Complement System in Septic Shock

    Directory of Open Access Journals (Sweden)

    Jean Charchaflieh

    2012-01-01

    Full Text Available Septic shock is a critical clinical condition with a high mortality rate. A better understanding of the underlying mechanisms is important to develop effective therapies. Basic and clinical studies suggest that activation of complements in the common cascade, for example, complement component 3 (C3 and C5, is involved in the development of septic shock. The involvement of three upstream complement pathways in septic shock is more complicated. Both the classical and alternative pathways appear to be activated in septic shock, but the alternative pathway may be activated earlier than the classical pathway. Activation of these two pathways is essential to clear endotoxin. Recent investigations have shed light on the role of lectin complement pathway in septic shock. Published reports suggest a protective role of mannose-binding lectin (MBL against sepsis. Our preliminary study of MBL-associated serine protease-2 (MASP-2 in septic shock patients indicated that acute decrease of MASP-2 in the early phase of septic shock might correlate with in-hospital mortality. It is unknown whether excessive activation of these three upstream complement pathways may contribute to the detrimental effects in septic shock. This paper also discusses additional complement-related pathogenic mechanisms and intervention strategies for septic shock.

  16. Fluorescence quenching of 7-amino-4-methylcoumarin by different TEMPO derivatives

    Science.gov (United States)

    Żamojć, Krzysztof; Wiczk, Wiesław; Zaborowski, Bartłomiej; Jacewicz, Dagmara; Chmurzyński, Lech

    2015-02-01

    The fluorescence quenching of 7-amino-4-methylcoumarin by different TEMPO derivatives was studied in aqueous solutions with the use of steady-state, time-resolved fluorescence spectroscopy as well as UV-VIS absorption spectroscopy methods. In order to distinguish each TEMPO derivative from the others and to understand the mechanism of quenching, the absorption and fluorescence emission spectra as well as decays of the fluorescence of 7-amino-4-methylcoumarin were registered as a function of each TEMPO derivative concentration. There were no deviations from a linearity in the Stern-Volmer plots (determined from both, steady-state and time-resolved measurements). The fluorescence quenching mechanism was found to be entirely collisional, what was additionally confirmed by the registration of Stern-Volmer plots at 5 temperatures ranging from 15 to 55 °C. Based on theoretical calculations of molecular radii and ionization potentials of all TEMPO derivatives the mechanism of electron transfer was rejected. The fluorescence quenching which was being studied seems to be diffusion-limited and caused by the increase of non-radiative processes, such as an internal conversion and an intersystem crossing. The Stern-Volmer quenching constants and bimolecular quenching constants were determined at the room temperature for all TEMPO derivatives studied. Among all TEMPO derivatives studied TEMPO-4-amino-4-carboxylic acid (TOAC) was found to be the most effective quencher of 7-amino-4-methylcoumarin fluorescence (kq for TOAC was approximately 1.5 higher than kq for other TEMPO compounds studied). The findings demonstrate the possibility of developing an analytical method for the quantitative determination of TOAC, which incorporation into membrane proteins may provide a direct detection of peptide backbone dynamics.

  17. Fluorescent optical position sensor

    Science.gov (United States)

    Weiss, Jonathan D.

    2005-11-15

    A fluorescent optical position sensor and method of operation. A small excitation source side-pumps a localized region of fluorescence at an unknown position along a fluorescent waveguide. As the fluorescent light travels down the waveguide, the intensity of fluorescent light decreases due to absorption. By measuring with one (or two) photodetectors the attenuated intensity of fluorescent light emitted from one (or both) ends of the waveguide, the position of the excitation source relative to the waveguide can be determined by comparing the measured light intensity to a calibrated response curve or mathematical model. Alternatively, excitation light can be pumped into an end of the waveguide, which generates an exponentially-decaying continuous source of fluorescent light along the length of the waveguide. The position of a photodetector oriented to view the side of the waveguide can be uniquely determined by measuring the intensity of the fluorescent light emitted radially at that location.

  18. Fluorescence correlation spectroscopy

    NARCIS (Netherlands)

    M.A. Hink

    2015-01-01

    Fluorescence fluctuation spectroscopy techniques allow the quantification of fluorescent molecules present at the nanomolar concentration level. After a brief introduction to the technique, this chapter presents a protocol including background information in order to measure and quantify the molecul

  19. Antibodies That Efficiently Form Hexamers upon Antigen Binding Can Induce Complement-Dependent Cytotoxicity under Complement-Limiting Conditions

    Science.gov (United States)

    Cook, Erika M.; Lindorfer, Margaret A.; van der Horst, Hilma; Oostindie, Simone; Beurskens, Frank J.; Schuurman, Janine; Zent, Clive S.; Burack, Richard; Parren, Paul W. H. I.

    2016-01-01

    Recently, we demonstrated that IgG Abs can organize into ordered hexamers after binding their cognate Ags expressed on cell surfaces. This process is dependent on Fc:Fc interactions, which promote C1q binding, the first step in classical pathway complement activation. We went on to engineer point mutations that stimulated IgG hexamer formation and complement-dependent cytotoxicity (CDC). The hexamer formation–enhanced (HexaBody) CD20 and CD38 mAbs support faster, more robust CDC than their wild-type counterparts. To further investigate the CDC potential of these mAbs, we used flow cytometry, high-resolution digital imaging, and four-color confocal microscopy to examine their activity against B cell lines and primary chronic lymphocytic leukemia cells in sera depleted of single complement components. We also examined the CDC activity of alemtuzumab (anti-CD52) and mAb W6/32 (anti-HLA), which bind at high density to cells and promote substantial complement activation. Although we observed little CDC for mAb-opsonized cells reacted with sera depleted of early complement components, we were surprised to discover that the Hexabody mAbs, as well as ALM and W6/32, were all quite effective at promoting CDC in sera depleted of individual complement components C6 to C9. However, neutralization studies conducted with an anti-C9 mAb verified that C9 is required for CDC activity against cell lines. These highly effective complement-activating mAbs efficiently focus activated complement components on the cell, including C3b and C9, and promote CDC with a very low threshold of MAC binding, thus providing additional insight into their enhanced efficacy in promoting CDC. PMID:27474078

  20. Protein subcellular localization assays using split fluorescent proteins

    Science.gov (United States)

    Waldo, Geoffrey S.; Cabantous, Stephanie

    2009-09-08

    The invention provides protein subcellular localization assays using split fluorescent protein systems. The assays are conducted in living cells, do not require fixation and washing steps inherent in existing immunostaining and related techniques, and permit rapid, non-invasive, direct visualization of protein localization in living cells. The split fluorescent protein systems used in the practice of the invention generally comprise two or more self-complementing fragments of a fluorescent protein, such as GFP, wherein one or more of the fragments correspond to one or more beta-strand microdomains and are used to "tag" proteins of interest, and a complementary "assay" fragment of the fluorescent protein. Either or both of the fragments may be functionalized with a subcellular targeting sequence enabling it to be expressed in or directed to a particular subcellular compartment (i.e., the nucleus).

  1. Diversity and evolution of coral fluorescent proteins.

    Directory of Open Access Journals (Sweden)

    Naila O Alieva

    Full Text Available GFP-like fluorescent proteins (FPs are the key color determinants in reef-building corals (class Anthozoa, order Scleractinia and are of considerable interest as potential genetically encoded fluorescent labels. Here we report 40 additional members of the GFP family from corals. There are three major paralogous lineages of coral FPs. One of them is retained in all sampled coral families and is responsible for the non-fluorescent purple-blue color, while each of the other two evolved a full complement of typical coral fluorescent colors (cyan, green, and red and underwent sorting between coral groups. Among the newly cloned proteins are a "chromo-red" color type from Echinopora forskaliana (family Faviidae and pink chromoprotein from Stylophora pistillata (Pocilloporidae, both evolving independently from the rest of coral chromoproteins. There are several cyan FPs that possess a novel kind of excitation spectrum indicating a neutral chromophore ground state, for which the residue E167 is responsible (numeration according to GFP from A. victoria. The chromoprotein from Acropora millepora is an unusual blue instead of purple, which is due to two mutations: S64C and S183T. We applied a novel probabilistic sampling approach to recreate the common ancestor of all coral FPs as well as the more derived common ancestor of three main fluorescent colors of the Faviina suborder. Both proteins were green such as found elsewhere outside class Anthozoa. Interestingly, a substantial fraction of the all-coral ancestral protein had a chromohore apparently locked in a non-fluorescent neutral state, which may reflect the transitional stage that enabled rapid color diversification early in the history of coral FPs. Our results highlight the extent of convergent or parallel evolution of the color diversity in corals, provide the foundation for experimental studies of evolutionary processes that led to color diversification, and enable a comparative analysis of

  2. Fluorescence quenching of CdS quantum dots by 4-azetidinyl-7-nitrobenz-2-oxa-1,3-diazole: a mechanistic study.

    Science.gov (United States)

    Santhosh, Kotni; Patra, Satyajit; Soumya, S; Khara, Dinesh Chandra; Samanta, Anunay

    2011-10-24

    Fluorescence quenching of CdS quantum dots (QDs) by 4-azetidinyl-7-nitrobenz-2-oxa-1,3-diazole (NBD), where the two quenching partners satisfy the spectral overlap criterion necessary for Förster resonance energy transfer (FRET), is studied by steady-state and time-resolved fluorescence techniques. The fluorescence quenching of the QDs is accompanied by an enhancement of the acceptor fluorescence and a reduction of the average fluorescence lifetime of the donor. Even though these observations are suggestive of a dynamic energy transfer process, it is shown that the quenching actually proceeds through a static interaction between the quenching partners and is probably mediated by charge-transfer interactions. The bimolecular quenching rate constant estimated from the Stern-Volmer plot of the fluorescence intensities, is found to be exceptionally high and unrealistic for the dynamic quenching process. Hence, a kinetic model is employed for the estimation of actual quencher/QD ratio dependent exciton quenching rate constants of the fluorescence quenching of CdS by NBD. The present results point to the need for a deeper analysis of the experimental quenching data to avoid erroneous conclusions. PMID:22002891

  3. The coherent dynamics of photoexcited green fluorescent proteins

    CERN Document Server

    Cinelli, R A G; Pellegrini, V; Beltram, F; Cerullo, G; Zavelani-Rossi, M; De Silvestri, S; Tyagi, M; Giacca, M; Cinelli, Riccardo A. G.; Tozzini, Valentina; Pellegrini, Vittorio; Beltram, Fabio; Cerullo, Giulio; Zavelani-Rossi, Margherita; Silvestri, Sandro De; Tyagi, Mudit; Giacca, Mauro

    2001-01-01

    The coherent dynamics of vibronic wave packets in the green fluorescent protein is reported. At room temperature the non-stationary dynamics following impulsive photoexcitation displays an oscillating optical transmissivity pattern with components at 67 fs (497 cm-1) and 59 fs (593 cm-1). Our results are complemented by ab initio calculations of the vibrational spectrum of the chromophore. This analysis shows the interplay between the dynamics of the aminoacidic structure and the electronic excitation in the primary optical events of green fluorescent proteins.

  4. Versatile protein tagging in cells with split fluorescent protein

    OpenAIRE

    Kamiyama, Daichi; Sekine, Sayaka; Barsi-Rhyne, Benjamin; Hu, Jeffrey; Chen, Baohui; Gilbert, Luke A.; Ishikawa, Hiroaki; Leonetti, Manuel D.; Marshall, Wallace F.; Jonathan S Weissman; Huang, Bo

    2016-01-01

    In addition to the popular method of fluorescent protein fusion, live cell protein imaging has now seen more and more application of epitope tags. The small size of these tags may reduce functional perturbation and enable signal amplification. To address their background issue, we adapt self-complementing split fluorescent proteins as epitope tags for live cell protein labelling. The two tags, GFP11 and sfCherry11 are derived from the eleventh β-strand of super-folder GFP and sfCherry, respec...

  5. Micrurus snake venoms activate human complement system and generate anaphylatoxins

    Directory of Open Access Journals (Sweden)

    Tanaka Gabriela D

    2012-01-01

    Full Text Available Abstract Background The genus Micrurus, coral snakes (Serpentes, Elapidae, comprises more than 120 species and subspecies distributed from the south United States to the south of South America. Micrurus snake bites can cause death by muscle paralysis and further respiratory arrest within a few hours after envenomation. Clinical observations show mainly neurotoxic symptoms, although other biological activities have also been experimentally observed, including cardiotoxicity, hemolysis, edema and myotoxicity. Results In the present study we have investigated the action of venoms from seven species of snakes from the genus Micrurus on the complement system in in vitro studies. Several of the Micrurus species could consume the classical and/or the lectin pathways, but not the alternative pathway, and C3a, C4a and C5a were generated in sera treated with the venoms as result of this complement activation. Micrurus venoms were also able to directly cleave the α chain of the component C3, but not of the C4, which was inhibited by 1,10 Phenanthroline, suggesting the presence of a C3α chain specific metalloprotease in Micrurus spp venoms. Furthermore, complement activation was in part associated with the cleavage of C1-Inhibitor by protease(s present in the venoms, which disrupts complement activation control. Conclusion Micrurus venoms can activate the complement system, generating a significant amount of anaphylatoxins, which may assist due to their vasodilatory effects, to enhance the spreading of other venom components during the envenomation process.

  6. LPS induces pulp progenitor cell recruitment via complement activation.

    Science.gov (United States)

    Chmilewsky, F; Jeanneau, C; Laurent, P; About, I

    2015-01-01

    Complement system, a major component of the natural immunity, has been recently identified as an important mediator of the dentin-pulp regeneration process through STRO-1 pulp cell recruitment by the C5a active fragment. Moreover, it has been shown recently that under stimulation with lipoteichoic acid, a complex component of the Gram-positive bacteria cell wall, human pulp fibroblasts are able to synthesize all proteins required for complement activation. However, Gram-negative bacteria, which are also involved in tooth decay, are known as powerful activators of complement system and inflammation. Here, we investigated the role of Gram-negative bacteria-induced complement activation on the pulp progenitor cell recruitment using lipopolysaccharide (LPS), a major component of all Gram-negative bacteria. Our results show that incubating pulp fibroblasts with LPS induced membrane attack complex formation and C5a release in serum-free fibroblast cultures. The produced C5a binds to the pulp progenitor cells' membrane and induces their migration toward the LPS stimulation chamber, as revealed by the dynamic transwell migration assays. The inhibition of this migration by the C5aR-specific antagonist W54011 indicates that the pulp progenitor migration is mediated by the interaction between C5a and C5aR. Our findings demonstrate, for the first time, a direct interaction between the recruitment of progenitor pulp cells and the activation of complement system generated by pulp fibroblast stimulation with LPS. PMID:25359783

  7. Investigating Lyophilization of Lipid Nanocapsules with Fluorescence Correlation Spectroscopy

    OpenAIRE

    Smith, Polina B.; Dendramis, Kimberly A.; Chiu, Daniel T.

    2010-01-01

    This paper describes characterization of lyophilized lipid nanocapsules loaded with Alexa 488 by fluorescence correlation spectroscopy (FCS). Fluorimetry analysis of nanocapsules containing self-quenching concentrations of 5-(and-6)-carboxyfluorescein was performed to establish a point of reference for FCS. FCS results complemented the results obtained by fluorimetry for a bulk nanocapsule solution and provided additional information about the size and dye retention by individual nanocapsules...

  8. Screening a cDNA library for protein-protein interactions directly in planta

    Czech Academy of Sciences Publication Activity Database

    Lee, L.-Y.; Wu, F.-H.; Hsu, Ch.-T.; Shen, S.-Ch.; Yeh, H.-Y.; Liao, D.-Ch.; Fang, M.-J.; Liu, N.-T.; Yen, Y.-Ch.; Dokládal, Ladislav; Sýkorová, Eva; Gelvin, S.B.; Lin, Ch.-S.

    2012-01-01

    Roč. 24, č. 5 (2012), s. 1746-1759. ISSN 1040-4651 R&D Projects: GA AV ČR(CZ) IAA500040801 Institutional research plan: CEZ:AV0Z50040702 Keywords : bimolecular fluorescence complementation * telomerase-binding-protein * transformation Subject RIV: BO - Biophysics Impact factor: 9.251, year: 2012

  9. Functional analysis of Ficolin-3 mediated complement activation

    DEFF Research Database (Denmark)

    Hein, Estrid; Honoré, Christian; Skjoedt, Mikkel-Ole;

    2010-01-01

    assessed by C4, C3 and terminal complement complex (TCC) deposition. Serum Ficolin-3 bound to acBSA in a calcium dependent manner, while only minimal binding of Ficolin-2 and no binding of Ficolin-1 were observed. No binding to normal BSA was seen for any of the Ficolins. Serum C4, C3 and TCC deposition on...... acBSA were dependent only on Ficolin-3 in appropriate serum dilutions. Deposition of down stream complement components correlated highly significantly with the serum concentration of Ficolin-3 but not with Ficolin-2 in healthy donors. To make the assay robust for clinical use a chemical compound was...... possibility to diagnose functional and genetic defects of Ficolin-3 and down stream components in the lectin complement pathway....

  10. How regional non-proliferation arrangements complement international verification

    International Nuclear Information System (INIS)

    This presentation focuses on international verification in the form of IAEA Safeguards, and discusses the relationship between IAEA safeguards and the relevant regional arrangements, both the existing and the future. For most States the political commitment against acquisition of nuclear weapons has been carefully reached and strongly held. Their observance of treaty commitments does not depend on the deterrent effect of verification activities. Safeguards serve to assist States who recognise it is in their own interest to demonstrate their compliance to others. Thus safeguards are a vital confidence building measure in their own right, as well as being a major complement to the broader range of international confidence building measures. Safeguards can both complement other confidence building measures and in turn be complemented by them. Within consideration of how it could work it is useful to consider briefly current developments of IAEA safeguards, i.e. existing regional arrangements and nuclear weapon free zones

  11. Lessons learned from mice deficient in lectin complement pathway molecules

    DEFF Research Database (Denmark)

    Genster, Ninette; Takahashi, Minoru; Sekine, Hideharu;

    2014-01-01

    differences in the genetic arrangements of murine and human orthologues of lectin pathway molecules, the knockout mice have proven to be valuable models to explore the effect of deficiency states in humans. In addition, new insight and unexpected findings on the diverse roles of lectin pathway molecules in......The lectin pathway of the complement system is initiated when the pattern-recognition molecules, mannose-binding lectin (MBL), ficolins or collectin-11, bind to invading pathogens or damaged host cells. This leads to activation of MBL/ficolin/collectin-11 associated serine proteases (MASPs), which...... in turn activate downstream complement components, ultimately leading to elimination of the pathogen. Mice deficient in the key molecules of lectin pathway of complement have been generated in order to build knowledge of the molecular mechanisms of the lectin pathway in health and disease. Despite...

  12. Progress in Parallel Schur Complement Preconditioning for Computational Fluid Dynamics

    Science.gov (United States)

    Barth, Timothy J.; Chan, Tony F.; Tang, Wei-Pai; Chancellor, Marisa K. (Technical Monitor)

    1997-01-01

    We consider preconditioning methods for nonself-adjoint advective-diffusive systems based on a non-overlapping Schur complement procedure for arbitrary triangulated domains. The ultimate goal of this research is to develop scalable preconditioning algorithms for fluid flow discretizations on parallel computing architectures. In our implementation of the Schur complement preconditioning technique, the triangulation is first partitioned into a number of subdomains using the METIS multi-level k-way partitioning code. This partitioning induces a natural 2X2 partitioning of the p.d.e. discretization matrix. By considering various inverse approximations of the 2X2 system, we have developed a family of robust preconditioning techniques. A computer code based on these ideas has been developed and tested on the IBM SP2 and the SGI Power Challenge array using MPI message passing protocol. A number of example CFD calculations will be presented to illustrate and assess various Schur complement approximations.

  13. The Least Eigenvalue of Graphs whose Complements Are Uni- cyclic

    Directory of Open Access Journals (Sweden)

    Wang Yi

    2015-05-01

    Full Text Available A graph in a certain graph class is called minimizing if the least eigenvalue of its adjacency matrix attains the minimum among all graphs in that class. Bell et al. have identified a subclass within the connected graphs of order n and size m in which minimizing graphs belong (the complements of such graphs are either disconnected or contain a clique of size n/2 . In this paper we discuss the minimizing graphs of a special class of graphs of order n whose complements are connected and contains exactly one cycle (namely the class Ucn of graphs whose complements are unicyclic, and characterize the unique minimizing graph in Ucn when n ≥ 20.

  14. Absence of functional alternative complement pathway alleviates lupus cerebritis.

    Science.gov (United States)

    Alexander, Jessy J; Jacob, Alexander; Vezina, Paul; Sekine, Hideharu; Gilkeson, Gary S; Quigg, Richard J

    2007-06-01

    The complement inhibitor, Crry, which blocks both the classical and alternative pathways, alleviates CNS disease in the lupus model, MRL/MpJ-Tnfrsf6lpr (MRL/lpr) mice. To understand the role of the alternative pathway, we studied mice deficient in a key alternative pathway protein, complement factor B (fB). Immune deposits (IgG and C3) were reduced in the brains of MRL/lpr fB-deficient (fB-/-MRL/lpr) compared to fB-sufficient (MRL/lpr) mice, indicating reduced complement activation. Reduced neutrophil infiltration (22% of MRL/lpr mice) and apoptosis (caspase-3 activity was reduced to 33% of MRL/lpr mice) in these mice indicates that the absence of the alternative pathway was neuroprotective. Furthermore, expression of phospho (p)-Akt (0.16+/-0.02 vs. 0.35+/-0.13, pcerebritis. PMID:17523212

  15. Interaction of antihypertensive drug amiloride with metal ions in micellar medium using fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gujar, Varsha; Pundge, Vijaykumar; Ottoor, Divya, E-mail: divya@chem.unipune.ac.in

    2015-05-15

    Steady state and life time fluorescence spectroscopy have been employed to study the interaction of antihypertensive drug amiloride with biologically important metal ions i.e. Cu{sup 2+}, Fe{sup 2+}, Ni{sup 2+} and Zn{sup 2+} in various micellar media (anionic SDS (sodium dodecyl sulfate), nonionic TX-100 (triton X-100) and cationic CTAB (cetyl trimethyl ammonium bromide)). It was observed that fluorescence properties of drug remain unaltered in the absence of micellar media with increasing concentration of metal ions. However, addition of Cu{sup 2+}, Fe{sup 2+} and Ni{sup 2+} caused fluorescence quenching of amiloride in the presence of anionic micelle, SDS. Binding of drug with metal ions at the charged micellar interface could be the possible reason for this pH-dependent metal-mediated fluorescence quenching. There were no remarkable changes observed due to metal ions addition when drug was present in cationic and nonionic micellar medium. The binding constant and bimolecular quenching constant were evaluated and compared for the drug–metal complexes using Stern–Volmer equation and fluorescence lifetime values. - Highlights: • Interaction of amiloride with biologically important metal ions, Fe{sup 2+}, Cu{sup 2+}, Ni{sup 2+} and Zn{sup 2+}. • Monitoring the interaction in various micelle at different pH by fluorescence spectroscopy. • Micelles acts as receptor, amiloride as transducer and metal ions as analyte in the present system. • Interaction study provides pH dependent quenching and binding mechanism of drug with metal ions.

  16. The complement C3 protein family in invertebrates

    Directory of Open Access Journals (Sweden)

    M Nonaka

    2011-01-01

    Full Text Available Complement C3 plays a pivotal role in the innate immune system of mammals as the central component of the complement system essential for its activation mechanism and effecter function. C3 has a unique intra-chain thioester bond that is shared by some complement and non-complement proteins forming a thioester protein (TEP family. Phylogenetic analysis of TEP family genes of vertebrates and invertebrates revealed that the TEP family is divided into two subfamilies, the C3 subfamily and the alpha-2-macroglobulin (A2M subfamily. The establishment of the TEP genes and differentiation of them into the C3 and A2M subfamilies occurred prior to the divergence of Cnidaria and Bilateria, in a common ancestor of Eumetazoa more than 600 MYA. Since then the A2M subfamily has been retained by all metazoan lineages analyzed thus far. In contrast, the C3 subfamily has been retained only by deuterostomes and some protostomes, and has been lost in multiple protostome lineages. Although the direct functional analysis of the most invertebrate TEPs is still to be performed, conservation of the basic domain structure and functionally important residues for each molecule suggests that the basic function is also conserved. Functional analyses performed on a few invertebrate C3 support this conclusion. The gene duplication events that generated C4 and C5 from C3 occurred in a common ancestor of jawed vertebrates, indicating that invertebrate and cyclostome C3s represent the pre-duplication state. In addition to C3, complement Bf and MASP involved in the activation of C3 are also identified in Cnidaria and some invertebrates, indicating that the complement system is one of the most ancient innate immune systems of Eumetazoa.

  17. Complement activation in Ghanaian children with severe Plasmodium falciparum malaria

    Directory of Open Access Journals (Sweden)

    Ofori Michael F

    2007-12-01

    Full Text Available Abstract Background Severe anaemia (SA, intravascular haemolysis (IVH and respiratory distress (RD are severe forms of Plasmodium falciparum malaria, with RD reported to be of prognostic importance in African children with malarial anaemia. Complement factors have been implicated in the mechanism leading to excess anaemia in acute P. falciparum infection. Methods The direct Coombs test (DCT and flow cytometry were used to investigate the mean levels of RBC-bound complement fragments (C3d and C3bαβ and the regulatory proteins [complement receptor 1 (CD35 and decay accelerating factor (CD55] in children with discrete clinical forms of P. falciparum malaria. The relationship between the findings and clinical parameters including coma, haemoglobin (Hb levels and RD were investigated. Results Of the 484 samples tested, 131(27% were positive in DCT, out of which 115/131 (87.8% were positive for C3d alone while 16/131 (12.2% were positive for either IgG alone or both. 67.4% of the study population were below 5 years of age and DCT positivity was more common in this age group relative to children who were 5 years or older (Odds ratio, OR = 3.8; 95%CI, 2.2–6.7, p Conclusion These results suggest that complement activation contributed to anaemia in acute childhood P. falciparum malaria, possibly through induction of erythrophagocytosis and haemolysis. In contrast to other studies, this study did not find association between levels of the complement regulatory proteins, CD35 and CD55 and malarial anaemia. These findings suggest that complement activation could also be involved in the pathogenesis of RD but larger studies are needed to confirm this finding.

  18. Microbes bind complement inhibitor factor H via a common site.

    Science.gov (United States)

    Meri, T; Amdahl, H; Lehtinen, M J; Hyvärinen, S; McDowell, J V; Bhattacharjee, A; Meri, S; Marconi, R; Goldman, A; Jokiranta, T S

    2013-01-01

    To cause infections microbes need to evade host defense systems, one of these being the evolutionarily old and important arm of innate immunity, the alternative pathway of complement. It can attack all kinds of targets and is tightly controlled in plasma and on host cells by plasma complement regulator factor H (FH). FH binds simultaneously to host cell surface structures such as heparin or glycosaminoglycans via domain 20 and to the main complement opsonin C3b via domain 19. Many pathogenic microbes protect themselves from complement by recruiting host FH. We analyzed how and why different microbes bind FH via domains 19-20 (FH19-20). We used a selection of FH19-20 point mutants to reveal the binding sites of several microbial proteins and whole microbes (Haemophilus influenzae, Bordetella pertussis, Pseudomonas aeruginosa, Streptococcus pneumonia, Candida albicans, Borrelia burgdorferi, and Borrelia hermsii). We show that all studied microbes use the same binding region located on one side of domain 20. Binding of FH to the microbial proteins was inhibited with heparin showing that the common microbial binding site overlaps with the heparin site needed for efficient binding of FH to host cells. Surprisingly, the microbial proteins enhanced binding of FH19-20 to C3b and down-regulation of complement activation. We show that this is caused by formation of a tripartite complex between the microbial protein, FH, and C3b. In this study we reveal that seven microbes representing different phyla utilize a common binding site on the domain 20 of FH for complement evasion. Binding via this site not only mimics the glycosaminoglycans of the host cells, but also enhances function of FH on the microbial surfaces via the novel mechanism of tripartite complex formation. This is a unique example of convergent evolution resulting in enhanced immune evasion of important pathogens via utilization of a "superevasion site." PMID:23637600

  19. Complement C3: an emerging risk factor in cardiometabolic disease

    OpenAIRE

    Hertle, E.; van Greevenbroek, M.M.J.; Stehouwer, C.D.A.

    2012-01-01

    C3 is the central component of the complement system and activation of C3 via any of the three major activation pathways—the classical, the lectin and the alternative pathways—results in initiation of the terminal complement pathway and release of the anaphylatoxin C3a. Both terminal pathway activation and signalling of C3a and its inactivation product C3a-desarg via the C3a receptor and C5a-like receptor 2, respectively, can induce inflammatory, immunomodulatory and metabolic responses. C3 h...

  20. Feedback Enhancement of Antibody Responses via Complement and Fc Receptors

    OpenAIRE

    Dahlström, Jörgen

    2001-01-01

    IgG, IgM and IgE in complex with antigen have the capacity to regulate specific immune responses. In this investigation, the role of Fc receptors for IgG (FcγRI, FcγRII and FcγRIII) and complement receptors 1 and 2 (CR1/2) for antibody-mediated enhancement of antibody responses are investigated. IgM is known to efficiently activate complement and thereby enhance specific antibody responses but it is not known if this involves binding to CR1/2. Using CR1/2 deficient mice, immunized with sheep ...

  1. Functional analysis of Ficolin-3 mediated complement activation

    DEFF Research Database (Denmark)

    Hein, Estrid; Honoré, Christian Le Fèvre; Skjoedt, Mikkel-Ole;

    2010-01-01

    assessed by C4, C3 and terminal complement complex (TCC) deposition. Serum Ficolin-3 bound to acBSA in a calcium dependent manner, while only minimal binding of Ficolin-2 and no binding of Ficolin-1 were observed. No binding to normal BSA was seen for any of the Ficolins. Serum C4, C3 and TCC deposition on...... applied to the samples that inhibited interference from the classical pathway due to the presence of anti-BSA antibodies in some sera. We describe a novel functional method for measuring complement activation mediated by Ficolin-3 in human serum up to the formation of TCC. The assay provides the...

  2. Blockade of alternative complement pathway in dense deposit disease.

    Science.gov (United States)

    Berthe-Aucejo, Aurore; Sacquépée, Mathieu; Fila, Marc; Peuchmaur, Michel; Perrier-Cornet, Emilia; Frémeaux-Bacchi, Véronique; Deschênes, Georges

    2014-01-01

    A patient aged 17 with dense deposit disease associated with complement activation, circulating C3 Nef, and Factor H mutation presented with nephrotic syndrome and hypertension. Steroid therapy, plasma exchange, and rituximab failed to improve proteinuria and hypertension despite a normalization of the circulating sC5b9 complex. Eculizumab, a monoclonal antibody directed against C5, was used to block the terminal product of the complement cascade. The dose was adapted to achieve a CH50 below 10%, but proteinuria and blood pressure were not improved after 3 months of treatment. PMID:24672732

  3. Gene for ataxia-telangiectasia complementation group D (ATDC)

    Science.gov (United States)

    Murnane, John P.; Painter, Robert B.; Kapp, Leon N.; Yu, Loh-Chung

    1995-03-07

    Disclosed herein is a new gene, an AT gene for complementation group D, the ATDC gene and fragments thereof. Nucleic acid probes for said gene are provided as well as proteins encoded by said gene, cDNA therefrom, preferably a 3 kilobase (kb) cDNA, and recombinant nucleic acid molecules for expression of said proteins. Further disclosed are methods to detect mutations in said gene, preferably methods employing the polymerase chain reaction (PCR). Also disclosed are methods to detect AT genes from other AT complementation groups.

  4. Leishmanial protein kinases phosphorylate components of the complement system.

    OpenAIRE

    Hermoso, T; Fishelson, Z; Becker, S I; Hirschberg, K.; Jaffe, C. L.

    1991-01-01

    Externally oriented protein kinases are present on the plasma membrane of the human parasite, Leishmania. Since activation of complement plays an important role in the survival of these parasites, we examined the ability of protein kinases from Leishmania major to phosphorylate components of the human complement system. The leishmanial protein kinase-1 (LPK-1) isolated from promastigotes of L. major was able to phosphorylate purified human C3, C5 and C9. Only the alpha-chain of C3 and C5 was ...

  5. Genetic, molecular and functional analyses of complement factor I deficiency

    DEFF Research Database (Denmark)

    Nilsson, S.C.; Trouw, L.A.; Renault, N.;

    2009-01-01

    analyze expression and secretion. The G170V mutation resulted in a protein that was not expressed, whereas the mutations Q232K, C237Y, S250L, I339M and H400L affected secretion. Furthermore, the C237Y and the S250L mutants did not degrade C4b and C3b as efficiently as the WT. The truncated Q336x mutant......Complete deficiency of complement inhibitor factor I (FI) results in secondary complement deficiency due to uncontrolled spontaneous alternative pathway activation leading to susceptibility to infections. Current genetic examination of two patients with near complete FI deficiency and three...

  6. Blockade of Alternative Complement Pathway in Dense Deposit Disease

    Directory of Open Access Journals (Sweden)

    Aurore Berthe-Aucejo

    2014-01-01

    Full Text Available A patient aged 17 with dense deposit disease associated with complement activation, circulating C3 Nef, and Factor H mutation presented with nephrotic syndrome and hypertension. Steroid therapy, plasma exchange, and rituximab failed to improve proteinuria and hypertension despite a normalization of the circulating sC5b9 complex. Eculizumab, a monoclonal antibody directed against C5, was used to block the terminal product of the complement cascade. The dose was adapted to achieve a CH50 below 10%, but proteinuria and blood pressure were not improved after 3 months of treatment.

  7. Solvent effect on the relative quantum yield and fluorescence quenching of a newly synthesized coumarin derivative.

    Science.gov (United States)

    Nagaraja, D; Melavanki, R M; Patil, N R; Geethanjali, H S; Kusanur, R A

    2015-08-01

    We estimated the relative florescence quantum yield (Φ) of 8-methoxy-3-[1-(4,5-dicarbomethoxy-1,2,3-triazoloacetyl)]coumarin [8MDTC] using a single-point method with quinine sulfate in 0.1 M of sulfuric acid used as a standard reference. The fluorescence lifetimes, radiative and non-radiative decay rate constants are calculated. Relative quantum yields were found to be less in the non-polar solvents, indicating that the solute exhibits less fluorescence in a non-polar environment. The fluorescence quenching of [8MDTC] by aniline was studied at room temperature by examining the steady state in five different solvents in order to explore various possible quenching mechanisms. The experimental results show a positive deviation in Stern-Volmer plots in all solvents. Ground state complex and sphere of action static quenching models were used to interpret the results. Many quenching rate parameters were calculated using these models. The values of these parameters suggest that the sphere of action static quenching model agrees well with the experimental results. Further, a finite sink approximation model was used to check whether these bimolecular reactions were diffusion limited or not. The values of the distance parameter R' and the diffusion coefficient D were determined and are compared with the values of the encounter distance R and diffusion coefficient D calculated using the Stokes-Einstein equation. PMID:25214175

  8. Stochastic Micro-Pattern for Automated Correlative Fluorescence - Scanning Electron Microscopy

    OpenAIRE

    Isabell Begemann; Abhiyan Viplav; Christiane Rasch; Milos Galic

    2015-01-01

    Studies of cellular surface features gain from correlative approaches, where live cell information acquired by fluorescence light microscopy is complemented by ultrastructural information from scanning electron micrographs. Current approaches to spatially align fluorescence images with scanning electron micrographs are technically challenging and often cost or time-intensive. Relying exclusively on open-source software and equipment available in a standard lab, we have developed a method for ...

  9. Complement receptor expression and activation of the complement cascade on B lymphocytes from patients with systemic lupus erythematosus (SLE)

    DEFF Research Database (Denmark)

    Marquart, H V; Svendsen, A; Rasmussen, J M; Nielsen, C H; Junker, P; Svehag, S E; Leslie, R G

    1995-01-01

    It has previously been reported that the expression of the complement receptors, CR1 on erythrocytes and blood leucocytes and CR2 on B cells, is reduced in patients with SLE, and that the reduced expression of CR1 on erythrocytes is related to disease activity. We have earlier demonstrated that...... normal B cells are capable of activating the alternative pathway (AP) of complement in a CR2-dependent fashion. In this study we have investigated whether disturbances in this activity may be related to the altered phenotype of SLE B cells. Flow cytometry was used to measure expression of complement...... receptors and regulatory proteins on B cells from SLE patients, as well as the deposition of C3 fragments occurring in vivo or after in vitro AP activation. We have confirmed, for a proportion of the patients studied, reduced expression of CR1 and CR2 on B cells, and shown a consistency between low CR2...

  10. Fluorescent fiber diagnostics

    Science.gov (United States)

    Toeppen, John S.

    1994-01-01

    A fluorescent fiber (13) having a doped core (16) is pumped (11) by light (18) of a relatively short wavelength to produce fluorescence at a longer wavelength that is detected by detector (24). The level of fluorescence is monitored (26) and evaluated to provide information as to the excitation of the fiber (13) or the environment thereof. In particular, the level of intensity of the detected fluorescence may be used to measure the intensity of a light beam (18) passing axially through an optical fiber system (12) (FIG. 1 ), or the intensity of a light beam (46) passing radially through a fluorescent fiber (13) (FIG. 2 ), or the level of a fluid (32) in a tank (31) (FIG. 3 ), or a scintillation event (37) in a fluorescent fiber (13) pumped to produce amplification of the scintillation event (FIG. 4 ).

  11. Title: Elucidation of Environmental Fate of Artificial Sweeteners (Aspartame, Acesulfame K and Saccharin) by Determining Bimolecular Rate Constants with Hydroxyl Radical at Various pH and Temperature Conditions and Possible Reaction By-Products

    Science.gov (United States)

    Teraji, T.; Arakaki, T.; Suzuka, T.

    2012-12-01

    Use of artificial sweeteners in beverages and food has been rapidly increasing because of their non-calorie nature. In Japan, aspartame, acesulfame K and sucralose are among the most widely used artificial sweeteners. Because the artificial sweeteners are not metabolized in human bodies, they are directly excreted into the environment without chemical transformations. We initiated a study to better understand the fate of artificial sweeteners in the marine environment. The hydroxyl radical (OH), the most potent reactive oxygen species, reacts with various compounds and determines the environmental oxidation capacity and the life-time of many compounds. The steady-state OH concentration and the reaction rate constants between the compound and OH are used to estimate the life-time of the compound. In this study, we determine the bimolecular rate constants between aspartame, acefulfame K and saccharin and OH at various pH and temperature conditions using a competition kinetics technique. We use hydrogen peroxide as a photochemical source of OH. Bimolecular rate constant we obtained so far for aspartame was (2.6±1.2)×109 M-1 s-1 at pH = 3.0 and (4.9±2.3)×109 M-1 s-1 at pH = 5.5. Little effect was seen by changing the temperatures between 15 and 40 oC. Activation energy (Ea) was calculated to be -1.0 kJ mol-1 at pH = 3.0, +8.5 kJ mol-1 at pH = 5.5, which could be regarded as zero. We will report bimolecular rate constants at different pHs and temperatures for acesulfame K and saccharin, as well. Possible reaction by-products for aspartame will be also reported. We will further discuss the fate of aspartame in the coastal environment.

  12. Fluorescent minerals, a review

    Science.gov (United States)

    Modreski, P.J.; Aumente-Modreski, R.

    1996-01-01

    Fluorescent minerals are more than just an attractive novelty, and collecting them is a speciality for thousands of individuals who appreciate their beauty, rarity, and scientific value. Fluorescent properties can be used as an aid to mineral identification, locality determination, and distinction between natural and synthetic gemstones. This article gives an overview of those aspects of fluorescence that are of most interest to collectors, hobbyists, and mineralogists. -from Authors

  13. Cohomology of hyperplane complements with group ring coefficients

    CERN Document Server

    Davis, Michael W; Leary, Ian J; Okun, Boris

    2010-01-01

    We compute the cohomology with group ring coefficients of the complement of a finite collection of affine hyperplanes in a finite dimensional complex vector space. It is nonzero in exactly one degree, namely the degree equal to the rank of the hyperplane arrangement.

  14. Juvenile Justice and a Strengths Perspective: Complement or Clash?

    Science.gov (United States)

    Clark, Michael D.

    2009-01-01

    Does the new realm of positive psychology and strength-based strategies complement or clash with the remedial discipline of social control traditionally practiced in juvenile justice programs? Many welcome the balance of positive psychology, the strengths perspective, and coping and resilience studies. Although emerging from different disciplines,…

  15. Complement profile and activation mechanisms by different LDL apheresis systems.

    Science.gov (United States)

    Hovland, Anders; Hardersen, Randolf; Nielsen, Erik Waage; Enebakk, Terje; Christiansen, Dorte; Ludviksen, Judith Krey; Mollnes, Tom Eirik; Lappegård, Knut Tore

    2012-07-01

    Extracorporeal removal of low-density lipoprotein (LDL) cholesterol by means of selective LDL apheresis is indicated in otherwise uncontrolled familial hypercholesterolemia. During blood-biomaterial interaction other constituents than the LDL particles are affected, including the complement system. We set up an ex vivo model in which human whole blood was passed through an LDL apheresis system with one of three different apheresis columns: whole blood adsorption, plasma adsorption and plasma filtration. The concentrations of complement activation products revealed distinctly different patterns of activation and adsorption by the different systems. Evaluated as the final common terminal complement complex (TCC) the whole blood system was inert, in contrast to the plasma systems, which generated substantial and equal amounts of TCC. Initial classical pathway activation was revealed equally for both plasma systems as increases in the C1rs-C1inh complex and C4d. Alternative pathway activation (Bb) was most pronounced for the plasma adsorption system. Although the anaphylatoxins (C3a and C5a) were equally generated by the two plasma separation systems, they were efficiently adsorbed to the plasma adsorption column before the "outlet", whereas they were left free in the plasma in the filtration system. Consequently, during blood-biomaterial interaction in LDL apheresis the complement system is modulated in different manners depending on the device composition. PMID:22373816

  16. Complex arrangements whose complement has Euler characteristic +/-1

    OpenAIRE

    Jacobs, Philippe; Laeremans, A.

    1997-01-01

    In this article we prove that a complex arrangement (i.e. a finite union of hyperplanes in C-n) whose complement has Euler characteristic +/-1 is defined over Q, meaning that there exist coordinates such that the equations of the hyperplanes of the arrangement have rational coefficients.

  17. The Subject Complement – a Contrastive Romanian-German Approach

    OpenAIRE

    Alina Pădurean

    2012-01-01

    The researchers have increasingly focused their attention on contrastive analysis studies, over the past few years. Therefore, in this study we aim at approaching the subject complement from a contrastive Romanian-German point of view. Our scientific approach is structured on two levels: the identification of similarities but also of differences between these two languages.

  18. Complement and renal transplantation : From donor to recipient

    NARCIS (Netherlands)

    Damman, Jeffrey; Schuurs, Theo A.; Ploeg, Rutger J.; Seelen, Marc A.

    2008-01-01

    Long-term kidney graft survival is affected by different variables including donor condition, ischemia-reperfusion injury, and graft rejection during the transplantation process. The complement system is an important mediator of renal ischemia-reperfusion injury and in rejecting allografts. However,

  19. Coreference relations in complex sentence with a complement clause

    Directory of Open Access Journals (Sweden)

    Moskovljević-Popović Jasmina D.

    2015-01-01

    Full Text Available The main purpose of this paper is to analyze different co reference relations which can be established in a complex sentence between one of the arguments of the matrix clause and the understood/implicit subject of the complement clause introduced by the complementizer “da”. Various patterns of control relations which are present in contemporary Serbian - obligatory, non-obligatory, and shared control - have been enumerated and exemplified. Different types of constructions and different classes of verbs which introduce (or may introduce control relations have been identified and patterns of control instantiated by them have been described. It has been argued that the analysis of the Serbian data indicates that a type of the matrix predicate is not the only factor which determines the control relations established in a complex sentence, but that a type of situation/event described in the complement clause, as well as the relationship between the events denoted by the matrix and the complement clauses have their influence too. [Projekat Ministarstva nauke Republike Srbije, br. 178004: Standardni srpski jezik: sintaksička, semantička i pragmatička istraživanja

  20. Complement activation by salivary agglutinin is secretor status dependent

    NARCIS (Netherlands)

    S.T.G. Gunput; A.J.M. Ligtenberg; B. Terlouw; M. Brouwer; E.C.I. Veerman; D. Wouters

    2015-01-01

    After mucosal damage or gingival inflammation, complement proteins leak into the oral cavity and mix with salivary proteins such as salivary agglutinin (SAG/gp-340/DMBT1). This protein is encoded by the gene Deleted in Malignant Brain Tumors 1 (DMBT1), and it aggregates bacteria, viruses and fungi,

  1. Nomenclature of the alternative activating pathway of complement*

    OpenAIRE

    1981-01-01

    This terminology note outlines for the first time a standard nomenclature for the alternative activating pathway of complement. It was drafted by a group of experts working under the auspices of the International Union of Immunological Societies (IUIS), and has been approved by the Nomenclature Committee of the IUIS.

  2. Multiple complementizers in Modern Danish and Middle English

    DEFF Research Database (Denmark)

    Nyvad, Anne Mette

    2016-01-01

    This paper expands the empirical coverage of the cP/CP-distinction proposed by Nyvad, Christensen & Vikner (2015) by applying it to a range of embedded clause types involving multiple complementizers in Middle English and Modern Danish, and offering a uniform analysis. Due to the fact that a number...

  3. Staphylococcal Proteases Aid in Evasion of the Human Complement System

    DEFF Research Database (Denmark)

    Jusko, Monika; Potempa, Jan; Kantyka, Tomasz;

    2014-01-01

    Staphylococcus aureus is an opportunistic pathogen that presents severe health care concerns due to the prevalence of multiple antibiotic-resistant strains. New treatment strategies are urgently needed, which requires an understanding of disease causation mechanisms. Complement is one of the first...

  4. Inhibition of zymosan-induced alternative complement pathway activation by concanavalin A.

    OpenAIRE

    Smith, M. C.; Pensky, J.; Naff, G. B.

    1982-01-01

    Zymosan, a polysaccharide composed primarily of glucan and mannan residues, activates the complement system through the alternative complement pathway. We showed that zymosan-induced complement activation is inhibited by zymosan-bound lectins with carbohydrate specificities for mannosyl and glycosyl residues. Lectins unable to bind mannosyl or glucosyl residues did not inhibit zymosan-induced complement activation.

  5. Kinetics of the unimolecular reaction of CH2OO and the bimolecular reactions with the water monomer, acetaldehyde and acetone under atmospheric conditions.

    Science.gov (United States)

    Berndt, Torsten; Kaethner, Ralf; Voigtländer, Jens; Stratmann, Frank; Pfeifle, Mark; Reichle, Patrick; Sipilä, Mikko; Kulmala, Markku; Olzmann, Matthias

    2015-08-14

    Stabilized Criegee Intermediates (sCIs) have been identified as oxidants of atmospheric trace gases such as SO2, NO2, carboxylic acids or carbonyls. The atmospheric sCI concentrations, and accordingly their importance for trace gas oxidation, are controlled by the rate of the most important loss processes, very likely the unimolecular reactions and the reaction with water vapour (monomer and dimer) ubiquitously present at high concentrations in the troposphere. In this study, the rate coefficients of the unimolecular reaction of the simplest sCI, formaldehyde oxide, CH2OO, and its bimolecular reaction with the water monomer have been experimentally determined at T = (297 ± 1) K and at atmospheric pressure by using a free-jet flow system. CH2OO was produced by the reaction of ozone with C2H4, and CH2OO concentrations were probed indirectly by detecting H2SO4 after titration with SO2. Time-resolved experiments yield a rate coefficient of the unimolecular reaction of k(uni) = (0.19 ± 0.07) s(-1), a value that is supported by quantum-chemical and statistical rate theory calculations as well as by additional measurements performed under CH2OO steady-state conditions. A rate coefficient of k(CH2OO+H2O) = (3.2 ± 1.2) × 10(-16) cm(3) molecule(-1) s(-1) has been determined for sufficiently low H2O concentrations (<10(15) molecule cm(-3)) that allow separation from the CH2OO reaction with the water dimer. In order to evaluate the accuracy of the experimental approach, the rate coefficients of the reactions with acetaldehyde and acetone were reinvestigated. The obtained rate coefficients k(CH2OO+acetald) = (1.7 ± 0.5) × 10(-12) and k(CH2OO+acetone) = (3.4 ± 0.9) × 10(-13) cm(3) molecule(-1) s(-1) are in good agreement with literature data. PMID:26159709

  6. Alternative complement pathway deregulation is correlated with dengue severity.

    Directory of Open Access Journals (Sweden)

    Eduardo J M Nascimento

    Full Text Available BACKGROUND: The complement system, a key component that links the innate and adaptive immune responses, has three pathways: the classical, lectin, and alternative pathways. In the present study, we have analyzed the levels of various complement components in blood samples from dengue fever (DF and dengue hemorrhagic fever (DHF patients and found that the level of complement activation is associated with disease severity. METHODS AND RESULTS: Patients with DHF had lower levels of complement factor 3 (C3; p = 0.002 and increased levels of C3a, C4a and C5a (p<0.0001 when compared to those with the less severe form, DF. There were no significant differences between DF and DHF patients in the levels of C1q, immunocomplexes (CIC-CIq and CRP. However, small but statistically significant differences were detected in the levels of MBL. In contrast, the levels of two regulatory proteins of the alternative pathway varied widely between DF and DHF patients: DHF patients had higher levels of factor D (p = 0.01, which cleaves factor B to yield the active (C3bBb C3 convertase, and lower levels of factor H (p = 0.03, which inactivates the (C3bBb C3 convertase, than did DF patients. When we considered the levels of factors D and H together as an indicator of (C3bBb C3 convertase regulation, we found that the plasma levels of these regulatory proteins in DHF patients favored the formation of the (C3bBb C3 convertase, whereas its formation was inhibited in DF patients (p<0.0001. CONCLUSION: The data suggest that an imbalance in the levels of regulatory factors D and H is associated with an abnormal regulation of complement activity in DHF patients.

  7. Licensing clausal complements : The case of Russian čto-clauses

    OpenAIRE

    Knyazev, M

    2016-01-01

    This dissertation describes and explains the distribution of Russian complement clauses with the complementizer čto. It is shown that complement clauses with čto display distributional restrictions that are not manifested by their English and Dutch counterparts and that do not follow from the standard account of complement clauses in the literature. Two classes of environments are discussed where such restrictions are observed, namely, complements of speech act verbs in their non-agentive use...

  8. Infections of People with Complement Deficiencies and Patients Who Have Undergone Splenectomy

    OpenAIRE

    Ram, Sanjay; Lewis, Lisa A.; Rice, Peter A.

    2010-01-01

    Summary: The complement system comprises several fluid-phase and membrane-associated proteins. Under physiological conditions, activation of the fluid-phase components of complement is maintained under tight control and complement activation occurs primarily on surfaces recognized as “nonself” in an attempt to minimize damage to bystander host cells. Membrane complement components act to limit complement activation on host cells or to facilitate uptake of antigens or microbes “tagged” with co...

  9. Interallelic complementation at the Drosophila melanogaster gastrulation defective locus defines discrete functional domains of the protein.

    OpenAIRE

    Ponomareff, G; Giordano, H; DeLotto, Y.; DeLotto, R

    2001-01-01

    The gastrulation defective (gd) locus encodes a novel serine protease that is involved in specifying the dorsal-ventral axis during embryonic development. Mutant alleles of gd have been classified into three complementation groups, two of which exhibit strong interallelic (intragenic) complementation. To understand the molecular basis of this interallelic complementation, we examined the complementation behavior of additional mutant alleles and sequenced alleles in all complementation groups....

  10. Complement receptor expression and activation of the complement cascade on B lymphocytes from patients with systemic lupus erythematosus (SLE)

    DEFF Research Database (Denmark)

    Marquart, H V; Svendsen, Anders Jørgen; Rasmussen, J M;

    1995-01-01

    It has previously been reported that the expression of the complement receptors, CR1 on erythrocytes and blood leucocytes and CR2 on B cells, is reduced in patients with SLE, and that the reduced expression of CR1 on erythrocytes is related to disease activity. We have earlier demonstrated that n...

  11. Pasteurella pneumotropica evades the human complement system by acquisition of the complement regulators factor H and C4BP.

    Directory of Open Access Journals (Sweden)

    Alfredo Sahagún-Ruiz

    Full Text Available Pasteurella pneumotropica is an opportunist Gram negative bacterium responsible for rodent pasteurellosis that affects upper respiratory, reproductive and digestive tracts of mammals. In animal care facilities the presence of P. pneumotropica causes severe to lethal infection in immunodeficient mice, being also a potential source for human contamination. Indeed, occupational exposure is one of the main causes of human infection by P. pneumotropica. The clinical presentation of the disease includes subcutaneous abscesses, respiratory tract colonization and systemic infections. Given the ability of P. pneumotropica to fully disseminate in the organism, it is quite relevant to study the role of the complement system to control the infection as well as the possible evasion mechanisms involved in bacterial survival. Here, we show for the first time that P. pneumotropica is able to survive the bactericidal activity of the human complement system. We observed that host regulatory complement C4BP and Factor H bind to the surface of P. pneumotropica, controlling the activation pathways regulating the formation and maintenance of C3-convertases. These results show that P. pneumotropica has evolved mechanisms to evade the human complement system that may increase the efficiency by which this pathogen is able to gain access to and colonize inner tissues where it may cause severe infections.

  12. Fluorescence of atopic allergens

    NARCIS (Netherlands)

    Berrens, L.

    1967-01-01

    Purified atopic allergens have been found to emit flue fluorescence upon irradiation with ultraviolet light of 365 mμ wavelength. The maximum of fluorescence is in the region 445–490 mμ and the intensity is of the same order of magnitude for different atopic allergens. Synthetic model compounds, inc

  13. Membranes and Fluorescence microscopy

    DEFF Research Database (Denmark)

    Bagatolli, Luis

    2009-01-01

    Fluorescence spectroscopy-based techniques using conventional fluorimeters have been extensively applied since the late 1960s to study different aspects of membrane-related phenomena, i.e., mainly relating to lipid-lipid and lipid-protein (peptide) interactions. Even though fluorescence...

  14. Hepatitis C virus NS3/4A protease inhibits complement activation by cleaving complement component 4.

    Directory of Open Access Journals (Sweden)

    Seiichi Mawatari

    Full Text Available BACKGROUND: It has been hypothesized that persistent hepatitis C virus (HCV infection is mediated in part by viral proteins that abrogate the host immune response, including the complement system, but the precise mechanisms are not well understood. We investigated whether HCV proteins are involved in the fragmentation of complement component 4 (C4, composed of subunits C4α, C4β, and C4γ, and the role of HCV proteins in complement activation. METHODS: Human C4 was incubated with HCV nonstructural (NS 3/4A protease, core, or NS5. Samples were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and then subjected to peptide sequencing. The activity of the classical complement pathway was examined using an erythrocyte hemolysis assay. The cleavage pattern of C4 in NS3/4A-expressing and HCV-infected cells, respectively, was also examined. RESULTS: HCV NS3/4A protease cleaved C4γ in a concentration-dependent manner, but viral core and NS5 did not. A specific inhibitor of NS3/4A protease reduced C4γ cleavage. NS3/4A protease-mediated cleavage of C4 inhibited classical pathway activation, which was abrogated by a NS3/4A protease inhibitor. In addition, co-transfection of cells with C4 and wild-type NS3/4A, but not a catalytic-site mutant of NS3/4A, produced cleaved C4γ fragments. Such C4 processing, with a concomitant reduction in levels of full-length C4γ, was also observed in HCV-infected cells expressing C4. CONCLUSIONS: C4 is a novel cellular substrate of the HCV NS3/4A protease. Understanding disturbances in the complement system mediated by NS3/4A protease may provide new insights into the mechanisms underlying persistent HCV infection.

  15. LucY: A Versatile New Fluorescent Reporter Protein.

    Directory of Open Access Journals (Sweden)

    Michele E Auldridge

    Full Text Available We report on the discovery, isolation, and use of a novel yellow fluorescent protein. Lucigen Yellow (LucY binds one FAD molecule within its core, thus shielding it from water and maintaining its structure so that fluorescence is 10-fold higher than freely soluble FAD. LucY displays excitation and emission spectra characteristic of FAD, with 3 excitation peaks at 276 nm, 377 nm, and 460 nm and a single emission peak at 530 nm. These excitation and emission maxima provide the large Stokes shift beneficial to fluorescence experimentation. LucY belongs to the MurB family of UDP-N-acetylenolpyruvylglucosamine reductases. The high resolution crystal structure shows that in contrast to other structurally resolved MurB enzymes, LucY does not contain a potentially quenching aromatic residue near the FAD isoalloxazine ring, which may explain its increased fluorescence over related proteins. Using E. coli as a system in which to develop LucY as a reporter, we show that it is amenable to circular permutation and use as a reporter of protein-protein interaction. Fragmentation between its distinct domains renders LucY non-fluorescent, but fluorescence can be partially restored by fusion of the fragments to interacting protein domains. Thus, LucY may find application in Protein-fragment Complementation Assays for evaluating protein-protein interactions.

  16. Complement or competition: Latino employment in a nontraditional settlement area.

    Science.gov (United States)

    Sanders, Jimy

    2012-01-01

    The migration of Latinos to nontraditional settlement areas in the United States is renewing interest in how an established low-skilled work force is affected by the inflow of a minority group whose members tend to have a weak basket of human capital. Some scholars focus on how the incoming group creates head-to-head competition with established workers. An alternative view posits that, depending on the context of the receiving labor market, incoming workers may primarily fill roles that complement preexisting labor market arrangements. I study these issues in the region of the country that has experienced the most pronounced in-migration of Latinos during the past few years. The findings indicate migrating Latinos tend to complement preexisting labor market conditions rather than spark job competition and undercut the earning power of non-Latinos. PMID:23017696

  17. Complements and the Wound Healing Cascade: An Updated Review

    Directory of Open Access Journals (Sweden)

    Hani Sinno

    2013-01-01

    Full Text Available Wound healing is a complex pathway of regulated reactions and cellular infiltrates. The mechanisms at play have been thoroughly studied but there is much still to learn. The health care system in the USA alone spends on average 9 billion dollars annually on treating of wounds. To help reduce patient morbidity and mortality related to abnormal or prolonged skin healing, an updated review and understanding of wound healing is essential. Recent works have helped shape the multistep process in wound healing and introduced various growth factors that can augment this process. The complement cascade has been shown to have a role in inflammation and has only recently been shown to augment wound healing. In this review, we have outlined the biology of wound healing and discussed the use of growth factors and the role of complements in this intricate pathway.

  18. Monotest in the complement fixation test: the Chorus system

    Directory of Open Access Journals (Sweden)

    Laura Meli

    2009-06-01

    Full Text Available The complement fixation test (CFT is a method used for the detection of antibodies against pathogens of infectious diseases, it has been proved to be a useful diagnostic method in the detection of acute disease in many medical laboratories.The test performed manually is time consuming and needs very skilled personnel.This study evaluates the automated Chorus CFT system with 87 serum samples in comparison with manual method using Virion-Serion reagents, against a panel of antigens, such as Adenovirus, Influenza A and B virus, Respiratory Syncythial Virus, Parainfluenza Mix, Mycoplasma Pneumoniae, and Echinococcus. The Chorus system includes standardized reagents and a monotest device to perform the single assay. In comparison to the manual CFT method, the correlation is 91.6% (7/83.The results obtained show that the automated Chorus system can be applied for detecting complement fixation antibodies against different infectious disease agents.

  19. Evaluation of complement proteins as screening markers for colorectal cancer

    DEFF Research Database (Denmark)

    Storm, Line; Christensen, Ib J; Jensenius, Jens C;

    2015-01-01

    BACKGROUND: Colorectal cancer (CRC) is a leading cause of cancer death worldwide. Lack of symptoms results in late detection and increased mortality. Inflammation, including complement activation, plays an important role in tumorigenesis. EXPERIMENTAL DESIGN: The concentrations of nine proteins of....... CONCLUSION: CL-L1, M-ficolin and MAp44 in combination discriminate between CRC and patients without cancer. The markers did not have sufficient discriminatory value for CRC detection, but may prove useful for screening when combined with other markers....

  20. Covalent binding and hemolytic activity of complement proteins.

    OpenAIRE

    Law, S K; Lichtenberg, N A; Levine, R P

    1980-01-01

    We report the inactivation of the third component of complement (C3) by hydroxylamine. C3 hemolytic and covalent binding activities decline with identical kinetics, demonstrating a direct correlation between the two activities. We conclude that covalent, surface-bound C3b is hemolytically active. The inactivation of C3 is first order with respect to hydroxylamine. We also studied C3 inactivation with [14C]methylamine. The inactivation corresponds quantitatively with the labeling of C3 in the ...

  1. Single nucleotide polymorphisms of complement component 5 and periodontitis

    OpenAIRE

    L. Chai; Zee, KY; Song, YQ; Leung, WK

    2010-01-01

    BACKGROUND AND OBJECTIVE: Polymorphisms of host defence genes might increase one's risks for periodontitis. This study investigated whether tagging single nucleotide polymorphisms (SNPs) of the gene encoding complement component 5 (C5) are associated with periodontitis in a Hong Kong Chinese population. MATERIAL AND METHODS: Eleven tagging SNPs of 229 patients with at least moderate periodontitis and 207 control subjects without periodontitis were genotyped using an i-plexGOLD MassARRAY mass-...

  2. The fundamental group of the complement of complexified real arrangements

    International Nuclear Information System (INIS)

    Let V be a finite dimensional vector space over the real or complex numbers. An arrangement in V is a finite collection of affine hyperplanes of V. Given a real arrangement A in a real vector space V. Then its complexification, AC, is a complex arrangement in the complex vector space VC, and will be called a complexified real arrangement. In this paper, we shall prove a presentation for the fundamental group of the complement of a complexified real arrangement. (author). 7 refs

  3. INFLATION AND UNEMPLOYMENT: ARE THEY COMPLEMENTS OR SUBSTITUTES?

    OpenAIRE

    Edwards, Clark

    1980-01-01

    Inflation and unemployment plagued the U S economy during the decade of the seventies Some economic models suggest that inflation and unemployment are bi-polar events - they cannot occur at the same time This article reviews two models that have been in the economics literature since the thirties and that explain inflation and unemployment as complements, not substitutes One is the well-known IS/LM framework, the other is sometimes called the structural unemployment framework A third model wh...

  4. Romanian passive participles as complements of perception verbs

    OpenAIRE

    D. Niculescu

    2013-01-01

    This article discusses the Romanian non-finite verbal forms which are complements of direct perception verbs: the gerundial and the past participle structures. The focus is on one restriction which the gerund displays, i.e. the fact that the passive morpheme fiind ‘being’ is ruled out after a direct perception verb, and the consequences thereof. Since the passive morpheme is absent from the direct perception configuration, the past participle encodes the passive event on its own. A series of ...

  5. Complement-dependent transport of antigen into B cell follicles

    DEFF Research Database (Denmark)

    Gonzalez, Santiago F.; Lukacs-Kornek, Veronika; Kuligowski, Michael P.;

    2010-01-01

    Since the original proposal by Fearon and Locksley (Fearon and Locksley. 1996. Science 272: 50-53) that the complement system linked innate and adaptive immunity, there has been a rapid expansion of studies on this topic. With the advance of intravital imaging, a number of recent papers revealed ...... opsonization of influenza and uptake by macrophages, and the capture of virus by dendritic cells residing in the medullary compartment of peripheral lymph nodes....

  6. Can Pulp Fibroblasts Kill Cariogenic Bacteria? Role of Complement Activation.

    Science.gov (United States)

    Jeanneau, C; Rufas, P; Rombouts, C; Giraud, T; Dejou, J; About, I

    2015-12-01

    Complement system activation has been shown to be involved in inflammation and regeneration processes that can be observed within the dental pulp after moderate carious decay. Studies simulating carious injuries in vitro have shown that when human pulp fibroblasts are stimulated by lipoteichoic acid (LTA), they synthetize all complement components. Complement activation leads to the formation of the membrane attack complex (MAC), which is known for its bacterial lytic effect. This work was designed to find out whether human pulp fibroblasts can kill Streptococcus mutans and Streptococcus sanguinis via complement activation. First, histological staining of carious tooth sections showed that the presence of S. mutans correlated with an intense MAC staining. Next, to simulate bacterial infection in vitro, human pulp fibroblasts were incubated in serum-free medium with LTA. Quantification by an enzymatic assay showed a significant increase of MAC formation on bacteria grown in this LTA-conditioned medium. To determine whether the MAC produced by pulp fibroblasts was functional, bacteria sensitivity to LTA-conditioned medium was evaluated using agar well diffusion assay and succinyl dehydrogenase (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide [MTT]) assay. Both assays showed that S. mutans and S. sanguinis were sensitive to LTA-conditioned medium. Finally, to evaluate whether MAC formation on cariogenic bacteria, by pulp fibroblasts, can be directly induced by the presence of these bacteria, a specific coculture model of human pulp fibroblasts and bacteria was developed. Immunofluorescence revealed an intense MAC labeling on bacteria after direct contact with pulp fibroblasts. The observed MAC formation and its lethal effects were significantly reduced when CD59, an inhibitor of MAC formation, was added. Our findings demonstrate that the MAC produced by LTA-stimulated pulp fibroblasts is functional and can kill S. mutans and S. sanguinis. Taken together

  7. Non-kinetic capabilities: complementing the kinetic prevalence to targeting

    OpenAIRE

    Ducheine, P.

    2014-01-01

    Targeting is used in military doctrine to describe a military operational way, using (military) means to influence a target (or addressee) in order to achieve designated political and/or military goals. The four factors italicized are used to analyse non-kinetic targeting, complementing our knowledge and understanding of the kinetic prevalence. Paradoxically, non-kinetic targeting is not recognized as a separate concept: kinetic and non-kinetic are intertwined facets of targeting. Kinetic tar...

  8. Generalized complement operators and applications in some semirings

    Energy Technology Data Exchange (ETDEWEB)

    Bijev, G. [Technical University of Sofia, 8, Kl.Ohridski Blvd, 1000 Sofia (Bulgaria)

    2013-12-18

    Generalized complement operators on the semiring of all Boolean matrices as semilattice homomorphisms are considered. Some applications in solving equations on the set Bn of all binary relations are developed. In particular the structure of B3 is investigated by computer methods. Specific properties of the subsemigroup generated by all irregular relations in B3 are found. Stochastic experiments on the monoid Bn were made. The frequency of irregular elements as well as those of solvable equations depending on n is examined.

  9. Generalized complement operators and applications in some semirings

    Science.gov (United States)

    Bijev, G.

    2013-12-01

    Generalized complement operators on the semiring of all Boolean matrices as semilattice homomorphisms are considered. Some applications in solving equations on the set Bn of all binary relations are developed. In particular the structure of B3 is investigated by computer methods. Specific properties of the subsemigroup generated by all irregular relations in B3 are found. Stochastic experiments on the monoid Bn were made. The frequency of irregular elements as well as those of solvable equations depending on n is examined.

  10. Altmetrics ¿a complement to conventional metrics

    OpenAIRE

    Melero, Remedios

    2015-01-01

    Emerging metrics based on article-level does not exclude traditional metrics based on citations to the journal, but complements them. Both can be employed in conjunction to offer a richer picture of an article use from immediate to long terms. Article-level metrics (ALM) is the result of the aggregation of different data sources and the collection of content from multiple social network services. Sources used for the aggregation can be broken down into five categories: usage, captures, mentio...

  11. Early Intra-Articular Complement Activation in Ankle Fractures

    Directory of Open Access Journals (Sweden)

    Hagen Schmal

    2014-01-01

    Full Text Available Cytokine regulation possibly influences long term outcome following ankle fractures, but little is known about synovial fracture biochemistry. Eight patients with an ankle dislocation fracture were included in a prospective case series and matched with patients suffering from grade 2 osteochondritis dissecans (OCD of the ankle. All fractures needed external fixation during which joint effusions were collected. Fluid analysis was done by ELISA measuring aggrecan, bFGF, IL-1β, IGF-1, and the complement components C3a, C5a, and C5b-9. The time periods between occurrence of fracture and collection of effusion were only significantly associated with synovial aggrecan and C5b-9 levels (P<0.001. Furthermore, synovial expressions of both proteins correlated with each other (P<0.001. Although IL-1β expression was relatively low, intra-articular levels correlated with C5a (P<0.01 and serological C-reactive protein concentrations 2 days after surgery (P<0.05. Joint effusions were initially dominated by neutrophils, but the portion of monocytes constantly increased reaching 50% at day 6 after fracture (P<0.02. Whereas aggrecan and IL-1β concentrations were not different in fracture and OCD patients, bFGF, IGF-1, and all complement components were significantly higher concentrated in ankle joints with fractures (P<0.01. Complement activation and inflammatory cell infiltration characterize the joint biology following acute ankle fractures.

  12. Early intra-articular complement activation in ankle fractures

    DEFF Research Database (Denmark)

    Schmal, Hagen; Salzmann, Gian M; Niemeyer, Philipp;

    2014-01-01

    Cytokine regulation possibly influences long term outcome following ankle fractures, but little is known about synovial fracture biochemistry. Eight patients with an ankle dislocation fracture were included in a prospective case series and matched with patients suffering from grade 2 osteochondri......Cytokine regulation possibly influences long term outcome following ankle fractures, but little is known about synovial fracture biochemistry. Eight patients with an ankle dislocation fracture were included in a prospective case series and matched with patients suffering from grade 2...... osteochondritis dissecans (OCD) of the ankle. All fractures needed external fixation during which joint effusions were collected. Fluid analysis was done by ELISA measuring aggrecan, bFGF, IL-1 β, IGF-1, and the complement components C3a, C5a, and C5b-9. The time periods between occurrence of fracture and...... and OCD patients, bFGF, IGF-1, and all complement components were significantly higher concentrated in ankle joints with fractures (P < 0.01). Complement activation and inflammatory cell infiltration characterize the joint biology following acute ankle fractures....

  13. Fluorescence and Spectral Imaging

    Directory of Open Access Journals (Sweden)

    Ralph S. DaCosta

    2007-01-01

    Full Text Available Early identification of dysplasia remains a critical goal for diagnostic endoscopy since early discovery directly improves patient survival because it allows endoscopic or surgical intervention with disease localized without lymph node involvement. Clinical studies have successfully used tissue autofluorescence with conventional white light endoscopy and biopsy for detecting adenomatous colonic polyps, differentiating benign hyperplastic from adenomas with acceptable sensitivity and specificity. In Barrett's esophagus, the detection of dysplasia remains problematic because of background inflammation, whereas in the squamous esophagus, autofluorescence imaging appears to be more dependable. Point fluorescence spectroscopy, although playing a crucial role in the pioneering mechanistic development of fluorescence endoscopic imaging, does not seem to have a current function in endoscopy because of its nontargeted sampling and suboptimal sensitivity and specificity. Other point spectroscopic modalities, such as Raman spectroscopy and elastic light scattering, continue to be evaluated in clinical studies, but still suffer the significant disadvantages of being random and nonimaging. A recent addition to the fluorescence endoscopic imaging arsenal is the use of confocal fluorescence endomicroscopy, which provides real-time optical biopsy for the first time. To improve detection of dysplasia in the gastrointestinal tract, a new and exciting development has been the use of exogenous fluorescence contrast probes that specifically target a variety of disease-related cellular biomarkers using conventional fluorescent dyes and novel potent fluorescent nanocrystals (i.e., quantum dots. This is an area of great promise, but still in its infancy, and preclinical studies are currently under way.

  14. The relative merits of therapies being developed to tackle inappropriate ('self'-directed) complement activation.

    Science.gov (United States)

    Antwi-Baffour, Samuel; Kyeremeh, Ransford; Adjei, Jonathan Kofi; Aryeh, Claudia; Kpentey, George

    2016-12-01

    The complement system is an enzyme cascade that helps defend against infection. Many complement proteins occur in serum as inactive enzyme precursors or reside on cell surfaces. Complement components have many biologic functions and their activation can eventually damage the plasma membranes of cells and some bacteria. Although a direct link between complement activation and autoimmune diseases has not been found, there is increasing evidence that complement activation significantly contributes to the pathogenesis of a large number of inflammatory diseases that may have autoimmune linkage. The inhibition of complement may therefore be very important in a variety of autoimmune diseases since their activation may be detrimental to the individual involved. However, a complete and long-term inhibition of complement may have some contra side effects such as increased susceptibility to infection. The site of complement activation will, however, determine the type of inhibitor to be used, its route of application and dosage level. Compared with conventional drugs, complement inhibitors may be the best option for treatment of autoimmune diseases. The review takes a critical look at the relative merits of therapies being developed to tackle inappropriate complement activation that are likely to result in sporadic autoimmune diseases or worsen already existing one. It covers the complement system, general aspects of complement inhibition therapy, therapeutic strategies and examples of complement inhibitors. It concludes by highlighting on the possibility that a better inhibitor of complement activation when found will help provide a formidable treatment for autoimmune diseases as well as preventing one. PMID:26935316

  15. Highly thermostable fluorescent proteins

    Science.gov (United States)

    Bradbury, Andrew M.; Waldo, Geoffrey S.; Kiss, Csaba

    2011-03-22

    Thermostable fluorescent proteins (TSFPs), methods for generating these and other stability-enhanced proteins, polynucleotides encoding such proteins, and assays and method for using the TSFPs and TSFP-encoding nucleic acid molecules are provided. The TSFPs of the invention show extremely enhanced levels of stability and thermotolerance. In one case, for example, a TSFP of the invention is so stable it can be heated to 99.degree. C. for short periods of time without denaturing, and retains 85% of its fluorescence when heated to 80.degree. C. for several minutes. The invention also provides a method for generating stability-enhanced variants of a protein, including but not limited to fluorescent proteins.

  16. Complement inhibitory proteins expression in placentas of thrombophilic women Complement inhibitory proteins expression in placentas of thrombophilic women

    Directory of Open Access Journals (Sweden)

    Przemysław Krzysztof Wirstlein

    2012-10-01

    Full Text Available Factors controlling complement activation appear to exert a protective effect on pregnancy. This is
    particularly important in women with thrombophilia. The aim of this study was to determine the transcript and
    protein levels of complement decay-accelerating factor (DAF and membrane cofactor protein (MCP in the
    placentas of women with acquired and inherited thrombophilia. Also, we assessed immunohistochemistry staining
    of inhibitors of the complement cascade, DAF and MCP proteins, in the placentas of thrombophilic women.
    Placentas were collected from eight women with inherited thrombophilia and ten with acquired thrombophilia.
    The levels of DAF and MCP transcripts were evaluated by qPCR, the protein level was evaluated by Western
    blot. We observed a higher transcript (p < 0.05 and protein (p < 0.001 levels of DAF and MCP in the placentas
    of thrombophilic women than in the control group. DAF and MCP were localized on villous syncytiotrophoblast
    membranes, but the assessment of staining in all groups did not differ. The observed higher expression level of
    proteins that control activation of complement control proteins is only seemingly contradictory to the changes
    observed for example in the antiphospholipid syndrome. However, given the hitherto known biochemical changes
    associated with thrombophilia, a mechanism in which increased expression of DAF and MCP in the placentas is
    an effect of proinflammatory cytokines, which accompanies thrombophilia, is probable.Factors controlling complement activation appear to exert a protective effect on pregnancy. This is
    particularly important in women with thrombophilia. The aim of this study was to determine the transcript and
    protein levels of complement decay-accelerating factor (DAF and membrane cofactor protein (MCP in the
    placentas of women with acquired and inherited thrombophilia. Also, we assessed immunohistochemistry

  17. Fluorescence quenching of uric acid solubilized in bicontinuous microemulsion by nitrobenzene

    Directory of Open Access Journals (Sweden)

    Maurice O. Iwunze

    2013-02-01

    Full Text Available Abstract: Uric Acid is known to be practically insoluble in aqueous and alcoholic media. However, it exhibits a reasonable solubility in a Bicontinuous Microemulsion system – a 15-fold or more increase in solubility in this system compared to its solubility in water. The bicontinuous microemulsion is made up of three components –Dodecane-Surfactant-water. Uric acid solubilized in this system is quenched by nitrobenzene. The obtained fluorescence data do not obey the Stern-Volmer equation when plotted accordingly. Therefore, the modified Stern-Volmer equation was used to analyze the data. It was observed that only one third (1/3 of uric acid is accessible to quenching in this medium and the reaction is diffusion-limited. The Stern-Volmer quenching constant, KSV, was calculated to be 130 M-1 and the fluorescence lifetime, 0, the quantum yield,, and the bimolecular quenching rate constant, kq, were calculated as 10.6 nanoseconds, 0.06 and 1.231010 M-1s-1, respectively.

  18. Fluorescent filtered electrophosphorescence

    Science.gov (United States)

    Forrest, Stephen R.; Sun, Yiru; Giebink, Noel; Thompson, Mark E.

    2009-01-06

    The present invention relates to organic light emitting devices (OLEDs), and more specifically to OLEDS that emit light using a combination of fluorescent emitters and phosphorescent emitters for the efficient utilization of all of the electrically generated excitons.

  19. Fluorescence fluctuation immunoassay.

    Science.gov (United States)

    Elings, V B; Nicoli, D F; Briggs, J

    1983-01-01

    The homogeneous fluorescent immunoassay described above allows one to measure the brightness of fluorescently tagged carrier particles that are suspended in a background of free, unbound fluorescent sources. We have demonstrated the feasibility of our technique using a gentamicin competitive assay as well as idealized model systems. We have seen that the fluctuation-correlation method is able to discriminate against free background sources because each fluorescing particle in solution contributes to the correlation peak [Eq. (4)] with a weighting equal to the square of its respective intensity. Hence, a few very bright sources contribute disproportionately to the "signal" relative to many weak ones. To take advantage of this property, one would therefore design an assay that uses relatively larger carrier particles, each of which is capable of binding on the order of 10(3) to 10(4) tagged antibodies or antigens. Unfortunately, the nonlinear dependence of the correlation peak on the brightness of the fluorescing species causes the technique to be perturbed by carrier particle aggregation; the apparent bound fluorescence intensity increases with the extent of aggregation. The latter may be an unavoidable consequence of performing assays using raw blood serum, for example. The ultimate usefulness of this method will depend on its sensitivity and speed when applied to "real" assays of clinical significance. These characteristics will be influenced by a number of technical details. Given our limited experience with the method thus far, it would appear that its principal drawback is its relatively slow speed. In order to decrease the time needed for a reliable measurement, one must average the random fluctuations in the fluorescent intensity to zero more quickly. In principle, this can be accomplished by decreasing the shot noise by collecting a larger fraction of the fluorescent light, and increasing the sampling rate. The method requires rather complicated

  20. Stochastic Micro-Pattern for Automated Correlative Fluorescence - Scanning Electron Microscopy.

    Science.gov (United States)

    Begemann, Isabell; Viplav, Abhiyan; Rasch, Christiane; Galic, Milos

    2015-01-01

    Studies of cellular surface features gain from correlative approaches, where live cell information acquired by fluorescence light microscopy is complemented by ultrastructural information from scanning electron micrographs. Current approaches to spatially align fluorescence images with scanning electron micrographs are technically challenging and often cost or time-intensive. Relying exclusively on open-source software and equipment available in a standard lab, we have developed a method for rapid, software-assisted alignment of fluorescence images with the corresponding scanning electron micrographs via a stochastic gold micro-pattern. Here, we provide detailed instructions for micro-pattern production and image processing, troubleshooting for critical intermediate steps, and examples of membrane ultra-structures aligned with the fluorescence signal of proteins enriched at such sites. Together, the presented method for correlative fluorescence - scanning electron microscopy is versatile, robust and easily integrated into existing workflows, permitting image alignment with accuracy comparable to existing approaches with negligible investment of time or capital. PMID:26647824

  1. Complement activation associated with polysorbate 80 in beagle dogs.

    Science.gov (United States)

    Qiu, Shidong; Liu, Zhaohua; Hou, Li; Li, Yuanyuan; Wang, Jiao; Wang, Hong; Du, Wu; Wang, Wenfang; Qin, Yizhuo; Liu, Zhaoping

    2013-01-01

    Polysorbate 80 (Tween® 80) is the most extensively used surfactant in parenteral drug formulation. Its application as an adjunct for intravenous drug administration is approved by the Food and Drug Administration. However, severe hypersensitive reactions, which are typical non-immune anaphylactic reactions (pseudoallergy) characterized by the release of histamine and unvaried IgE antibodies, have been associated with Tween® 80. In order to explore the non-immune anaphylactic mechanisms of Tween® 80, we performed in vivo experiments to assess the changes in physiological and hematologic indicators after intravenous injection of Tween® 80 into dogs. Tween® 80 induced the release of histamine, and a 2-fold increase in SC5b-9, 2.5-fold increase in C4d, 1.3-fold increase in Bb, while IgE remained unchanged. It also produced changes in pulmonary pressure, systemic pressure and ECG. In in vitro experiments, Tween® 80 was incubated with dog serum in the presence of an inhibitor of complement activation (EGTA/Mg(2+)). Under these conditions, Tween® 80 increased the contents of C4d and Bb. The results of this study reveal that Tween® 80 can cause cardiopulmonary distress in dogs and activate the complement system through classical and alternative pathways as indicated in both in vivo and in vitro preparations. Moreover, they demonstrate the utility of the beagle dog as an animal model for the study of complement activation-related pseudoallergy. These findings raise concerns with regard to the indiscriminate use of Tween® 80 in clinical applications. PMID:23159336

  2. Vasculitides and the Complement System: a Comprehensive Review.

    Science.gov (United States)

    Chimenti, Maria Sole; Ballanti, Eleonora; Triggianese, Paola; Perricone, Roberto

    2015-12-01

    Systemic vasculitides are a group of rare diseases characterized by inflammation of the arterial or venous vessel wall, causing stenosis or thrombosis. Clinical symptoms may be limited to skin or to other organs or may include multiple manifestations as systemic conditions. The pathogenesis is related to the presence of leukocytes in the vessels and to the IC deposition, which implies the activation of the complement system (CS) and then the swelling and damage of vessel mural structures. The complement system (CS) is involved in the pathogenesis of several autoimmune diseases, including systemic vasculitides. This enzymatic system is a part of the innate immune system, and its function is linked to the modulation of the adaptive immunity and in bridging innate and adaptive responses. Its activation is also critical for the development of natural antibodies and T cell response and for the regulation of autoreactive B cells. Complement triggering contributes to inflammation-driven tissue injury, which occurs during the ischemia/reperfusion processes, vasculitides, nephritis, arthritis, and many others diseases. In systemic vasculitides, a group of uncommon diseases characterized by blood vessel inflammation, the contribution of CS in the development of inflammatory damage has been demonstrated. Treatment is mainly based on clinical manifestations and severity of organ involvement. Evidences on the efficacy of traditional immunosuppressive therapies have been collected as well as data from clinical trials that involve the modulation of the CS. In particular in small-medium-vessel vasculitides, the CS represents an attractive target. Herein, we reviewed the pathogenetic role of CS in these systemic vasculitides as urticarial vasculitis, ANCA-associated vasculitides, anti-glomerular basement membrane disease, cryoglobulinaemic vasculitides, Henoch-Schönlein purpura/IgA nephropathy, and Kawasaki disease and therefore its potential therapeutic use in this context. PMID

  3. Xeroderma pigmentosum complementation group G associated with Cockayne syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Vermeulen, W.; Jaspers, N.G.J.; Bootsma, D.; Hoeijmakers, J.H.J. (Erasmus Univ., Rotterdam (Belgium)); Jaeken, J. (Univ. Hospital Gasthuisberg, Leuven (Belgium))

    1993-07-01

    Xeroderma pigmentosum (XP) and Cockayne syndrome (CS) are two rare inherited disorders with a clinical and cellular hypersensitivity to the UV component of the sunlight spectrum. Although the two traits are generally considered as clinically and genetically distinct entities, on the biochemical level a defect in the nucleotide excision-repair (NER) pathway is involved in both. Classical CS patients are primarily deficient in the preferential repair of DNA damage in actively transcribed genes, whereas in most XP patients the genetic defect affects both [open quotes]preferential[close quotes] and [open quotes]overall[close quotes] NER modalities. Here the authors report a genetic study of two unrelated, severely affected patients with the clinical characteristics of CS but with a biochemical defect typical of XP. By complementation analysis, using somatic cell fusion and nuclear microinjection of cloned repair genes, they assign these two patients to XP complementation group G, which previously was not associated with CS. This observation extends the earlier identification of two patients with a rare combined XP/CS phenotype within XP complementation groups B and D, respectively. It indicates that some mutations in at least three of the seven genes known to be involved in XP also can result in a picture of partial or even full-blown CS. It is concluded that the syndromes XP and CS are biochemically closely related and may be part of a broader clinical disease spectrum. The authors suggest, as a possible molecular mechanism underlying this relation, that the XPGC repair gene has an additional vital function, as shown for some other NER genes. 33 refs., 5 tabs.

  4. Molecular Basis for Complement Recognition and Inhibition Determined by Crystallographic Studies of the Staphylococcal Complement Inhibitor (SCIN) Bound to C3c and C3b

    OpenAIRE

    Garcia, Brandon L.; Ramyar, Kasra X.; Tzekou, Apostolia; Ricklin, Daniel; McWhorter, William J.; Lambris, John D.; Geisbrecht, Brian V.

    2010-01-01

    The human complement system plays an essential role in innate and adaptive immunity by marking and eliminating microbial intruders. Activation of complement on foreign surfaces results in proteolytic cleavage of complement component 3 (C3) into the potent opsonin C3b, which triggers a variety of immune responses and participates in a self-amplification loop mediated by a multi-protein assembly known as the C3 convertase. The human pathogen Staphylococcus aureus has evolved a sophisticated and...

  5. Investigation of Interaction of Vaccinia Virus Complement Control Protein and Curcumin with Complement Components C3 and C3b Using Quartz Crystal Microbalance with Dissipation Monitoring Technology

    OpenAIRE

    Kulkarni, Amod P.; Randall, Philippa J.; Murthy, Krishna; Kellaway, Lauriston A; Kotwal, Girish J.

    2010-01-01

    C3 and C3b, the components central to the complement activation, also play a damaging role in several inflammatory disorders. Vaccinia virus complement control protein (VCP) and curcumin (Cur) are natural compounds with different biological origins reported to regulate complement activation. However, both VCP and Cur have not been investigated for their interaction with the third component (C3) prior to it being converted to its activated form (C3b). These two compounds have also not been com...

  6. Employing the fluorescence anisotropy and quenching kinetics of tryptophan to hunt for residual structures in denatured proteins

    Indian Academy of Sciences (India)

    Satish Kumar; Rajaram Swaminathan

    2007-03-01

    Residual structures in denatured proteins have acquired importance in recent years owing to their role as protein-folding initiation sites. Locating these structures in proteins has proved quite formidable, requiring techniques like NMR. Here in this report, we take advantage of the ubiquitous presence of tryptophan residues in residual structures to hunt for their presence using steady-state fluorescence spectroscopy. The surface accessibility and rotational dynamics of tryptophan in putative residual structures among ten different proteins, namely glucagon, melittin, subtilisin carlsberg, myelin basic protein, ribonuclease T1, human serum albumin, barstar mutant, bovine serum albumin, lysozyme and Trp-Met-Asp-Phe-NH2 peptide, was studied using steady state fluorescence quenching and anisotropy, respectively. Five proteins, namely ribonuclease T1, bovine serum albumin, melittin, barstar and hen egg white lysozyme appear likely to possess tryptophan(s) in hydrophobic clusters based on their reduced bimolecular quenching rates and higher steady-state anisotropy in proportion to their chain length. We also show that the fluorescence emission maximum of tryptophan is insensitive to the presence of residual structures.

  7. Contribution to the study of immune hemolysis by toad complement

    Directory of Open Access Journals (Sweden)

    Marisa Gennari

    1982-09-01

    Full Text Available EA (sheep erythrocytes carrying rabbit antibody are lysed by toad complement under optimal conditions which include a low concentration of cells (1.54 x 10*8/ml, a low temperature of incubation (30°C and the same amounts of Ca++ and Mg++ as required for the titration of guinea-pig complement. Kinetic studies of the role of cations mentioned above in immune lysis by toad C have disclosed a fundamental difference as compared to guinea-pig C. In a limited complement system, the lysis by amphibian C is completely blocked by EDTA, even when the chelating agent is added as late as 15 minutes after zero-time. Inhibition by EGTA is only partial and the findings suggest that Mg++ is required not only at the beginning, but also at late stages of the lytic process. It has been speculated that the activation of amphibian complement proceeds mainly by the alternative pathway.EA (eritrócitos de carneiro, sensibilizados com anticorpos de coelho são lisados por complemento de sapo em condições ótimas, que consistem no uso de uma baixa concentração de células (1.54 x 10*8/ml, incubação a baixa temperatura (30°C e as mesmas quantidades de Ca++ e de Mg++, requeridas para a titulação da atividade hemolítica do complemento de cobaia. Estudos cinéticos do efeito dos cátions mencionados acima na imune-lise produzida pelo complemento de sapo revelam uma diferença fundamental com relação ao complemento de cobaía. Num sistema limitado pela quantidade de complemento, a lise pelo C de anfíbio é totalmente bloqueada por EDTA, mesmo quando a adição do agente quelante é feita após 15 minutos, ao passo que com EGTA o bloqueio é apenas parcial. Os achados experimentais sugerem que Mg++ seja requerido não apenas no estágio inicial, mas também em estágios tardios do processo lítico e permitem especular que a ativação do complemento de anfíbio se processa predominantemente pela via alternativa.

  8. The role of complement in the acquired immune response

    DEFF Research Database (Denmark)

    Nielsen, C H; Fischer, E M; Leslie, R G

    2000-01-01

    specific T cells; the activation of a CD21/CD19 complex-mediated signalling pathway in B cells, which provides a stimulus synergistic to that induced by antigen interaction with the B-cell receptor (BCR); and promotion of the interaction between B cells and FDC, where C3d-bearing immune complexes...... participate in intercellular bridging. Finally, current studies suggest that CR2 may also play a role in the determination of B-cell tolerance towards self-antigens and thereby hold the key to the previously observed correlation between deficiencies of the early complement components and autoimmune disease....

  9. Molecular basis of complement C3 deficiency in guinea pigs.

    OpenAIRE

    Auerbach, H S; de Burger, R; Dodds, A.; Colten, H R

    1990-01-01

    In experiments to ascertain the biochemical basis of a genetically determined deficiency of the third component of complement (C3) in guinea pigs, we found that C3-deficient liver and peritoneal macrophages contain C3 messenger RNA of normal size (approximately 5 kb) and amounts, that this mRNA programs synthesis of pro-C3 in oocytes primed with liver RNA and in primary macrophage cultures. In each instance, heterodimeric native C3 protein was secreted with normal kinetics but the C3 protein ...

  10. Approximate Schur complement preconditioning of the lowest order nodal discretizations

    Energy Technology Data Exchange (ETDEWEB)

    Moulton, J.D.; Ascher, U.M. [Univ. of British Columbia, Vancouver, British Columbia (Canada); Morel, J.E. [Los Alamos National Lab., NM (United States)

    1996-12-31

    Particular classes of nodal methods and mixed hybrid finite element methods lead to equivalent, robust and accurate discretizations of 2nd order elliptic PDEs. However, widespread popularity of these discretizations has been hindered by the awkward linear systems which result. The present work exploits this awkwardness, which provides a natural partitioning of the linear system, by defining two optimal preconditioners based on approximate Schur complements. Central to the optimal performance of these preconditioners is their sparsity structure which is compatible with Dendy`s black box multigrid code.

  11. Quaternions, hexadecanions and the Schur complement in quantum mechanics

    International Nuclear Information System (INIS)

    We review the mathematical object invented by Sir William Rowan Hamilton, which he called quaternion, and we study its association with the matrix structure known as complement of Schur. We analyze the positivity of quaternions when represented by 2 × 2 matrices. We extend this very concept to the larger mathematical object, which generalizes the quaternion, the hexadecanion, which we shall define and use. We apply Schur's method to a quantum state that describes a beam of particles characterized by discrete degrees of freedom, the internal parity and the spin, as proposed by Lee and Yang (1956 Phys. Rev. 104 822). (paper)

  12. Selection of functional cDNAs by complementation in yeast.

    OpenAIRE

    McKnight, G L; McConaughy, B L

    1983-01-01

    Yeast cDNA was prepared in a yeast expression plasmid to generate a cDNA plasmid pool composed of approximately 40,000 members. Several yeast mutants were transformed with the cDNA plasmid pool, and the cDNAs for ADC1, HIS3, URA3, and ASP5 were isolated by functional complementation. Restriction enzyme analysis confirmed the genetic identity of the ADC1, HIS3, and URA3 cDNAs and demonstrated that the URA3 cDNA contains 5' noncoding sequences. The relative abundance of the various cDNAs in the...

  13. Fluorescence enhancement of N2O2-type dipyrrin ligand in two step responding to zinc(II) ion

    International Nuclear Information System (INIS)

    Fluorescence imaging is well-suited for the live imaging of biological Zn(II), which has no facile spectroscopic or magnetic signature. The successful application of this methodology requires the development of robust Zn(II) imaging agents that display high sensitivity, selectivity and temporal fidelity. In this study, a N2O2-type dipyrrin based bimolecular zinc(II) complex was produced and shown to have sharper, blue-shifted and more enhanced fluorescence emission. An approximate three-fold fluorescence enhancement was achieved within the micromolar concentration range, which is an important parameter for Zn(II) detection in vivo. The increase in emission intensity was due to the dominant role of aryl-ring rotation in governing the excited state dynamics and fluorescence properties of the dipyrrin dye. Fluorescence titration showed that the ligand complex exhibited very strong zinc(II) binding affinity when compared to that in the binuclear chloro complex. The fluorescence emission changes in the dipyrrin dye to zinc(II) ion could be observed not only using instruments but also by the naked-eye (violet→sky blue). - Graphical abstract: A N2O2-type dipyrrin (BB2) has been shown to have sharper, blue-shifted and more enhanced fluorescence emission upon treatment of Zn(II) salt with the detection limit (LOD) of ca. 4.2 nM. Fluorescence response of BB2 upon zinc complex formation can be observed by the naked-eye. Highlights: ► The fluorophore ligand, N2O2-type dipyrrin (BB2), showed two step responses to zinc(II) ion. ► Addition of 0.2 equiv. of ZnCl2 to BB2 immediately increased the fluorescence intensity. ► Only micromolar concentrations of ZnCl2 were needed to achieve 3-fold fluorescence enhancement. ► Fluorescence response of the substituted dipyrrin dye upon zinc complex formation can be observed by the naked-eye. ► High optical brightness, high binding constant and very low detection limit values make BB2 as selective sensor for Zn(II) detection.

  14. The visible touch: in planta visualization of protein-protein interactions by fluorophore-based methods

    OpenAIRE

    Panstruga Ralph; Lahaye Thomas; Bhat Riyaz A

    2006-01-01

    Abstract Non-invasive fluorophore-based protein interaction assays like fluorescence resonance energy transfer (FRET) and bimolecular fluorescence complementation (BiFC, also referred to as "split YFP") have been proven invaluable tools to study protein-protein interactions in living cells. Both methods are now frequently used in the plant sciences and are likely to develop into standard techniques for the identification, verification and in-depth analysis of polypeptide interactions. In this...

  15. Ulex europaeus agglutinin II (UEA-II) is a novel, potent inhibitor of complement activation

    OpenAIRE

    Lekowski, Robert; Collard, Charles D.; Reenstra, Wende R.; Stahl, Gregory L.

    2001-01-01

    Complement is an important mediator of vascular injury following oxidative stress. We recently demonstrated that complement activation following endothelial oxidative stress is mediated by mannose-binding lectin (MBL) and activation of the lectin complement pathway. Here, we investigated whether nine plant lectins which have a binding profile similar to that of MBL competitively inhibit MBL deposition and subsequent complement activation following human umbilical vein endothelial cell (HUVEC)...

  16. PRELIMINARY INVESTIGATION ABOUT THE ANTI-COMPLEMENT PROPERTIES OF PARTIALLY SEPARATED Vipera ammodytes VENOM

    Directory of Open Access Journals (Sweden)

    S. STANILOVA

    1997-01-01

    Full Text Available The present study demonstrates that Vipera ammodytes venom is a potent inhibitor of human complement activation. Crude venom was fractionated by ion-exchange chromatography and each fraction was then tested for proteolytic, hemolytic and anti-complement activities. Three peaks decreased the hemolytic activity of human serum when measured using assays for the classical and alternative pathways of activation. One of the anti-complement peaks contains a protease capable of cleaving the C3 component of complement.

  17. Comparison of Three Different Methods for Measuring Classical Pathway Complement Activity

    OpenAIRE

    Jaskowski, Troy D; Martins, Thomas B; Litwin, Christine M.; Hill, Harry R.

    1999-01-01

    The complement system plays an important role in host defense against infection and in most inflammatory processes. The standard 50% hemolytic complement (CH50) assay is the most commonly used method of screening patient sera for functional activity of the classical complement pathway. Our objective in this study was to compare two newer methods (the enzyme immunoassay and the liposome immunoassay) to a commercial CH50 assay for measuring total classical complement activity. We conclude that ...

  18. Impact of reducing complement inhibitor binding on the immunogenicity of native neisseria meningitidis outer membrane vesicles

    OpenAIRE

    Daniels-Treffandier, H; Nie, K.; Marsay, L.; Dold, C.; Sadarangani, M.; Reyes-Sandoval, A.; Langford, PR; Wyllie, D; Hill, F; Pollard, AJ; Rollier, CS

    2016-01-01

    Neisseria meningitidis recruits host human complement inhibitors to its surface to down-regulate complement activation and enhance survival in blood. We have investigated whether such complement inhibitor binding occurs after vaccination with native outer membrane vesicles (nOMVs), and limits immunogenicity of such vaccines. To this end, nOMVs reactogenic lipopolysaccharide was detoxified by deletion of the lpxl1 gene (nOMVlpxl1). nOMVs unable to bind human complement factor H (hfH) were gene...

  19. A NEW METHOD TO ASSESS FUNCTIONAL ACTIVITY OF SERUM COMPLEMENT SYSTEM

    OpenAIRE

    E. G. Cheremnykh; Ivanov, P. A.; M. I. Faktor; N. S. Karpova; E. F. Vasiljeva; K. V. Gusev; O. S. Brusov

    2015-01-01

    Complement system is an important component of innate immunity, providing primary protection against pathogens invading the body. In addition, it was shown that the complement system is associated with many diseases, not only autoimmune and infectious, but also mental disorders. In this regard, it is necessary to develop affordable and fast method of measuring activity of the complement system in real-time mode. We present a new semi-automated method for assessment of serum complement activit...

  20. The Emerging Role of Complement Lectin Pathway in Trypanosomatids: Molecular Bases in Activation, Genetic Deficiencies, Susceptibility to Infection, and Complement System-Based Therapeutics

    Directory of Open Access Journals (Sweden)

    Ingrid Evans-Osses

    2013-01-01

    Full Text Available The innate immune system is evolutionary and ancient and is the pivotal line of the host defense system to protect against invading pathogens and abnormal self-derived components. Cellular and molecular components are involved in recognition and effector mechanisms for a successful innate immune response. The complement lectin pathway (CLP was discovered in 1990. These new components at the complement world are very efficient. Mannan-binding lectin (MBL and ficolin not only recognize many molecular patterns of pathogens rapidly to activate complement but also display several strategies to evade innate immunity. Many studies have shown a relation between the deficit of complement factors and susceptibility to infection. The recently discovered CLP was shown to be important in host defense against protozoan microbes. Although the recognition of pathogen-associated molecular patterns by MBL and Ficolins reveal efficient complement activations, an increase in deficiency of complement factors and diversity of parasite strategies of immune evasion demonstrate the unsuccessful effort to control the infection. In the present paper, we will discuss basic aspects of complement activation, the structure of the lectin pathway components, genetic deficiency of complement factors, and new therapeutic opportunities to target the complement system to control infection.

  1. Biological applications of fluorescence lifetime imaging beyond microscopy

    Science.gov (United States)

    Akers, Walter J.; Berezin, Mikhail Y.; Lee, Hyeran; Guo, Kevin; Almutairi, Adah; Fréchet, Jean M. J.; Fischer, Georg M.; Daltrozzo, Ewald; Achilefu, Samuel

    2010-02-01

    Fluorescence lifetime is a relatively new contrast mechanism for optical imaging in living subjects that relies on intrinsic properties of fluorophores rather than concentration dependent intensity. Drawing upon the success of fluorescence lifetime imaging microscopy (FLIM) for investigation of protein-protein interactions and intracellular physiology, in vivo fluorescence lifetime imaging (FLI) promises to dramatically increase the utility of fluorescencebased imaging in preclinical and clinical applications. Intrinsic fluorescence lifetime measurements in living tissues can distinguish pathologies such as cancer from healthy tissue. Unfortunately, intrinsic FLT contrast is limited to superficial measurements. Conventional intensity-based agents have been reported for measuring these phenomena in vitro, but translation into living animals is difficult due to optical properties of tissues. For this reason, contrast agents that can be detected in the near infrared (NIR) wavelengths are being developed by our lab and others to enhance the capabilities of this modality. FLT is less affected by concentration and thus is better for detecting small changes in physiology, as long as sufficient fluorescence signal can be measured. FLT can also improve localization of signals for improved deep tissue imaging. Examples of the utility of exogenous contrast agents will be discussed, including applications in monitoring physiologic functions, controlled drug release and cancer biology. Instrumentation for FLI will also be discussed, including planar and diffuse optical imaging in time and frequency domains. Future applications will also be discussed that are being developed in this exciting field that complement other optical modalities.

  2. DMPD: Complement-mediated phagocytosis--the role of Syk. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 16754322 Complement-mediated phagocytosis--the role of Syk. Tohyama Y, Yamamura H. ...IUBMB Life. 2006 May-Jun;58(5-6):304-8. (.png) (.svg) (.html) (.csml) Show Complement-mediated phagocytosis--the role... of Syk. PubmedID 16754322 Title Complement-mediated phagocytosis--the role of Syk. Authors Tohyama

  3. Dysregulation of adaptive immune responses in complement C3-deficient patients

    NARCIS (Netherlands)

    Pekkarinen, Pirkka T.; Heikkila, Nelli; Kisand, Kai; Peterson, Paert; Botto, Marina; Daha, Mohamed R.; Drouet, Christian; Isaac, Lourdes; Helminen, Merja; Haahtela, Tari; Meri, Seppo; Jarva, Hanna; Arstila, T. Petteri

    2015-01-01

    In addition to its effector functions, complement is an important regulator of adaptive immune responses. Murine studies suggest that complement modulates helper T-cell differentiation, and Th1 responses in particular are impaired in the absence of functional complement. Here, we have studied humora

  4. Fluorescent image tracking velocimeter

    Science.gov (United States)

    Shaffer, Franklin D.

    1994-01-01

    A multiple-exposure fluorescent image tracking velocimeter (FITV) detects and measures the motion (trajectory, direction and velocity) of small particles close to light scattering surfaces. The small particles may follow the motion of a carrier medium such as a liquid, gas or multi-phase mixture, allowing the motion of the carrier medium to be observed, measured and recorded. The main components of the FITV include: (1) fluorescent particles; (2) a pulsed fluorescent excitation laser source; (3) an imaging camera; and (4) an image analyzer. FITV uses fluorescing particles excited by visible laser light to enhance particle image detectability near light scattering surfaces. The excitation laser light is filtered out before reaching the imaging camera allowing the fluoresced wavelengths emitted by the particles to be detected and recorded by the camera. FITV employs multiple exposures of a single camera image by pulsing the excitation laser light for producing a series of images of each particle along its trajectory. The time-lapsed image may be used to determine trajectory and velocity and the exposures may be coded to derive directional information.

  5. Complement-Opsonized HIV-1 Overcomes Restriction in Dendritic Cells.

    Directory of Open Access Journals (Sweden)

    Wilfried Posch

    2015-06-01

    Full Text Available DCs express intrinsic cellular defense mechanisms to specifically inhibit HIV-1 replication. Thus, DCs are productively infected only at very low levels with HIV-1, and this non-permissiveness of DCs is suggested to go along with viral evasion. We now illustrate that complement-opsonized HIV-1 (HIV-C efficiently bypasses SAMHD1 restriction and productively infects DCs including BDCA-1 DCs. Efficient DC infection by HIV-C was also observed using single-cycle HIV-C, and correlated with a remarkable elevated SAMHD1 T592 phosphorylation but not SAMHD1 degradation. If SAMHD1 phosphorylation was blocked using a CDK2-inhibitor HIV-C-induced DC infection was also significantly abrogated. Additionally, we found a higher maturation and co-stimulatory potential, aberrant type I interferon expression and signaling as well as a stronger induction of cellular immune responses in HIV-C-treated DCs. Collectively, our data highlight a novel protective mechanism mediated by complement opsonization of HIV to effectively promote DC immune functions, which might be in the future exploited to tackle HIV infection.

  6. A Preliminary Genetic Analysis of Complement 3 Gene and Schizophrenia.

    Directory of Open Access Journals (Sweden)

    Jianliang Ni

    Full Text Available Complement pathway activation was found to occur frequently in schizophrenia, and complement 3 (C3 plays a major role in this process. Previous studies have provided evidence for the possible role of C3 in the development of schizophrenia. In this study, we hypothesized that the gene encoding C3 (C3 may confer susceptibility to schizophrenia in Han Chinese. We analyzed 7 common single nucleotide polymorphisms (SNPs of C3 in 647 schizophrenia patients and 687 healthy controls. Peripheral C3 mRNA expression level was measured in 23 drug-naïve patients with schizophrenia and 24 controls. Two SNPs (rs1047286 and rs2250656 that deviated from Hardy-Weinberg equilibrium were excluded for further analysis. Among the remaining 5 SNPs, there was no significant difference in allele and genotype frequencies between the patient and control groups. Logistic regression analysis showed no significant SNP-gender interaction in either dominant model or recessive model. There was no significant difference in the level of peripheral C3 expression between the drug-naïve schizophrenia patients and healthy controls. In conclusion, the results of this study do not support C3 as a major genetic susceptibility factor in schizophrenia. Other factors in AP may have critical roles in schizophrenia and be worthy of further investigation.

  7. Dual modulating functions of thrombomodulin in the alternative complement pathway.

    Science.gov (United States)

    Tateishi, Koichiro; Imaoka, Mio; Matsushita, Misao

    2016-07-19

    Thrombomodulin (TM) is a transmembrane protein expressed on vascular endothelial cells. TM has anticoagulant and anti-inflammatory properties. It has recently been reported that TM modulates complement, an immune effector system that destroys pathogens and is also involved in inflammation. TM was demonstrated to enhance the degradation of C3b into iC3b by factor I and factor H, indicating that its role is in negative regulation in the alternative pathway of the complement system. In this study, we examined the effects of recombinant human soluble TM protein composed of the extracellular domains (rTM) on the alternative pathway. The degradation of C3b into iC3b by factor I and factor H was enhanced by rTM as assessed by SDS-PAGE, confirming the previous observation. We also found that rTM enhances the cleavage of C3 into C3b as a result of activation of the alternative pathway. These results indicate that TM has both activating and inactivating functions in the alternative pathway. PMID:27210597

  8. Fluorescence uranium determination

    International Nuclear Information System (INIS)

    An equipment for analysis of uranium by fluorescence was developed in order to determine it at such a low concentration that it can not be determined by the most sensible analytical methods. this new fluorimeter was adapted to measure the fluorescence emitted by the phosphorus sodium fluoride-sodium carbonate-potasium carbonate-uranyl, being excited by ultraviolet light of 3,650 A the intensity of the light emitted was measure with a photomultiplicator RCA 5819 and the adequate electronic equipment. (Author) 19 refs

  9. Nanosecond fluorescence spectroscopy

    International Nuclear Information System (INIS)

    This article is a summary of a short course lecture given in conjunction with the 1984 Nuclear Science Symposium. Measuring systems for nanosecond fluorescence spectroscopy using single-photon counting techniques are presented. These involve systems based on relaxation-type spark gap light pulser and synchronously pumped mode-locked dye lasers. Furthermore, typical characteristics and optimization of operating conditions of the critical components responsible for the system time resolution are discussed. A short comparison of the most important deconvolution methods for numerical analysis of experimental data is given particularly with respect to the signal-to-noise ratio of the fluorescence signal. 22 refs., 8 figs

  10. Fluorescence activated cell sorting.

    Science.gov (United States)

    Bonner, W. A.; Hulett, H. R.; Sweet, R. G.; Herzenberg, L. A.

    1972-01-01

    An instrument has been developed for sorting biological cells. The cells are rendered differentially fluorescent and incorporated into a small liquid stream illuminated by a laser beam. The cells pass sequentially through the beam, and fluorescent light from the cells gives rise to electrical signals. The stream is broken into a series of uniform size drops downstream of the laser. The cell signals are used to give appropriate electrostatic charges to drops containing the cells. The drops then pass between two charged plates and are deflected to appropriate containers. The system has proved capable of providing fractions containing large numbers of viable cells highly enriched in a particular functional type.

  11. Inefficient complement system clearance of Trypanosoma cruzi metacyclic trypomastigotes enables resistant strains to invade eukaryotic cells.

    Directory of Open Access Journals (Sweden)

    Igor Cestari

    Full Text Available The complement system is the main arm of the vertebrate innate immune system against pathogen infection. For the protozoan Trypanosoma cruzi, the causative agent of Chagas disease, subverting the complement system and invading the host cells is crucial to succeed in infection. However, little attention has focused on whether the complement system can effectively control T. cruzi infection. To address this question, we decided to analyse: 1 which complement pathways are activated by T. cruzi using strains isolated from different hosts, 2 the capacity of these strains to resist the complement-mediated killing at nearly physiological conditions, and 3 whether the complement system could limit or control T. cruzi invasion of eukaryotic cells. The complement activating molecules C1q, C3, mannan-binding lectin and ficolins bound to all strains analysed; however, C3b and C4b deposition assays revealed that T. cruzi activates mainly the lectin and alternative complement pathways in non-immune human serum. Strikingly, we detected that metacyclic trypomastigotes of some T. cruzi strains were highly susceptible to complement-mediated killing in non-immune serum, while other strains were resistant. Furthermore, the rate of parasite invasion in eukaryotic cells was decreased by non-immune serum. Altogether, these results establish that the complement system recognizes T. cruzi metacyclic trypomastigotes, resulting in killing of susceptible strains. The complement system, therefore, acts as a physiological barrier which resistant strains have to evade for successful host infection.

  12. Oversulfated chondroitin sulfate inhibits the complement classical pathway by potentiating C1 inhibitor.

    Science.gov (United States)

    Zhou, Zhao-Hua; Rajabi, Mohsen; Chen, Trina; Karnaukhova, Elena; Kozlowski, Steven

    2012-01-01

    Oversulfated chondroitin sulfate (OSCS) has become the subject of multidisciplinary investigation as a non-traditional contaminant in the heparin therapeutic preparations that were linked to severe adverse events. In this study, it was found that OSCS inhibited complement fixation on bacteria and bacterial lysis mediated by the complement classical pathway. The inhibition of complement by OSCS is not due to interference with antibody/antigen interaction or due to consumption of C3 associated with FXII-dependent contact system activation. However, OSCS complement inhibition is dependent on C1 inhibitor (C1inh) since the depletion of C1inh from either normal or FXII-deficient complement plasma prevents OSCS inhibition of complement activity. Surface plasmon resonance measurements revealed that immobilized C1inhibitor bound greater than 5-fold more C1s in the presence of OSCS than in presence of heparin. Although heparin can also inhibit complement, OSCS and OSCS contaminated heparin are more potent inhibitors of complement. Furthermore, polysulfated glycosaminoglycan (PSGAG), an anti-inflammatory veterinary medicine with a similar structure to OSCS, also inhibited complement in the plasma of dogs and farm animals. This study provides a new insight that in addition to the FXII-dependent activation of contact system, oversulfated and polysulfated chondroitin-sulfate can inhibit complement activity by potentiating the classical complement pathway regulator C1inh. This effect on C1inh may play a role in inhibiting inflammation as well as impacting bacterial clearance. PMID:23077587

  13. Oversulfated chondroitin sulfate inhibits the complement classical pathway by potentiating C1 inhibitor.

    Directory of Open Access Journals (Sweden)

    Zhao-Hua Zhou

    Full Text Available Oversulfated chondroitin sulfate (OSCS has become the subject of multidisciplinary investigation as a non-traditional contaminant in the heparin therapeutic preparations that were linked to severe adverse events. In this study, it was found that OSCS inhibited complement fixation on bacteria and bacterial lysis mediated by the complement classical pathway. The inhibition of complement by OSCS is not due to interference with antibody/antigen interaction or due to consumption of C3 associated with FXII-dependent contact system activation. However, OSCS complement inhibition is dependent on C1 inhibitor (C1inh since the depletion of C1inh from either normal or FXII-deficient complement plasma prevents OSCS inhibition of complement activity. Surface plasmon resonance measurements revealed that immobilized C1inhibitor bound greater than 5-fold more C1s in the presence of OSCS than in presence of heparin. Although heparin can also inhibit complement, OSCS and OSCS contaminated heparin are more potent inhibitors of complement. Furthermore, polysulfated glycosaminoglycan (PSGAG, an anti-inflammatory veterinary medicine with a similar structure to OSCS, also inhibited complement in the plasma of dogs and farm animals. This study provides a new insight that in addition to the FXII-dependent activation of contact system, oversulfated and polysulfated chondroitin-sulfate can inhibit complement activity by potentiating the classical complement pathway regulator C1inh. This effect on C1inh may play a role in inhibiting inflammation as well as impacting bacterial clearance.

  14. Structural insight into the recognition of complement C3 activation products by integrin receptors

    DEFF Research Database (Denmark)

    Bajic, Goran

    2015-01-01

    associated with microbes and apoptotic or necrotic cells. Complement not only protects against pathogens but also maintains body homeostasis. Activation of complement leads to cleavage of the complement proteins C4, C3 and C5, and their fragments have effector functions through binding to pathogen surfaces...... small fragment C3a called anaphylatoxin. Complement leads to opsonization as the proteolytic fragment C3b becomes covalently linked to the activator surface through a reactive thioester. Self-surfaces are protected by complement regulators, whereas complement activation vividly amplifies on pathogens....... An important outcome of the regulators is the degradation of C3b to iC3b. Phagocytic receptor αMβ2 integrin (also called CR3, CD11b/CD18, or Mac-1) on leukocytes engages the opsonized activator subsequently to C3b cleavage into iC3b. Apoptotic cells activate complement leading to iC3b deposition and...

  15. Homogeneous detection of concanavalin A using pyrene-conjugated maltose assembled graphene based on fluorescence resonance energy transfer.

    Science.gov (United States)

    Chen, Qiushui; Wei, Weili; Lin, Jin-Ming

    2011-07-15

    In this work, we proposed a novel biosensor to homogeneously detect concanavalin A (ConA) using pyrene-conjugated maltose assembled graphene based on fluorescence resonance energy transfer (FRET). Maltose-grafted-aminopyrene (Mal-Apy) was synthesized and characterized by mass spectra, UV-vis and fluorescence spectra. The Mal-Apy was further employed for fluorescence switch and ConA recognition. When Mal-Apy was self-assembled on the surface of graphene by means of π-stacking interaction, its fluorescence was adequately quenched because the graphene acted as a "nanoquencher" of the pyrene rings due to FRET. As a result, in the presence of ConA, competitive binding of ConA with glucose destroyed the π-stacking interaction between the pyrene and graphene, thereby causing the fluorescence recovery. This method was demonstrated the selective sensing of ConA, and the linear range is 2.0 × 10⁻² to 1.0 μM with the linear equation y=1.029x + 0.284 (R = 0.996). The limit of detection for ConA was low to 0.8 nM, and the detection of ConA could be performed in 5 min, indicating that this method could be used for fast, sensitive, and selective sensing of ConA. Such data suggests that the graphene FRET platform is a great potential application for protein-carbohydrate studies, and would be widely applied in drug screening, bimolecular recognition and disease diagnosis. PMID:21621405

  16. Graphs cospectral with a friendship graph or its complement

    Directory of Open Access Journals (Sweden)

    Alireza Abdollahi

    2013-12-01

    Full Text Available Let $n$ be any positive integer and let $F_n$ be the friendship (or Dutch windmill graph with $2n+1$ vertices and $3n$ edges. Here we study graphs with the same adjacency spectrum as the $F_n$. Two graphs are called cospectral if the eigenvalues multiset of their adjacency matrices are the same. Let $G$ be a graph cospectral with $F_n$. Here we prove that if $G$ has no cycle of length $4$ or $5$, then $Gcong F_n$. Moreover if $G$ is connected and planar then $Gcong F_n$.All but one of connected components of $G$ are isomorphic to $K_2$.The complement $overline{F_n}$ of the friendship graph is determined by its adjacency eigenvalues, that is, if $overline{F_n}$ is cospectral with a graph $H$, then $Hcong overline{F_n}$.

  17. Complement component 3: a new paradigm in tuberculosis vaccine.

    Science.gov (United States)

    De La Fuente, José; Gortázar, Christian; Juste, Ramón

    2016-01-01

    Vaccines are critical for the control of tuberculosis (TB) affecting humans and animals worldwide. First-generation vaccines protect from active TB but new vaccines are required to protect against pulmonary disease and infection. Recent advances in post-genomics technologies have allowed the characterization of host-pathogen interactions to discover new protective antigens and mechanisms to develop more effective vaccines against TB. Studies in the wild boar model resulted in the identification of complement component 3 (C3) as a natural correlate of protection against TB. Oral immunization with heat-inactivated mycobacteria protected wild boar against TB and showed that C3 plays a central role in protection. These results point at C3 as a target to develop novel vaccine formulations for more effective protection against TB in humans and animals. PMID:26605515

  18. Complement levels in acute infectious hepatitis and serum hepatitis

    Science.gov (United States)

    Kosmidis, J. C.; Leader-Williams, Lesley K.

    1972-01-01

    The level of the third component of complement was measured in serial specimens of serum taken from thirty-one patients with acute viral hepatitis. Fourteen of the thirty-one patients were positive for the hepatitis-associated antigen. A characteristic fluctuation was observed in twenty-nine of the thirty-one patients. This consisted of an initial fall of the level of C3, followed by an increase to a higher than normal level and then a gradual return to normal. No difference was observed between the patients who were positive and those who were negative for the hepatitis-associated antigen. These results support the view that immune complexes play a significant role in the pathogenesis of acute viral hepatitis. PMID:4624985

  19. Complement monitoring of Pluronic 127 gel and micelles

    DEFF Research Database (Denmark)

    Hamad, Islam; Hunter, A Christy; Moghimi, Seyed Moien

    2013-01-01

    Poloxamer 407 is a non-ionic polyethylene oxide (PEO)/polypropylene oxide (PPO) block copolymer, which exhibits reversible thermogelation properties. Poloxamer gel has attracted many applications for controlled release of therapeutic agents as well as in surgical interventions such as controlled...... above its cmc) with human LDL, which could have played a significant role in regulating complement activation. These observations are in line with the suggested modulatory role of lipoproteins in host defence and inflammatory processes. A better understanding of block copolymer interaction with...... lipoproteins/apolipoproteins could improve the immune safety of surgical and therapeutic interventions requiring PEO/PPO block copolymers and may provide new insights for combinatorial design of multifunctional copolymers....

  20. Functional assay of the alternative complement pathway of rat serum

    International Nuclear Information System (INIS)

    Two functional assays of the alternative pathway of complement activation in rat serum were developed. In the first assay, conditions were established for titration of alternative pathway activity by use of the 50% hemolytic end-point of rabbit red blood cells (RaRBC) in serum treated with ethyleneglycol-bis-(beta-aminoethyl ether)-N, N'-tetraacetic acid (EGTA). The second assay of alternative pathway activity was based on the opsonization of heat-killed radiolabeled pneumococci of serotype 25 (Pn25). Opsonization of Pn25 was shown to proceed entirely via the alternative pathway in rat serum. There was excellent correlation between the results obtained with the RaRBC lysis test and those obtained with the opsonization test. Because of its technical simplicity, the RaRBC lysis test appeared to be the single most useful test of alternative pathway activity in rat serum. (Auth.)

  1. Complement alternative pathway activation in human nonalcoholic steatohepatitis.

    Directory of Open Access Journals (Sweden)

    Filip M Segers

    Full Text Available The innate immune system plays a major role in the pathogenesis of nonalcoholic steatohepatitis (NASH. Recently we reported complement activation in human NASH. However, it remained unclear whether the alternative pathway of complement, which amplifies C3 activation and which is frequently associated with pathological complement activation leading to disease, was involved. Here, alternative pathway components were investigated in liver biopsies of obese subjects with healthy livers (n = 10 or with NASH (n = 12 using quantitative PCR, Western blotting, and immunofluorescence staining. Properdin accumulated in areas where neutrophils surrounded steatotic hepatocytes, and colocalized with the C3 activation product C3c. C3 activation status as expressed by the C3c/native C3 ratio was 2.6-fold higher (p<0.01 in subjects with NASH despite reduced native C3 concentrations (0.94±0.12 vs. 0.57±0.09; p<0.01. Hepatic properdin levels positively correlated with levels of C3c (rs = 0.69; p<0.05 and C3c/C3 activation ratio (rs = 0.59; p<0.05. C3c, C3 activation status (C3c/C3 ratio and properdin levels increased with higher lobular inflammation scores as determined according to the Kleiner classification (C3c: p<0.01, C3c/C3 ratio: p<0.05, properdin: p<0.05. Hepatic mRNA expression of factor B and factor D did not differ between subjects with healthy livers and subjects with NASH (factor B: 1.00±0.19 vs. 0.71±0.07, p = 0.26; factor D: 1.00±0.21 vs. 0.66±0.14, p = 0.29;. Hepatic mRNA and protein levels of Decay Accelerating Factor tended to be increased in subjects with NASH (mRNA: 1.00±0.14 vs. 2.37±0.72; p = 0.22; protein: 0.51±0.11 vs. 1.97±0.67; p = 0.28. In contrast, factor H mRNA was downregulated in patients with NASH (1.00±0.09 vs. 0.71±0.06; p<0.05 and a similar trend was observed with hepatic protein levels (1.12±0.16 vs. 0.78±0.07; p = 0.08. Collectively, these data suggest a role for alternative

  2. Ultraviolet fluorescence monitor

    Energy Technology Data Exchange (ETDEWEB)

    Hargis, P.J. Jr.; Preppernau, B.L.; Aragon, B.P. [Sandia National Labs., Albuquerque, NM (United States). Laser, Optics and Remote Sensing Dept.

    1997-05-01

    A multispectral ultraviolet (UV) fluorescence imaging fluorometer and a pulsed molecular beam laser fluorometer were developed to detect volatile organic compounds of interest in environmental monitoring and drug interdiction applications. The UV fluorescence imaging fluorometer is a relatively simple instrument which uses multiple excitation wavelengths to measure the excitation/emission matrix for irradiated samples. Detection limits in the high part-per-million to low part-per-million range were measured for a number of volatile organic vapors in the atmosphere. Detection limits in the low part-per-million range were obtained using cryogenic cooling to pre-concentrate unknown samples before introducing them into the imaging fluorometer. A multivariate analysis algorithm was developed to analyze the excitation/emission matrix and used to determine the relative concentrations of species in computer synthesized mixtures containing up to five organic compounds. Analysis results demonstrated the utility of multispectral UV fluorescence in analytical measurements. A transportable UV fluorescence imaging fluorometer was used in two field tests. Field test results demonstrated that detection limits in the part-per-billion range were needed to reliably identify volatile organic compounds in realistic field test measurements. The molecular beam laser fluorometer, a more complex instrument with detection limits in the part-per-billion to part-per-trillion range, was therefore developed to satisfy detection sensitivity requirements for field test measurements. High-resolution spectroscopic measurements made with the molecular beam laser fluorometer demonstrated its utility in identifying volatile organic compounds in the atmosphere.

  3. Yeast fluorescence microscopy

    Czech Academy of Sciences Publication Activity Database

    Hašek, Jiří

    New Jersey : Humana Press, 2005, s. 85-96. ISBN 1-59259-958-3 R&D Projects: GA AV ČR IAA5020102; GA ČR GA204/02/1424 Institutional research plan: CEZ:AV0Z50200510 Keywords : yeast * fluorescence microscopy * immunofluorescence Subject RIV: EE - Microbiology, Virology

  4. Statistical filtering in fluorescence microscopy and fluorescence correlation spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Macháň, Radek; Kapusta, Peter; Hof, Martin

    2014-01-01

    Roč. 406, č. 20 (2014), s. 4797-4813. ISSN 1618-2642 R&D Projects: GA ČR GBP208/12/G016 Institutional support: RVO:61388955 Keywords : Filtered fluorescence correlation spectroscopy * Fluorescence lifetime correlation spectroscopy * Fluorescence spectral correlation spectroscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.436, year: 2014

  5. Green fluorescent protein: A perspective

    OpenAIRE

    Remington, S James

    2011-01-01

    A brief personal perspective is provided for green fluorescent protein (GFP), covering the period 1994–2011. The topics discussed are primarily those in which my research group has made a contribution and include structure and function of the GFP polypeptide, the mechanism of fluorescence emission, excited state protein transfer, the design of ratiometric fluorescent protein biosensors and an overview of the fluorescent proteins derived from coral reef animals. Structure-function relationship...

  6. Structural Basis for the Function of Complement Component C4 within the Classical and Lectin Pathways of Complement

    DEFF Research Database (Denmark)

    Mortensen, Sofia; Kidmose, Rune Thomas; Petersen, Steen Vang;

    2015-01-01

    for removal. Moreover, C4b provides a platform for assembly of the proteolytically active convertases that mediate downstream complement activation by cleavage of C3 and C5. In this article, we present the crystal and solution structures of the 195-kDa C4b. Our results provide the molecular details of...... the rearrangement accompanying C4 cleavage and suggest intramolecular flexibility of C4b. The conformations of C4b and its paralogue C3b are shown to be remarkably conserved, suggesting that the convertases from the classical and alternative pathways are likely to share their overall architecture and...... mode of substrate recognition. We propose an overall molecular model for the classical pathway C5 convertase in complex with C5, suggesting that C3b increases the affinity for the substrate by inducing conformational changes in C4b rather than a direct interaction with C5. C4b-specific features...

  7. Synthesis and Fluorescence Spectra of Triazolylcoumarin Fluorescent Dyes

    Institute of Scientific and Technical Information of China (English)

    PENG Xian-fu; LI Hong-qi

    2009-01-01

    Much attention is devoted to fluorescent dyes especially those with potential in versatile applications. Reactions under "click" conditions between nonfluorescent 3 - azidocoumarins and terminal alkynes produced 3 -(1, 2, 3- triazol- 1 - yl)cournarins, a novel type of fluorescent dyes with intense fluorescence. The structures of the new coumarins were characterized by 1H NMR, MS, and IR spectra. Fluorescence spectra measurement demonstrated excellent fluorescence performance of the triazolylcoumarins and this click reaction is a promising candidate for bioconjugation and bioimaging applications since both azide and alkynes are quite inert to biological systems.

  8. Fluorescence nanoscopy. Methods and applications

    OpenAIRE

    Requejo-Isidro, Jose

    2013-01-01

    Fluorescence nanoscopy refers to the experimental techniques and analytical methods used for fluorescence imaging at a resolution higher than conventional, diffraction-limited, microscopy. This review explains the concepts behind fluorescence nanoscopy and focuses on the latest and promising developments in acquisition techniques, labelling strategies to obtain highly detailed super-resolved images and in the quantitative methods to extract meaningful information from them.

  9. Fluorescence spectroscopy of dental calculus

    International Nuclear Information System (INIS)

    The aim of the present study was to investigate the fluorescence properties of dental calculus in comparison with the properties of adjacent unaffected tooth structure using both lasers and LEDs in the UV-visible range for fluorescence excitation. The influence of calculus color on the informative signal is demonstrated. The optimal spectral bands of excitation and registration of the fluorescence are determined

  10. Cleavage of Complement C3b to iC3b on the Surface of Staphylococcus aureus Is Mediated by Serum Complement Factor I

    OpenAIRE

    Cunnion, K. M.; Hair, P. S.; Buescher, E. S.

    2004-01-01

    Complement-mediated opsonization of Staphylococcus aureus bearing the dominant capsule serotypes, serotypes 5 and 8, remains incompletely understood. We have previously shown that complement plays a vital role in the efficient phagocytosis of a serotype 5 S. aureus strain and that the opsonic fragments of the central complement protein C3, C3b and iC3b, were present on the bacterial surface after incubation in human serum. In the present studies, C3b and iC3b were found on several serotype 5 ...

  11. Magnetic fluorescent lamp

    Science.gov (United States)

    Berman, S.M.; Richardson R.W.

    1983-12-29

    The radiant emission of a mercury-argon discharge in a fluorescent lamp assembly is enhanced by providing means for establishing a magnetic field with lines of force along the path of electron flow through the bulb of the lamp assembly, to provide Zeeman splitting of the ultraviolet spectral line. Optimum results are obtained when the magnetic field strength causes a Zeeman splitting of approximately 1.7 times the thermal line width.

  12. Plasmonic fluorescent quantum dots

    OpenAIRE

    Jin, Yongdong; Gao, Xiaohu

    2009-01-01

    Combining multiple discrete components into a single multifunctional nanoparticle could be useful in a variety of applications. Retaining the unique optical and electrical properties of each component after nanoscale integration is, however, a long-standing problem1,2. It is particularly difficult when trying to combine fluorophores such as semiconductor quantum dots with plasmonic materials such as gold, because gold and other metals can quench the fluorescence3,4. So far, the combination of...

  13. Vaccinia complement control protein: Multi-functional protein and a potential wonder drug

    Indian Academy of Sciences (India)

    Purushottam Jha; Girish J Kotwal

    2003-04-01

    Vaccinia virus complement control protein (VCP) was one of the first viral molecules demonstrated to have a role in blocking complement and hence in the evasion of host defense. Structurally it is very similar to the human C4b-BP and the other members of complement control protein. Functionally it is most similar to the CR1 protein. VCP blocks both major pathways of complement activation. The crystal structure of VCP was determined a little over a year ago and it is the only known structure of an intact and complete complement control protein. In addition to binding complement, VCP also binds to heparin. These two binding abilities can take place simultaneously and contribute to its many function and to its potential use in several inflammatory diseases, e.g. Alzheimer’s disease (AD), CNS injury, xenotransplantation, etc. making it a truly fascinating molecule and potential drug.

  14. Fluorescent nanodiamond for biomedicine

    International Nuclear Information System (INIS)

    NV centers in diamond have gained strong interest as a novel tool for quantum information processing, quantum computing and quantum photonics. These applications are based on fluorescent and spin properties of NV-centres. However, in some conditions NV- can lose an electron and turn to NV0. The occupation of NV0 and NV- charge states depend on the position of their ground states with respect to the Fermi level and the mechanism of the charge transfer. Interestingly, that the charge switch has important implications on applications of fluorescent nanodiamond (fND) to nano-biology and nano-medicine. fND can be used for bio-marking and bio-tracking but also for the monitoring of targeted delivery to the cells. In this presentation we review the current state-of-the art for using fND particles for fluorescent bio imaging in cells and discuss the charge transfer and its luminescence stability by using ultra high sensitive spectroscopy methods to study the NV0 and NV- state occupation. (author)

  15. Protein- protein interaction detection system using fluorescent protein microdomains

    Science.gov (United States)

    Waldo, Geoffrey S.; Cabantous, Stephanie

    2010-02-23

    The invention provides a protein labeling and interaction detection system based on engineered fragments of fluorescent and chromophoric proteins that require fused interacting polypeptides to drive the association of the fragments, and further are soluble and stable, and do not change the solubility of polypeptides to which they are fused. In one embodiment, a test protein X is fused to a sixteen amino acid fragment of GFP (.beta.-strand 10, amino acids 198-214), engineered to not perturb fusion protein solubility. A second test protein Y is fused to a sixteen amino acid fragment of GFP (.beta.-strand 11, amino acids 215-230), engineered to not perturb fusion protein solubility. When X and Y interact, they bring the GFP strands into proximity, and are detected by complementation with a third GFP fragment consisting of GFP amino acids 1-198 (strands 1-9). When GFP strands 10 and 11 are held together by interaction of protein X and Y, they spontaneous association with GFP strands 1-9, resulting in structural complementation, folding, and concomitant GFP fluorescence.

  16. VERSATILITY OF THE COMPLEMENT SYSTEM IN NEUROINFLAMMATION, NEURODEGENERATION AND BRAIN HOMEOSTASIS

    Directory of Open Access Journals (Sweden)

    Franca Orsini

    2014-11-01

    Full Text Available The immune response after brain injury is highly complex and involves both local and systemic events at the cellular and molecular level. It is associated to a dramatic over-activation of enzyme systems, the expression of proinflammatory genes and the activation/recruitment of immune cells. The complement system represents a powerful component of the innate immunity and is highly involved in the inflammatory response. Complement components are synthesized predominantly by the liver and circulate in the bloodstream primed for activation. Moreover, brain cells can produce complement proteins and receptors. After acute brain injury, the rapid and uncontrolled activation of the complement leads to massive release of inflammatory anaphylatoxins, recruitment of cells to the injury site, phagocytosis and induction of blood brain barrier damage. Brain endothelial cells are particularly susceptible to complement-mediated effects, since they are exposed to both circulating and locally synthesized complement proteins. Conversely, during neurodegenerative disorders, complement factors play distinct roles depending on the stage and degree of neuropathology. In addition to the deleterious role of the complement, increasing evidence suggest that it may also play a role in normal nervous system development (wiring the brain and adulthood (either maintaining brain homeostasis or supporting regeneration after brain injury. This article represents a compendium of the current knowledge on the complement role in the brain, prompting a novel view that complement activation can result in either protective or detrimental effects in brain conditions that depend exquisitely on the nature, the timing and the degree of the stimuli that induce its activation. A deeper understanding of the acute, subacute and chronic consequences of complement activation is needed and may lead to new therapeutic strategies, including the ability of targeting selective step in the complement

  17. Complement system activation contributes to the ependymal damage induced by microbial neuraminidase

    OpenAIRE

    Granados-Durán, Pablo; López-Ávalos, María Dolores; Hughes, Timothy R.; Johnson, Krista; Morgan, B. Paul; Tamburini, Paul P.; Fernández-Llebrez, Pedro; Grondona, Jesús M.

    2016-01-01

    Background In the rat brain, a single intracerebroventricular injection of neuraminidase from Clostridium perfringens induces ependymal detachment and death. This injury occurs before the infiltration of inflammatory blood cells; some reports implicate the complement system as a cause of these injuries. Here, we set out to test the role of complement. Methods The assembly of the complement membrane attack complex on the ependymal epithelium of rats injected with neuraminidase was analyzed by ...

  18. Association of the porcine C3 gene with haemolytic complement activity in the pig

    OpenAIRE

    Mekchay Supamit; Ponsuksili Siriluck; Schellander Karl; Wimmers Klaus

    2003-01-01

    Abstract The complement component C3 plays an essential role in the activated complement system, which is involved in phagocytosis, inflammation and immunoregulation to destroy infectious microorganisms. The C3 molecule has more implications in the general defence mechanisms. In this study, the porcine C3 cDNA sequences including 5'- and 3'- flanking regions were determined and the polymorphisms in this gene were identified to carry out an association analysis between C3 and complement activi...

  19. Capsule Production and Growth Phase Influence Binding of Complement to Staphylococcus aureus

    OpenAIRE

    Cunnion, K. M.; Lee, J. C.; Frank, M M

    2001-01-01

    Complement-mediated opsonization of bacteria by C3 binding is an important component of the host innate immune system. Little information is available concerning the interaction between complement proteins and capsule type 5 and 8 Staphylococcus aureus strains, even though these isolates are responsible for ∼70% of human staphylococcal infections. To investigate the importance of an intact complement pathway in an experimental staphylococcal infection, control and C3-depleted mice were challe...

  20. Lack of hidden complement fixing IgM rheumatoid factor in adult seronegative rheumatoid arthritis.

    OpenAIRE

    Robbins, D L; Moore, T L

    1980-01-01

    IgM rheumatoid factors capable of complement fixation and activation are commonly present in the sera of adults with rheumatoid arthritis. Hidden complement fixing IgM rheumatoid factor has been demonstrated in the majority of patients with juvenile RA and hidden agglutinating IgM rheumatoid factors have been demonstrated in the serum of adults with seronegative rheumatoid arthritis. We studied 27 adults with seronegative rheumatoid arthritis and were unable to demonstrate hidden complement f...

  1. Synergistic actions of complement and lysozyme in clearance of Escherichia coli from amphioxus Branchiostoma belcheri

    Institute of Scientific and Technical Information of China (English)

    Guangfeng Wang; Shicui Zhang; Zhimeng Zhuang; Zhiping Wang

    2009-01-01

    Amphioxus appears to lack free circulating blood cells. How it clears invading pathogens from its body remains unknown to date. We demonstrate here that amphioxus Branchiostoma belcheri is capable of efficiently eliminating the invading bacterium Escherichia coil from its humorai fluid, and the complement and lysozyme are both involved in the elimination of the invading pathogen. Both the com-plement and lysozyme act in concert against the invading bacterium, but the complement appears to play a more dominant role than the lysozyme.

  2. New insights into the reaction of Schistosoma mansoni cercaria to the human complement system

    OpenAIRE

    Da'dara, Akram A.; KRAUTZ-PETERSON, GREICE

    2014-01-01

    Schistosomes are parasitic worms that have a complex life cycle. The larval stage cercaria, infectious to mammals, is described as highly susceptible to the complement system, largely due to the glycocalyx that covers the cercarial membrane. In an attempt to have a more complete understanding of cercaria reaction to the complement system, three different approaches were used. Live cercariae exposed to normal human serum (NHS) as source of complement factors were assessed for: i) Membrane Atta...

  3. The complement cascade as a mediator of tissue growth and regeneration

    OpenAIRE

    Rutkowski, Martin J.; Sughrue, Michael E.; Kane, Ari J.; Ahn, Brian J.; Fang, Shanna; Parsa, Andrew T.

    2010-01-01

    Recent evidence has demonstrated that the complement cascade is involved in a variety of physiologic and pathophysiologic processes in addition to its role as an immune effector. Research in a variety of organ systems has shown that complement proteins are direct participants in maintenance of cellular turnover, healing, proliferation and regeneration. As a physiologic housekeeper, complement proteins maintain tissue integrity in the absence of inflammation by disposing of cellular debris and...

  4. C-Reactive Protein and Complement Are Important Mediators of Tissue Damage in Acute Myocardial Infarction

    OpenAIRE

    Griselli, M; Herbert, J.; Hutchinson, W. L.; Taylor, K. M.; Sohail, M; Krausz, T.; Pepys, M. B.

    1999-01-01

    Myocardial infarction in humans provokes an acute phase response, and C-reactive protein (CRP), the classical acute phase plasma protein, is deposited together with complement within the infarct. The peak plasma CRP value is strongly associated with postinfarct morbidity and mortality. Human CRP binds to damaged cells and activates complement, but rat CRP does not activate complement. Here we show that injection of human CRP into rats after ligation of the coronary artery reproducibly enhance...

  5. Complement-related Innovations: From the immunology laboratories to biotechnology companies

    OpenAIRE

    Kheir Eddine Kerboua; Bey Baba-Hamed; Mourad Aribi

    2014-01-01

    Increased knowledge about the involvement of complement network in physiology, pathology and homeostasis,the development of high qualified research teams in structural and analytical techniques, and the promising experiences of Eculizumab and Mirococept in human medicine have resulted in thousands of creative approaches on Complement-related Innovations (CRI) in various immunological applications. This paperexposes the biotechnological attractiveness of the over fifty complement proteins in t...

  6. Closed essential surfaces in the complements of large volume Berge knots

    OpenAIRE

    Baker, Kenneth L.

    2005-01-01

    We construct an algorithm that lists all closed essential surfaces in the complement of a knot that lies on the fiber of a trefoil or figure eight knot. Such knots are Berge knots and hence admit lens space surgeries. Furthermore they may have arbitrarily large hyperbolic volume. Using this algorithm we concoct large volume Berge knots of two flavors: those whose complement contains arbitrarily many distinct closed essential surfaces, and those whose complement contains no closed essential su...

  7. Spectrally resolved multidepth fluorescence imaging

    Science.gov (United States)

    Luo, Yuan; Zervantonakis, Ioannis K.; Oh, Se Baek; Kamm, Roger D.; Barbastathis, George

    2011-09-01

    We present a multicolor fluorescence imaging modality to visualize in real-time tissue structures emitting multispectral fluorescent light from different focal depths. Each designated spectrum of fluorescent emission from a specific depth within a volumetric tissue is probed by a depth-spectrum selective holographic grating. The grating for each fluorescent color are multiplexed within a volume hologram, which enables simultaneously obtaining multicolored fluorescent information at different depths within a biological tissue sample. We demonstrate the imaging modality's ability to obtain laser-induced multicolored fluorescence images of a biological sample from different depths without scanning. We also experimentally demonstrate that the imaging modality can be simultaneously operated at both fluorescent and bright field modes to provide complementary information of volumetric tissue structures at different depths in real-time.

  8. Complement receptor 1 and the molecular pathogenesis of malaria

    Directory of Open Access Journals (Sweden)

    Gandhi Monika

    2007-01-01

    Full Text Available Malaria is a pathogenic infection caused by protozoa of the genus plasmodium. It is mainly confined to sub-Saharan Africa, Asia and South America. This disease claims the life of over 1.5 to 2.7 million people per year. Owing to such a high incidence of malarial infections, there is an urgent need for the development of suitable vaccines. For the development of ideal vaccines, it is essential to understand the molecular mechanisms of malarial pathogenesis and the factors that lead to malaria infection. Genetic factors have been proposed to play an important role in malarial pathogenesis. Complement receptor 1 (CR1 is an important host red blood cell protein involved in interaction with malarial parasite. Various polymorphic forms of CR1 have been found to be involved in conferring protection or increasing susceptibility to malaria infections. Low-density allele (L of CR1 gave contradictory results in different set of studies. In addition, Knops polymorphic forms Sl (a + and McC (a have been found to contribute more towards the occurrence of cerebral malaria in malaria endemic regions compared to individuals with Sl (a - / McC (a/b genotype. This article reviews the research currently going on in this area and throws light on as yet unresolved mysteries of the role of CR1 in malarial pathogenesis.

  9. Structural basis of complement membrane attack complex formation

    Science.gov (United States)

    Serna, Marina; Giles, Joanna L.; Morgan, B. Paul; Bubeck, Doryen

    2016-02-01

    In response to complement activation, the membrane attack complex (MAC) assembles from fluid-phase proteins to form pores in lipid bilayers. MAC directly lyses pathogens by a `multi-hit' mechanism; however, sublytic MAC pores on host cells activate signalling pathways. Previous studies have described the structures of individual MAC components and subcomplexes; however, the molecular details of its assembly and mechanism of action remain unresolved. Here we report the electron cryo-microscopy structure of human MAC at subnanometre resolution. Structural analyses define the stoichiometry of the complete pore and identify a network of interaction interfaces that determine its assembly mechanism. MAC adopts a `split-washer' configuration, in contrast to the predicted closed ring observed for perforin and cholesterol-dependent cytolysins. Assembly precursors partially penetrate the lipid bilayer, resulting in an irregular β-barrel pore. Our results demonstrate how differences in symmetric and asymmetric components of the MAC underpin a molecular basis for pore formation and suggest a mechanism of action that extends beyond membrane penetration.

  10. Fluorescence quenching of aromatic hydrocarbons by nitroxide radicals: a mechanismatic study

    Directory of Open Access Journals (Sweden)

    Stephan Landgraf

    1999-01-01

    Full Text Available The fluorescence quenching of phenanthrene (Phen, 9-cyanophenanthrene (CPhen, 9-cyanoanthracene (CA, perylene (Per, 9,10-dicyanoanthracene (DCA, and 9,10-diphenylanthracene (DPA using stable nitroxide radicals as quenchers has been studied by steady state and flash photolysis measurements. Both linearity and deviation from linearity in the Stern-Volmer plots have been observed. The active sphere model was used to discuss the upward curvature of the Stern-Volmer plots in case of Per, DCA, and DPA. The bimolecular quenching rate constant (kq of Phen, CPhen and CA was found to be diffusion controlled while in other cases it is lower than the diffusion limit. On the basis of flash photolysis measurements as well as the overlap between the emission spectra of hydrocarbons and the absorption spectra of radicals, a resonance energy transfer mechanism is taken place in case of Per, DPA, DCA, and CA. For Phen and CPhen where the energy gap between the first excited singlet and the nearest lower triplet state is small, an induced intersystem crossing was suggested. Finally, the quenching process was discussed in terms of the free energy dependence (ΔG of the electron transfer from nitroxide radicals to the excited hydrocarbons.

  11. Complementing xeroderma pigmentosum fibroblasts restore biological activity to UV-damaged DNA

    International Nuclear Information System (INIS)

    UV survival curves of adenovirus 2 using fused complementing xeroderma pigmentosum fibroblast strains as virus hosts showed a component with an inactivation slope identical to that given by normal cells. This component was not observed when the fibroblasts were not fused or when fusions involved strains in the same complementing group. Extrapolation to zero dose indicated that three percent of the viral plaque-forming units had infected cells capable of normal repair; this suggested that three percent of the cells were complementing heterokaryons. Thus, heterokaryons formed from xeroderma pigmentosum fibroblasts belonging to different complementation groups are as capable of restoring biological activity to UV-damaged adenovirus 2 as are normal cells

  12. A review of current knowledge of the complement system and the therapeutic opportunities in inflammatory arthritis.

    Science.gov (United States)

    Mizuno, M

    2006-01-01

    The complement activation system, a key component of the innate immune system, protects the host from microorganisms such as bacteria, and other foreign threats including abnormal cells. However, it is also double-edged in that it can have negative effects in the host; excessive complement activation damages the host and can even kill in anaphylactic shock and septic shock. Regulation of the complement system is a useful strategy to control inflammatory diseases, including inflammatory arthritis. Rheumatoid arthritis is a common inflammatory disease worldwide. Many medicines are developed to control inflammation, including recently developed biological response modifiers such as anti-TNF and IL-6 agents. Nevertheless, in some patients disease remains difficult to control because of complications, side effects and tolerance of medicines. In inflammatory arthritis, including rheumatoid arthritis, there is abundant evidence implicating complement activation in humans and animal models. Therefore, anti-complement agents might be beneficial as part of clinical treatment. However, at present, there are still no applicable agents for therapeutic regulation of excessive complement activation in chronic disease. Novel agents in development might be useful as a strategy to control complement activation. Here I describe recent knowledge of the complement system in inflammatory arthritis, the recent developments in anti-complement agents and their considerable potential for the future. PMID:16787214

  13. Complement: a novel factor in basal and ischemia-induced neurogenesis

    OpenAIRE

    Rahpeymai, Yalda; Hietala, Max Albert; Wilhelmsson, Ulrika; Fotheringham, Andrew; Davies, Ioan; Nilsson, Ann-Katrin; Zwirner, Jörg; Wetsel, Rick A.; Gerard, Craig; Pekny, Milos; Pekna, Marcela

    2006-01-01

    Through its involvement in inflammation, opsonization, and cytolysis, the complement protects against infectious agents. Although most of the complement proteins are synthesized in the central nervous system (CNS), the role of the complement system in the normal or ischemic CNS remains unclear. Here we demonstrate for the first time that neural progenitor cells and immature neurons express receptors for complement fragments C3a and C5a (C3a receptor (C3aR) and C5a receptor). Mice that are def...

  14. The role of complement activation in atherogenesis: the first 40 years.

    Science.gov (United States)

    Vlaicu, Sonia I; Tatomir, Alexandru; Rus, Violeta; Mekala, Armugam P; Mircea, Petru A; Niculescu, Florin; Rus, Horea

    2016-02-01

    The pathogenesis of atherosclerotic inflammation is a multi-step process defined by the interweaving of excess modified lipid particles, monocyte-macrophages populations, and innate immune and adaptive immunity effectors. A part of innate immunity, the complement system, is an important player in the induction and progression of atherosclerosis. The accumulation of either oxidized or enzymatically modified LDL-bound to C-reactive protein or not-prompts complement activation leading to the assembly of the terminal complement C5b-9 complex in the atherosclerotic lesion. The sublytic C5b-9 assembly leads to the activation and proliferation of smooth muscle and endothelial cells, accompanied by the release of various chemotactic, pro-adhesion, and procoagulant cytokines from these cells. Response gene to complement (RGC)-32, an essential effector of the terminal complement complex C5b-9, also affects atherogenesis, propelling vascular smooth muscle cell proliferation and migration, stimulating endothelial proliferation, and promoting vascular lesion formation. A substantial amount of experimental work has suggested a role for the complement system activation during atherosclerotic plaque formation, with the proximal classical complement pathway seemingly having a protective effect and terminal complement contributing to accelerated atherogenesis. All these data suggest that complement plays an important role in atherogenesis. PMID:26091721

  15. Complement receptor expression and activation of the complement cascade on B lymphocytes from patients with systemic lupus erythematosus (SLE)

    DEFF Research Database (Denmark)

    Marquart, H V; Svendsen, A; Rasmussen, J M;

    1995-01-01

    receptors and regulatory proteins on B cells from SLE patients, as well as the deposition of C3 fragments occurring in vivo or after in vitro AP activation. We have confirmed, for a proportion of the patients studied, reduced expression of CR1 and CR2 on B cells, and shown a consistency between low CR2...... expression and reduced in vitro AP activation in the presence of homologous, normal serum. In addition, the B cells, like erythrocytes, bear raised levels of in vivo-deposited C3dg, but not C3b fragments, compared with normal B cells. The erythrocytes from SLE patients were unable to inhibit in vitro AP......It has previously been reported that the expression of the complement receptors, CR1 on erythrocytes and blood leucocytes and CR2 on B cells, is reduced in patients with SLE, and that the reduced expression of CR1 on erythrocytes is related to disease activity. We have earlier demonstrated that...

  16. Investigation of the fluorescence quenching of 2,3-diazabicyclo[2.2.2]oct-2-ene (DBO) by certain substituted uracils

    Energy Technology Data Exchange (ETDEWEB)

    Anbazhagan, V. [School of Chemistry, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu (India); Renganathan, R. [School of Chemistry, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu (India)], E-mail: rrengas@yahoo.com

    2009-04-15

    The fluorescence quenching of 2,3-diazabicyclo[2.2.2]oct-2-ene (DBO) by a series of uracils has been studied in water and acetonitrile solvents using steady-state and time-resolved fluorescence techniques. The steady-state fluorescence quenching technique has been performed in three different pHs (i.e. 4, 8 and 12). The bimolecular quenching rate constant (k{sub q}) increases with increase in pH of uracils. In acidic pH, a pure hydrogen atom abstraction is proposed as the quenching mechanism. This is supported by a pronounced solvent deuterium isotope effect. Electron transfer from the anionic form of uracil to the excited state of DBO is proposed as a mechanism for quenching in basic pH on the basis of highly exergonic thermodynamics obtained from the Rehm-Weller equation. The variation of k{sub q} is explained on the basis of the electronic effect of substitution in uracils as well.

  17. Fluorescence enhancement of N{sub 2}O{sub 2}-type dipyrrin ligand in two step responding to zinc(II) ion

    Energy Technology Data Exchange (ETDEWEB)

    Song, Hyesun; Rajendiran, Senkuttuvan [Department of Bio and Nano Chemistry, College of Natural Sciences, Kookmin University, 861-1 Jeongneung-dong, Seongbuk-gu, Seoul 136-702 (Korea, Republic of); Koo, Eunhae [Bio-IT Convergence Center, Korea Institute of Ceramic Engineering and Technology, Seoul 153-801 (Korea, Republic of); Min, Byoung Koun [Hydrogen Energy Research Center, 39-1 Hawolgek-dong, Seongbuk-gu Seoul 136-791 (Korea, Republic of); Jeong, Soon Kwan [Greenhouse Gas Research Center, Korea Institute of Energy Research, Daejeon 305-343 (Korea, Republic of); Daniel Thangadurai, T., E-mail: danielt@kookmin.ac.kr [Department of Bio and Nano Chemistry, College of Natural Sciences, Kookmin University, 861-1 Jeongneung-dong, Seongbuk-gu, Seoul 136-702 (Korea, Republic of); Yoon, Sungho, E-mail: yoona@kookmin.ac.kr [Department of Bio and Nano Chemistry, College of Natural Sciences, Kookmin University, 861-1 Jeongneung-dong, Seongbuk-gu, Seoul 136-702 (Korea, Republic of)

    2012-11-15

    Fluorescence imaging is well-suited for the live imaging of biological Zn(II), which has no facile spectroscopic or magnetic signature. The successful application of this methodology requires the development of robust Zn(II) imaging agents that display high sensitivity, selectivity and temporal fidelity. In this study, a N{sub 2}O{sub 2}-type dipyrrin based bimolecular zinc(II) complex was produced and shown to have sharper, blue-shifted and more enhanced fluorescence emission. An approximate three-fold fluorescence enhancement was achieved within the micromolar concentration range, which is an important parameter for Zn(II) detection in vivo. The increase in emission intensity was due to the dominant role of aryl-ring rotation in governing the excited state dynamics and fluorescence properties of the dipyrrin dye. Fluorescence titration showed that the ligand complex exhibited very strong zinc(II) binding affinity when compared to that in the binuclear chloro complex. The fluorescence emission changes in the dipyrrin dye to zinc(II) ion could be observed not only using instruments but also by the naked-eye (violet{yields}sky blue). - Graphical abstract: A N{sub 2}O{sub 2}-type dipyrrin (BB2) has been shown to have sharper, blue-shifted and more enhanced fluorescence emission upon treatment of Zn(II) salt with the detection limit (LOD) of ca. 4.2 nM. Fluorescence response of BB2 upon zinc complex formation can be observed by the naked-eye. Highlights: Black-Right-Pointing-Pointer The fluorophore ligand, N{sub 2}O{sub 2}-type dipyrrin (BB2), showed two step responses to zinc(II) ion. Black-Right-Pointing-Pointer Addition of 0.2 equiv. of ZnCl{sub 2} to BB2 immediately increased the fluorescence intensity. Black-Right-Pointing-Pointer Only micromolar concentrations of ZnCl{sub 2} were needed to achieve 3-fold fluorescence enhancement. Black-Right-Pointing-Pointer Fluorescence response of the substituted dipyrrin dye upon zinc complex formation can be observed by the

  18. Complement component C7 deficiency in a Spanish family.

    Science.gov (United States)

    Vázquez-Bermúdez, M F; Barroso, S; Walter, K; Alvarez, A J; Alarcón, A; López-Trascasa, M; Wichmann, I; Aguilar, F; Núñez-Roldán, A; Sánchez, B

    2003-08-01

    Different genetic mutations have been described in complement component C7 deficiency, a molecular defect which is clinically associated with an increased susceptibility to neisserial recurrent infections, although some cases remain asymptomatic. In this work we report the genetic bases of C7 deficiency in one Spanish family. Exon-specific PCR and sequencing revealed a novel point mutation at nucleotide 615 (exon 6) leading to a stop codon (UGG to UGA) in the patient, his mother, and sister. This transversion causes the premature truncation of the C7 protein (W183X). Additionally, we detected a missense mutation at position 1135 (exon 9) located in the first nucleotide of the codon GGG (CGG), resulting in an amino acid change (G357R) in the patient, his father, as well as in his sister. This latter mutation had been previously described in individuals from Moroccan Sephardic Jewish ancestry. Since both heterozygous mutations were found in the patient as well as in his asymptomatic sister, we analyse other meningococcal defence mechanisms such as polymorphisms of the opsonin receptors on polymorphonuclear cells. Results showed that the patient and his sister bore identical combinations of FcgammaRIIA-H/R131 and FcgammaRIIIB-NA1/2 allotypes. Our results provide further evidence that the molecular pathogenesis of C7 deficiency as well as susceptibility to meningococcal disease are heterogeneous, since different families carry different molecular defects, although many of the C7 defects appear to be homogeneous in individuals from certain geographical areas. The missense mutation G357R would make an interesting topic of analysis with regard to meningococcal disease susceptibility in the Spanish population. PMID:12869030

  19. A hypoxia complement differentiates the muscle response to endurance exercise.

    Science.gov (United States)

    Schmutz, Silvia; Däpp, Christoph; Wittwer, Matthias; Durieux, Anne-Cécile; Mueller, Matthias; Weinstein, Felix; Vogt, Michael; Hoppeler, Hans; Flück, Martin

    2010-06-01

    Metabolic stress is believed to constitute an important signal for training-induced adjustments of gene expression and oxidative capacity in skeletal muscle. We hypothesized that the effects of endurance training on expression of muscle-relevant transcripts and ultrastructure would be specifically modified by a hypoxia complement during exercise due to enhanced glycolytic strain. Endurance training of untrained male subjects in conditions of hypoxia increased subsarcolemmal mitochondrial density in the recruited vastus lateralis muscle and power output in hypoxia more than training in normoxia, i.e. 169 versus 91% and 10 versus 6%, respectively, and tended to differentially elevate sarcoplasmic volume density (42 versus 20%, P = 0.07). The hypoxia-specific ultrastructural adjustments with training corresponded to differential regulation of the muscle transcriptome by single and repeated exercise between both oxygenation conditions. Fine-tuning by exercise in hypoxia comprised gene ontologies connected to energy provision by glycolysis and fat metabolism in mitochondria, remodelling of capillaries and the extracellular matrix, and cell cycle regulation, but not fibre structure. In the untrained state, the transcriptome response during the first 24 h of recovery from a single exercise bout correlated positively with changes in arterial oxygen saturation during exercise and negatively with blood lactate. This correspondence was inverted in the trained state. The observations highlight that the expression response of myocellular energy pathways to endurance work is graded with regard to metabolic stress and the training state. The exposed mechanistic relationship implies that the altitude specificity of improvements in aerobic performance with a 'living low-training high' regime has a myocellular basis. PMID:20176680

  20. Identification of rose phenylacetaldehyde synthase by functional complementation in yeast.

    Science.gov (United States)

    Farhi, Moran; Lavie, Orly; Masci, Tania; Hendel-Rahmanim, Keren; Weiss, David; Abeliovich, Hagai; Vainstein, Alexander

    2010-02-01

    Rose flowers, like flowers and fruits of many other plants, produce and emit the aromatic volatiles 2-phenylacetaldehyde (PAA) and 2-phenylethylalchohol (PEA) which have a distinctive flowery/rose-like scent. Previous studies in rose have shown that, similar to petunia flowers, PAA is formed from L: -phenylalanine via pyridoxal-5'-phosphate-dependent L: -aromatic amino acid decarboxylase. Here we demonstrate the use of a Saccharomyces cerevisiae aro10 mutant to functionally characterize a Rosa hybrida cv. Fragrance Cloud sequence (RhPAAS) homologous to petunia phenylacetaldehyde synthase (PhPAAS). Volatile headspace analysis of the aro10 knockout strain showed that it produces up to eight times less PAA and PEA than the WT. Expression of RhPAAS in aro10 complemented the yeast's mutant phenotype and elevated PAA levels, similar to petunia PhPAAS. PEA production levels were also enhanced in both aro10 and WT strains transformed with RhPAAS, implying an application for metabolic engineering of PEA biosynthesis in yeast. Characterization of spatial and temporal RhPAAS transcript accumulation in rose revealed it to be specific to floral tissues, peaking in mature flowers, i.e., coinciding with floral scent production and essentially identical to other rose scent-related genes. RhPAAS transcript, as well as PAA and PEA production in flowers, displayed a daily rhythmic behavior, reaching peak levels during the late afternoon hours. Examination of oscillation of RhPAAS transcript levels under free-running conditions suggested involvement of the endogenous clock in the regulation of RhPAAS expression in rose flowers. PMID:19882107

  1. Atypical haemolytic uraemic syndrome associated with a hybrid complement gene.

    Directory of Open Access Journals (Sweden)

    Julian P Venables

    2006-10-01

    Full Text Available BACKGROUND: Sequence analysis of the regulators of complement activation (RCA cluster of genes at chromosome position 1q32 shows evidence of several large genomic duplications. These duplications have resulted in a high degree of sequence identity between the gene for factor H (CFH and the genes for the five factor H-related proteins (CFHL1-5; aliases CFHR1-5. CFH mutations have been described in association with atypical haemolytic uraemic syndrome (aHUS. The majority of the mutations are missense changes that cluster in the C-terminal region and impair the ability of factor H to regulate surface-bound C3b. Some have arisen as a result of gene conversion between CFH and CFHL1. In this study we tested the hypothesis that nonallelic homologous recombination between low-copy repeats in the RCA cluster could result in the formation of a hybrid CFH/CFHL1 gene that predisposes to the development of aHUS. METHODS AND FINDINGS: In a family with many cases of aHUS that segregate with the RCA cluster we used cDNA analysis, gene sequencing, and Southern blotting to show that affected individuals carry a heterozygous CFH/CFHL1 hybrid gene in which exons 1-21 are derived from CFH and exons 22/23 from CFHL1. This hybrid encodes a protein product identical to a functionally significant CFH mutant (c.3572C>T, S1191L and c.3590T>C, V1197A that has been previously described in association with aHUS. CONCLUSIONS: CFH mutation screening is recommended in all aHUS patients prior to renal transplantation because of the high risk of disease recurrence post-transplant in those known to have a CFH mutation. Because of our finding it will be necessary to implement additional screening strategies that will detect a hybrid CFH/CFHL1 gene.

  2. The atmospheric escape at Mars: complementing the scenario

    Science.gov (United States)

    Lilensten, Jean; Simon, Cyril; Barthélémy, Mathieu; Thissen, Roland; Ehrenreich, David; Gronoff, Guillaume; Witasse, Olivier

    2013-04-01

    In the recent years, the presence of dications in the atmospheres of Mars, Venus, Earth and Titan has been modeled and assessed. These studies also suggested that these ions could participate to the escape of the planetary atmospheres because a large fraction of them is unstable and highly ener- getic. When they dissociate, their internal energy is transformed into kinetic energy which may be larger than the escape energy. This study assesses the impact of the doubly-charged ions in the escape of CO2-dominated planetary atmospheres and to compare it to the escape of thermal photo-ions.We solve a Boltzmann transport equation at daytime taking into account the dissociative states of CO++ for a simplified single constituent atmosphere of a 2 case-study planet. We compute the escape of fast ions using a Beer-Lambert approach. We study three test-cases. On a Mars-analog planet in today's conditions, we retrieve the measured electron escape flux. When comparing the two mechanisms (i.e. excluding solar wind effects, sputtering ...), the escape due to the fast ions issuing from the dissociation of dications may account for up to 6% of the total and the escape of thermal ions for the remaining. We show that these two mechanisms cannot explain the escape of the atmosphere since the magnetic field vanished but complement the other processes and allow writing the scenario of the Mars escape. We show that the atmosphere of a Mars analog planet would empty in another giga years and a half. At Venus orbit, the contribution of the dications in the escape rate is negligible.When simulating the hot Jupiter HD209458b, the two processes cannot explain the measured escape flux of C+.

  3. Fluorescence analyzer for lignin

    Science.gov (United States)

    Berthold, John W.; Malito, Michael L.; Jeffers, Larry

    1993-01-01

    A method and apparatus for measuring lignin concentration in a sample of wood pulp or black liquor comprises a light emitting arrangement for emitting an excitation light through optical fiber bundles into a probe which has an undiluted sensing end facing the sample. The excitation light causes the lignin concentration to produce fluorescent emission light which is then conveyed through the probe to analyzing equipment which measures the intensity of the emission light. Measures a This invention was made with Government support under Contract Number DOE: DE-FC05-90CE40905 awarded by the Department of Energy (DOE). The Government has certain rights in this invention.

  4. Fluorescent temperature sensor

    Science.gov (United States)

    Baker, Gary A [Los Alamos, NM; Baker, Sheila N [Los Alamos, NM; McCleskey, T Mark [Los Alamos, NM

    2009-03-03

    The present invention is a fluorescent temperature sensor or optical thermometer. The sensor includes a solution of 1,3-bis(1-pyrenyl)propane within a 1-butyl-1-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ionic liquid solvent. The 1,3-bis(1-pyrenyl)propane remains unassociated when in the ground state while in solution. When subjected to UV light, an excited state is produced that exists in equilibrium with an excimer. The position of the equilibrium between the two excited states is temperature dependent.

  5. Microfluidic flow cytometer for quantifying photobleaching of fluorescent proteins in cells.

    Science.gov (United States)

    Lubbeck, Jennifer L; Dean, Kevin M; Ma, Hairong; Palmer, Amy E; Jimenez, Ralph

    2012-05-01

    Traditional flow cytometers are capable of rapid cellular assays on the basis of fluorescence intensity and light scatter. Microfluidic flow cytometers have largely followed the same path of technological development as their traditional counterparts; however, the significantly smaller transport distance and resulting lower cell speeds in microchannels provides for the opportunity to detect novel spectroscopic signatures based on multiple, nontemporally coincident excitation beams. Here, we characterize the design and operation of a cytometer with a three-beam, probe/bleach/probe geometry, employing HeLa suspension cells expressing fluorescent proteins. The data collection rate exceeds 20 cells/s under a range of beam intensities (5 kW to 179 kW/cm(2)). The measured percent photobleaching (ratio of fluorescence intensities excited by the first and third beams: S(beam3)/S(beam1)) partially resolves a mixture of four red fluorescent proteins in mixed samples. Photokinetic simulations are presented and demonstrate that the percent photobleaching reflects a combination of the reversible and irreversible photobleaching kinetics. By introducing a photobleaching optical signature, which complements traditional fluorescence intensity-based detection, this method adds another dimension to multichannel fluorescence cytometry and provides a means for flow-cytometry-based screening of directed libraries of fluorescent protein photobleaching. PMID:22424298

  6. Understanding of the Effects of Ionic Strength on the Bimolecular Rate Constant between Structurally Identified Redox Enzymes and Charged Substrates Using Numerical Simulations on the Basis of the Poisson-Boltzmann Equation.

    Science.gov (United States)

    Sugimoto, Yu; Kitazumi, Yuki; Shirai, Osamu; Yamamoto, Masahiro; Kano, Kenji

    2016-03-31

    To understand electrostatic interactions in biomolecules, the bimolecular rate constants (k) between redox enzymes and charged substrates (in this study, redox mediators in the electrode reaction) were evaluated at various ionic strengths (I) for the mediated bioelectrocatalytic reaction. The k value between bilirubin oxidase (BOD) and positively charged mediators increased with I, while that between BOD and negatively charged mediators decreased with I. The opposite trend was observed for the reaction of glucose oxidase (GOD). In the case of noncharged mediators, the k value was independent of I for both BOD and GOD. These results reflect the electrostatic interactions between the enzymes and the mediators. Furthermore, we estimated k/k° (k° being the thermodynamic rate constant) by numerical simulation (finite element method) based on the Poisson-Boltzmann (PB) equation. By considering the charges of individual atoms involved in the amino acids around the substrate binding sites in the enzymes, the simulated k/k° values well reproduced the experimental data. In conclusion, k/k° can be predicted by PB-based simulation as long as the crystal structure of the enzyme and the substrate binding site are known. PMID:26956542

  7. A fluorescence scanning electron microscope

    Directory of Open Access Journals (Sweden)

    Takaaki Kanemaru

    2010-01-01

    Full Text Available Fluorescence techniques are widely used in biological research to examine molecular localization, while electron microscopy can provide unique ultrastructural information. To date, correlative images from both fluorescence and electron microscopy have been obtained separately using two different instruments, i.e. a fluorescence microscope (FM and an electron microscope (EM. In the current study, a scanning electron microscope (SEM (JEOL JXA8600 M was combined with a fluorescence digital camera microscope unit and this hybrid instrument was named a fluorescence SEM (FL-SEM. In the labeling of FL-SEM samples, both Fluolid, which is an organic EL dye, and Alexa Fluor, were employed. We successfully demonstrated that the FL-SEM is a simple and practical tool for correlative fluorescence and electron microscopy.

  8. A study on serum anti-dsDNA antibody and complement in systemic lupus erythematosus (SLE)

    International Nuclear Information System (INIS)

    In this experiment, serum anti-dsDNA antiboby and complement were measured in patients with systemic lupus erythematosus (SLE), patients with other disease control and healthy normal to assess the diagnostic usefulness of anti-dsDNA antibody by radioimmunoassay and determine the degree of correlation between anti-dsDNA antibody and complement

  9. Complement component C3 and risk of age-related macular degeneration

    NARCIS (Netherlands)

    D.D.G. Despriet; C.M. van Duijn; B.A. Oostra; A.G. Uitterlinden; A. Hofman; A.F. Wright; J.B. ten Brink; A. Bakker; P.T.V.M. de Jong; J.R. Vingerling; A.A.B. Bergen; C.C.W. Klaver

    2009-01-01

    OBJECTIVE: To explore the association between polymorphisms in the complement component 3 (C3) gene and age-related macular degeneration (AMD), and to investigate the modifying effect of complement factor H (CFH) Y402H, LOC387715 A69S and smoking. DESIGN: Pooled data from the prospective, population

  10. An assay for the mannan-binding lectin pathway of complement activation

    DEFF Research Database (Denmark)

    Petersen, Steen Vang; Thiel, S; Jensen, L;

    2001-01-01

    ). When bound to microorganisms, the MBL complex activates the complement components C4 and C2, thereby generating the C3 convertase and leading to opsonisation by the deposition of C4b and C3b fragments. This C4/C2 cleaving activity is shared with the C1 complex of the classical pathway of complement...

  11. Von Neumann algebras as complemented subspaces of B(H)

    DEFF Research Database (Denmark)

    Christensen, Erik; Wang, Liguang

    2014-01-01

    Let M be a von Neumann algebra of type II1 which is also a complemented subspace of B( H). We establish an algebraic criterion, which ensures that M is an injective von Neumann algebra. As a corollary we show that if M is a complemented factor of type II1 on a Hilbert space H, then M is injective...

  12. Isometric uniqueness of a complementably universal Banach space for Schauder decompositions

    OpenAIRE

    Garbulińska, Joanna

    2014-01-01

    We present an isometric version of the complementably universal Banach space $\\mathbb{P}$ with a Schauder decomposition. The space $\\mathbb{P}$ is isomorphic to Pe{\\l}czy\\'nski's space with a universal basis as well as to Kadec' complementably universal space with the bounded approximation property.

  13. The complement system and its role in the pathogenesis of periodontitis

    DEFF Research Database (Denmark)

    Damgaard, Christian; Holmstrup, Palle; Van Dyke, Thomas E.; Nielsen, Claus Henrik

    2015-01-01

    Periodontitis is a highly prevalent inflammatory disease in tooth supporting tissues, induced by bacteria growing in a biofilm on tooth surfaces. Components of the complement system are present in the periodontal tissue and the system is activated in periodontitis. Continuous complement activation...

  14. [Separation of lysozyme from sera with complement or antibody activities (author's transl)].

    Science.gov (United States)

    Müller, F; Oetting, C; Beck, E

    1975-10-01

    A gel-filtration method for separating lysozyme from sera with haemolytic complement activity and/or antibody activity is described. It is shown that the gel-filtration has only a small effect, whereas bentonite absorption results in a known lost of haemolytic complement activity. PMID:129979

  15. Syntactic and Semantic Coordination in Finite Complement-Clause Constructions: A Diary-Based Case Study

    Science.gov (United States)

    Köymen, Bahar; Lieven, Elena; Brandt, Silke

    2016-01-01

    This study investigates the coordination of matrix and subordinate clauses within finite complement-clause constructions. The data come from diary and audio recordings which include the utterances produced by an American English-speaking child, L, between the ages 1;08 and 3;05. We extracted all the finite complement-clause constructions that L…

  16. Complement-mediated tumour growth: implications for cancer nanotechnology and nanomedicines

    DEFF Research Database (Denmark)

    Moghimi, S. M.; Andresen, Thomas Lars

    2009-01-01

    The recent unexpected observation that complement activation helps turnout growth and progression has an important bearing on the future development of cancer nanomedicines for site-specific tumour targeting as these entities are capable of triggering complement. These issues are discussed and su...

  17. Complement activation patterns in atypical haemolytic uraemic syndrome during acute phase and in remission

    NARCIS (Netherlands)

    Volokhina, E.B.; Westra, D.; Velden, T.J.A.M. van der; Kar, N.C.A.J. van de; Mollnes, T.E.; Heuvel, B. van den

    2015-01-01

    Atypical haemolytic uraemic syndrome (aHUS) is associated with (genetic) alterations in alternative complement pathway. Nevertheless, comprehensive evidence that the complement system in aHUS patients is more prone to activation is still lacking. Therefore, we performed a thorough analysis of comple

  18. Exploring the Innate Immune System: Using Complement-Medicated Cell Lysis in the Classroom

    Science.gov (United States)

    Fuller, Kevin G.

    2008-01-01

    The protein complement pathway comprises an important part of the innate immunity. The use of serum to demonstrate complement-mediated destruction across a series of bacterial dilutions allows an instructor to introduce a number of important biological concepts such as bacterial growth, activation cascades, and adaptive versus innate immunity.

  19. Complement-mediated enhancement of HIV-1 infection in peripheral blood mononuclear cells

    DEFF Research Database (Denmark)

    Nielsen, S D; Sørensen, A M; Schønning, Kristian; Lund, O; Nielsen, Jens Ole; Hansen, J E

    1997-01-01

    We investigated if complement-mediated enhancement of HIV infection occurs in peripheral blood mononuclear cells (PBMC). In 7 experiments, we evaluated the effect of human complement on HIVIIIB infection in vitro. We measured HIV antigen production on day 4 and found that pre-incubation of HIV with...

  20. Classical complement pathway activation in the kidneys of women with preeclampsia

    NARCIS (Netherlands)

    Penning, Marlies; Chua, Jamie S.; Van Kooten, Cees; Zandbergen, Malu; Buurma, Aletta; Schutte, Joke; Bruijn, Jan Anthonie; Khankin, Eliyahu V.; Bloemenkamp, Kitty; Karumanchi, S. Ananth; Baelde, Hans

    2015-01-01

    A growing body of evidence suggests that complement dysregulation plays a role in the pathogenesis of preeclampsia. The kidney is one of the major organs affected in preeclampsia. Because the kidney is highly susceptible to complement activation, we hypothesized that preeclampsia is associated with

  1. SALO, a novel classical pathway complement inhibitor from saliva of the sand fly Lutzomyia longipalpis.

    Science.gov (United States)

    Ferreira, Viviana P; Fazito Vale, Vladimir; Pangburn, Michael K; Abdeladhim, Maha; Mendes-Sousa, Antonio Ferreira; Coutinho-Abreu, Iliano V; Rasouli, Manoochehr; Brandt, Elizabeth A; Meneses, Claudio; Lima, Kolyvan Ferreira; Nascimento Araújo, Ricardo; Pereira, Marcos Horácio; Kotsyfakis, Michalis; Oliveira, Fabiano; Kamhawi, Shaden; Ribeiro, Jose M C; Gontijo, Nelder F; Collin, Nicolas; Valenzuela, Jesus G

    2016-01-01

    Blood-feeding insects inject potent salivary components including complement inhibitors into their host's skin to acquire a blood meal. Sand fly saliva was shown to inhibit the classical pathway of complement; however, the molecular identity of the inhibitor remains unknown. Here, we identified SALO as the classical pathway complement inhibitor. SALO, an 11 kDa protein, has no homology to proteins of any other organism apart from New World sand flies. rSALO anti-complement activity has the same chromatographic properties as the Lu. longipalpis salivary gland homogenate (SGH)counterparts and anti-rSALO antibodies blocked the classical pathway complement activity of rSALO and SGH. Both rSALO and SGH inhibited C4b deposition and cleavage of C4. rSALO, however, did not inhibit the protease activity of C1s nor the enzymatic activity of factor Xa, uPA, thrombin, kallikrein, trypsin and plasmin. Importantly, rSALO did not inhibit the alternative or the lectin pathway of complement. In conclusion our data shows that SALO is a specific classical pathway complement inhibitor present in the saliva of Lu. longipalpis. Importantly, due to its small size and specificity, SALO may offer a therapeutic alternative for complement classical pathway-mediated pathogenic effects in human diseases. PMID:26758086

  2. SALO, a novel classical pathway complement inhibitor from saliva of the sand fly Lutzomyia longipalpis

    Science.gov (United States)

    Ferreira, Viviana P.; Fazito Vale, Vladimir; Pangburn, Michael K.; Abdeladhim, Maha; Ferreira Mendes-Sousa, Antonio; Coutinho-Abreu, Iliano V.; Rasouli, Manoochehr; Brandt, Elizabeth A.; Meneses, Claudio; Lima, Kolyvan Ferreira; Nascimento Araújo, Ricardo; Horácio Pereira, Marcos; Kotsyfakis, Michalis; Oliveira, Fabiano; Kamhawi, Shaden; Ribeiro, Jose M. C.; Gontijo, Nelder F.; Collin, Nicolas; Valenzuela, Jesus G.

    2016-01-01

    Blood-feeding insects inject potent salivary components including complement inhibitors into their host’s skin to acquire a blood meal. Sand fly saliva was shown to inhibit the classical pathway of complement; however, the molecular identity of the inhibitor remains unknown. Here, we identified SALO as the classical pathway complement inhibitor. SALO, an 11 kDa protein, has no homology to proteins of any other organism apart from New World sand flies. rSALO anti-complement activity has the same chromatographic properties as the Lu. longipalpis salivary gland homogenate (SGH)counterparts and anti-rSALO antibodies blocked the classical pathway complement activity of rSALO and SGH. Both rSALO and SGH inhibited C4b deposition and cleavage of C4. rSALO, however, did not inhibit the protease activity of C1s nor the enzymatic activity of factor Xa, uPA, thrombin, kallikrein, trypsin and plasmin. Importantly, rSALO did not inhibit the alternative or the lectin pathway of complement. In conclusion our data shows that SALO is a specific classical pathway complement inhibitor present in the saliva of Lu. longipalpis. Importantly, due to its small size and specificity, SALO may offer a therapeutic alternative for complement classical pathway-mediated pathogenic effects in human diseases. PMID:26758086

  3. Recombination with coat protein transgene in a complemen-tation system based on Cucumber mosaic virus (CMV)

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In order to study the feasibility of Cucumber mosaic virus (CMV) as an expression vector, the full-length cDNA of RNA 3 from strain SD was cloned and the sequence around the start codon of the coat protein (CP) gene was modified to create an NsiⅠ site for insertion of foreign genes. The CP gene was replaced by the green fluorescent protein (GFP) gene. The cDNAs of Fny RNAs 1 and 2 and the chimeric SD RNA 3 were cloned between the modified 35S promoter and terminator. Tobacco protoplasts were transfected with a mixture of the viral cDNAs containing 35S promoter and terminator as a replacement vector and expressed GFP. A complementation system was established when the replacement vector was inoculated onto the transgenic tobacco plants ex-pressing SD-CMV CP. GFP was detected in the inoculated leaves in 5 of 18 tested plants and in the first upper systemic leaf of one of the 5 plants ten days after inoculation. However, no GFP could be detected in all the plants one month after inoculation. Recombination between the CMV vector and the CP transgene was proved by retro-transcriptional polymerase chain reaction (RT-PCR) and verified by DNA sequencing. Our results argue against the feasibility of the CMV-based replace-ment vector trans-complemented by the CP transgene, and at the same time, enlighten ways to improve the CMV-based expression vector and the biosafety of CMV CP-mediated virus resistant transgenic plants.

  4. Secretion of a fungal protease represents a complement evasion mechanism in cerebral aspergillosis.

    Science.gov (United States)

    Rambach, Günter; Dum, David; Mohsenipour, Iradj; Hagleitner, Magdalena; Würzner, Reinhard; Lass-Flörl, Cornelia; Speth, Cornelia

    2010-04-01

    Complement represents a central immune weapon in the brain, but the high lethality of cerebral aspergillosis indicates a low efficacy of the antifungal complement attack. Studies with cerebrospinal fluid (CSF) samples derived from a patient with cerebral aspergillosis showed a degradation of complement proteins, implying that Aspergillus might produce proteases to evade their antimicrobial potency. Further investigations of this hypothesis showed that Aspergillus, when cultured in CSF to simulate growth conditions in the brain, secreted a protease that can cleave various complement proteins. Aspergillus fumigatus, the most frequent cause of cerebral aspergillosis, destroyed complement activity more efficiently than other Aspergillus species. The degradation of complement in CSF resulted in a drastic reduction of the capacity to opsonize fungal hyphae. Furthermore, the Aspergillus-derived protease could diminish the amount of complement receptor CR3, a surface molecule to mediate eradication of opsonized pathogens, on granulocytes and microglia. The lack of these prerequisites caused a significant decrease in phagocytosis of primary microglia. Additional studies implied that the complement-degrading activity shares many characteristics with the previously described alkaline protease Alp1. To improve the current therapy for cerebral aspergillosis, we tried to regain the antifungal effects of complement by repressing the secretion of this degrading activity. Supplementation of CSF with nitrogen sources rescued the complement proteins and abolished any cleavage. Glutamine or arginine are of special interest for this purpose since they represent endogenous substances in the CNS and might be included in a future supportive therapy to reduce the high lethality of cerebral aspergillosis. PMID:20303595

  5. Interaction between complement subcomponent C1q and bacterial lipopolysaccharides.

    Science.gov (United States)

    Zohair, A; Chesne, S; Wade, R H; Colomb, M G

    1989-02-01

    The heptose-less mutant of Escherichia coli, D31m4, bound complement subcomponent C1q and its collagen-like fragments (C1qCLF) with Ka values of 1.4 x 10(8) and 2.0 x 10(8) M-1 respectively. This binding was suppressed by chemical modification of C1q and C1qCLF using diethyl pyrocarbonate (DEPC). To investigate the role of lipopolysaccharides (LPS) in this binding, biosynthetically labelled [14C]LPS were purified from E. coli D31m4 and incorporated into liposomes prepared from phosphatidylcholine (PC) and phosphatidylethanolamine (PE) [PC/PE/LPS, 2:2:1, by wt.]. Binding of C1q or its collagen-like fragments to the liposomes was estimated via a flotation test. These liposomes bound C1q and C1qCLF with Ka values of 8.0 x 10(7) and 2.0 x 10(7) M-1; this binding was totally inhibited after chemical modification of C1q and C1qCLF by DEPC. Liposomes containing LPS purified from the wild-strain E. coli K-12 S also bound C1q and C1qCLF, whereas direct binding of C1q or C1qCLF to the bacteria was negligible. Diamines at concentrations which dissociate C1 into C1q and (C1r, C1s)2, strongly inhibited the interaction of C1q or C1qCLF with LPS. Removal of 3-deoxy-D-manno-octulosonic acid (2-keto-3-deoxyoctonic acid; KDO) from E. coli D31m4 LPS decreases the binding of C1qCLF to the bacteria by 65%. When this purified and modified LPS was incorporated into liposomes, the C1qCLF binding was completely abolished. These results show: (i) the essential role of the collagen-like moiety and probably its histidine residues in the interaction between C1q and the mutant D31m4; (ii) the contribution of LPS, particularly the anionic charges of KDO, to this interaction. PMID:2649081

  6. Further structural insights into the binding of complement factor H by complement regulator-acquiring surface protein 1 (CspA) of Borrelia burgdorferi

    International Nuclear Information System (INIS)

    B. burgdorferi binds complement factor H using a dimeric surface protein, CspA (BbCRASP-1). Presented here is a new structure of CspA that suggests that there is a degree of flexibility between subunits which may have implications for complement regulator binding. Borrelia burgdorferi has evolved many mechanisms of evading the different immune systems across its range of reservoir hosts, including the capture and presentation of host complement regulators factor H and factor H-like protein-1 (FHL-1). Acquisition is mediated by a family of complement regulator-acquiring surface proteins (CRASPs), of which the atomic structure of CspA (BbCRASP-1) is known and shows the formation of a homodimeric species which is required for binding. Mutagenesis studies have mapped a putative factor H binding site to a cleft between the two subunits. Presented here is a new atomic structure of CspA which shows a degree of flexibility between the subunits which may be critical for factor H scavenging by increasing access to the binding interface and allows the possibility that the assembly can clamp around the bound complement regulators

  7. Versatile protein tagging in cells with split fluorescent protein.

    Science.gov (United States)

    Kamiyama, Daichi; Sekine, Sayaka; Barsi-Rhyne, Benjamin; Hu, Jeffrey; Chen, Baohui; Gilbert, Luke A; Ishikawa, Hiroaki; Leonetti, Manuel D; Marshall, Wallace F; Weissman, Jonathan S; Huang, Bo

    2016-01-01

    In addition to the popular method of fluorescent protein fusion, live cell protein imaging has now seen more and more application of epitope tags. The small size of these tags may reduce functional perturbation and enable signal amplification. To address their background issue, we adapt self-complementing split fluorescent proteins as epitope tags for live cell protein labelling. The two tags, GFP11 and sfCherry11 are derived from the eleventh β-strand of super-folder GFP and sfCherry, respectively. The small size of FP11-tags enables a cost-effective and scalable way to insert them into endogenous genomic loci via CRISPR-mediated homology-directed repair. Tandem arrangement FP11-tags allows proportional enhancement of fluorescence signal in tracking intraflagellar transport particles, or reduction of photobleaching for live microtubule imaging. Finally, we show the utility of tandem GFP11-tag in scaffolding protein oligomerization. These experiments illustrate the versatility of FP11-tag as a labelling tool as well as a multimerization-control tool for both imaging and non-imaging applications. PMID:26988139

  8. Regulation of Latent Membrane Protein 1 Signaling through Interaction with Cytoskeletal Proteins

    OpenAIRE

    Holthusen, Kirsten; Talaty, Pooja; Everly, David N.

    2015-01-01

    Latent membrane protein 1 (LMP1) of Epstein-Barr virus (EBV) induces constitutive signaling in EBV-infected cells to ensure the survival of the latently infected cells. LMP1 is localized to lipid raft domains to induce signaling. In the present study, a genome-wide screen based on bimolecular fluorescence complementation (BiFC) was performed to identify LMP1-binding proteins. Several actin cytoskeleton-associated proteins were identified in the screen. Overexpression of these proteins affecte...

  9. HIV-1 Nef Dimerization is required for Nef-Mediated Receptor Downregulation and Viral Replication

    OpenAIRE

    Poe, Jerrod A.; Smithgall, Thomas E

    2009-01-01

    Nef, an HIV-1 accessory factor capable of interaction with a diverse array of host cell signaling molecules, is essential for high-titer HIV replication and AIDS progression. Previous biochemical and structural studies have suggested that Nef may form homodimers and higher order oligomers in HIV-infected cells, which may be required for both immune and viral receptor downregulation as well as viral replication. Using bimolecular fluorescence complementation (BiFC), we provide the first direct...

  10. Collectin-11/MASP complex formation triggers activation of the lectin complement pathway--the fifth lectin pathway initiation complex

    DEFF Research Database (Denmark)

    Ma, Ying Jie; Skjoedt, Mikkel-Ole; Garred, Peter

    2013-01-01

    complement pathway regulator MAP-1. Furthermore, we found that complex formation between recombinant collectin-11 and recombinant MASP-2 on Candida albicans leads to deposition of C4b. Native collectin-11 in serum mediated complement activation and deposition of C4b and C3b, and formation of the terminal...... complement complex on C. albicans. Moreover, spiking collectin-11-depleted serum, which did not mediate complement activation, with recombinant collectin-11 restored the complement activation capability. These results define collectin-11 as the fifth recognition molecule in the lectin complement pathway in...

  11. A De Novo Deletion in the Regulators of Complement Activation Cluster Producing a Hybrid Complement Factor H/Complement Factor H-Related 3 Gene in Atypical Hemolytic Uremic Syndrome.

    Science.gov (United States)

    Challis, Rachel C; Araujo, Geisilaine S R; Wong, Edwin K S; Anderson, Holly E; Awan, Atif; Dorman, Anthony M; Waldron, Mary; Wilson, Valerie; Brocklebank, Vicky; Strain, Lisa; Morgan, B Paul; Harris, Claire L; Marchbank, Kevin J; Goodship, Timothy H J; Kavanagh, David

    2016-06-01

    The regulators of complement activation cluster at chromosome 1q32 contains the complement factor H (CFH) and five complement factor H-related (CFHR) genes. This area of the genome arose from several large genomic duplications, and these low-copy repeats can cause genome instability in this region. Genomic disorders affecting these genes have been described in atypical hemolytic uremic syndrome, arising commonly through nonallelic homologous recombination. We describe a novel CFH/CFHR3 hybrid gene secondary to a de novo 6.3-kb deletion that arose through microhomology-mediated end joining rather than nonallelic homologous recombination. We confirmed a transcript from this hybrid gene and showed a secreted protein product that lacks the recognition domain of factor H and exhibits impaired cell surface complement regulation. The fact that the formation of this hybrid gene arose as a de novo event suggests that this cluster is a dynamic area of the genome in which additional genomic disorders may arise. PMID:26490391

  12. Assessing Photosynthesis by Fluorescence Imaging

    Science.gov (United States)

    Saura, Pedro; Quiles, Maria Jose

    2011-01-01

    This practical paper describes a novel fluorescence imaging experiment to study the three processes of photochemistry, fluorescence and thermal energy dissipation, which compete during the dissipation of excitation energy in photosynthesis. The technique represents a non-invasive tool for revealing and understanding the spatial heterogeneity in…

  13. X-ray Fluorescence Sectioning

    CERN Document Server

    Cong, Wenxiang

    2012-01-01

    In this paper, we propose an x-ray fluorescence imaging system for elemental analysis. The key idea is what we call "x-ray fluorescence sectioning". Specifically, a slit collimator in front of an x-ray tube is used to shape x-rays into a fan-beam to illuminate a planar section of an object. Then, relevant elements such as gold nanoparticles on the fan-beam plane are excited to generate x-ray fluorescence signals. One or more 2D spectral detectors are placed to face the fan-beam plane and directly measure x-ray fluorescence data. Detector elements are so collimated that each element only sees a unique area element on the fan-beam plane and records the x-ray fluorescence signal accordingly. The measured 2D x-ray fluorescence data can be refined in reference to the attenuation characteristics of the object and the divergence of the beam for accurate elemental mapping. This x-ray fluorescence sectioning system promises fast fluorescence tomographic imaging without a complex inverse procedure. The design can be ad...

  14. Spontaneous complement activation on human B cells results in localized membrane depolarization and the clustering of complement receptor type 2 and C3 fragments

    DEFF Research Database (Denmark)

    Pedersen, Morten Løbner; Leslie, Robert G Q; Prodinger, Wolfgang M;

    2009-01-01

    While our previous studies have demonstrated that complement activation induced by complement receptors type 2 (CR2/CD21) and 1 (CR1/CD35) results in C3-fragment deposition and membrane attack complex (MAC) formation in human B cells, the consequences of these events for B-cell functions remain...... requires activation of complement via the alternative pathway, as indicated by total inhibition upon neutralization of factor D, and is abrogated by combined blockade of CR1 and CR2, but not of either receptor alone. The membrane depolarization is not associated with the apoptosis of B cells, as examined...... by co-staining with APO-2.7 or by the TdT-mediated biotin-dUTP nick-end labelling (TUNEL) assay. Confocal microscopy revealed that depolarization and C3 deposition, unlike MAC deposition, are limited to restricted areas on the B-cell surface. Double staining revealed a close association between the C...

  15. Complement therapeutics in inflammatory diseases: promising drug candidates for C3-targeted intervention.

    Science.gov (United States)

    Mastellos, D C; Ricklin, D; Hajishengallis, E; Hajishengallis, G; Lambris, J D

    2016-02-01

    There is increasing appreciation that complement dysregulation lies at the heart of numerous immune-mediated and inflammatory disorders. Complement inhibitors are therefore being evaluated as new therapeutic options in various clinical translation programs and the first clinically approved complement-targeted drugs have profoundly impacted the management of certain complement-mediated diseases. Among the many members of the intricate protein network of complement, the central component C3 represents a 'hot-spot' for complement-targeted therapeutic intervention. C3 modulates both innate and adaptive immune responses and is linked to diverse immunomodulatory systems and biological processes that affect human pathophysiology. Compelling evidence from preclinical disease models has shown that C3 interception may offer multiple benefits over existing therapies or even reveal novel therapeutic avenues in disorders that are not commonly regarded as complement-driven, such as periodontal disease. Using the clinically developed compstatin family of C3 inhibitors and periodontitis as illustrative examples, this review highlights emerging therapeutic concepts and developments in the design of C3-targeted drug candidates as novel immunotherapeutics for oral and systemic inflammatory diseases. PMID:26332138

  16. Optical Properties of Fluorescent Dyes

    Institute of Scientific and Technical Information of China (English)

    李戎; 陈东辉

    2001-01-01

    Fluorescent dyes have been widely used these years.Because of the special optical performance, conventional CCM systems seem to be unable to predict the recipes of fabrics dyed with fluorescent dyes. In order to enhance the functions of CCM systems, the optical properties of fluorescent dyes in their absorption region were investigated. It has been found that there was a fixed maximum absorption wavelength for each fluorescent dyes whatever its concentration is. Both absorption region and maximum absorption wavelength of the dyes in solution are the same to those in fabric, and that the absorption is directly proportional to the concentration of the dye. So the optical properties obtained in solutions cna be applied for describing the optics performance of fluorescent dyes in fabrics.

  17. Time-resolved fluorescence spectroscopy

    International Nuclear Information System (INIS)

    This article addresses the evolution in time of light emitted by a molecular system after a brief photo-excitation. The authors first describe fluorescence from a photo-physical point of view and discuss the characterization of the excited state. Then, they explain some basic notions related to fluorescence characterization (lifetime and decays, quantum efficiency, so on). They present the different experimental methods and techniques currently used to study time-resolved fluorescence. They discuss basic notions of time resolution and spectral reconstruction. They briefly present some conventional methods: intensified Ccd cameras, photo-multipliers and photodiodes associated with a fast oscilloscope, and phase modulation. Other methods and techniques are more precisely presented: time-correlated single photon counting (principle, examples, and fluorescence lifetime imagery), streak camera (principle, examples), and optical methods like the Kerr optical effect (principle and examples) and fluorescence up-conversion (principle and theoretical considerations, examples of application)

  18. Targeting mechanisms at sites of complement activation for imaging and therapy.

    Science.gov (United States)

    Holers, V Michael

    2016-06-01

    The complement system plays a key role in many acute injury states as well as chronic autoimmune and inflammatory diseases. Localized complement activation and alternative pathway-mediated amplification on diverse target surfaces promote local recruitment of pro-inflammatory cells and elaboration of other mediators. Despite a general understanding of the architecture of the system, though, many of the mechanisms that underlie site-specific complement activation and amplification in vivo are incompletely understood. In addition, there is no capability yet to measure the level of local tissue site-specific complement activation in patients without performing biopsies to detect products using immunohistochemical techniques. Herein is reviewed emerging evidence obtained through clinical research studies of human rheumatoid arthritis along with translational studies of its disease models which demonstrate that several parallel mechanisms are involved in site-specific amplification of activation of the complement system in vivo. Among these processes are de-regulation of the alternative pathway, effector pathway-catalyzed amplification of proximal complement activation, recognition of injury-associated ligands by components of the lectin pathway, and engagement of pathogenic natural antibodies that recognize a limited set of injury-associated neoepitopes. Studies suggest that each of these inter-related processes can play key roles in amplification of complement-dependent injury on self-tissues in vivo. These findings, in addition to development of an imaging strategy described herein designed to quantitatively measure local complement C3 fixation, have relevance to therapeutic and diagnostic strategies targeting the complement system. PMID:25979851

  19. Rare loss-of-function mutation in complement component C3 provides insight into molecular and pathophysiological determinants of complement activity

    OpenAIRE

    Sfyroera, Georgia; Ricklin, Daniel; Reis, Edimara S.; Chen, Hui; Wu, Emilia L.; Kaznessis, Yiannis N.; Ekdahl, Kristina N.; Nilsson, Bo; Lambris, John D.

    2015-01-01

    The plasma protein C3 is a central element in the activation and effector functions of the complement system. A hereditary dysfunction of C3 that prevents complement activation via the alternative pathway (AP) was described previously in a Swedish family, but its genetic cause and molecular consequences have remained elusive. Here we provide these missing links by pinpointing the dysfunction to a point mutation in the β-chain of C3 (c.1180T>C; p.Met373Thr). In the patient’s plasma, AP activit...

  20. Dynamic Structural Changes During Complement C3 Activation Analyzed by Hydrogen/Deuterium Exchange Mass Spectrometry

    OpenAIRE

    Schuster, Michael C.; Ricklin, Daniel; Papp, Krisztián; Molnar, Kathleen S.; Coales, Stephen J.; Hamuro, Yoshitomo; Sfyroera, Georgia; Chen, Hui; Winters, Michael S; Lambris, John D.

    2008-01-01

    Proteolytic cleavage of component C3 to C3b is a central step in the activation of complement. Whereas C3 is largely biologically inactive, C3b is directly involved in various complement activities. While the recently described crystal structures of C3 and C3b provide a molecular basis of complement activation, they do not reflect the dynamic changes that occur in solution. In addition, the available C3b structures diverge in some important aspects. Here we have utilized hydrogen/deuterium ex...

  1. Human genetic deficiencies reveal the roles of complement in the inflammatory network: lessons from nature

    DEFF Research Database (Denmark)

    Lappegård, Knut Tore; Christiansen, Dorte; Pharo, Anne;

    2009-01-01

    does not interfere with the complement system. Expression of tissue factor, cell adhesion molecules, and oxidative burst depended highly on C5, mediated through the activation product C5a, whereas granulocyte enzyme release relied mainly on C3 and was C5a-independent. Release of cytokines and......Complement component C5 is crucial for experimental animal inflammatory tissue damage; however, its involvement in human inflammation is incompletely understood. The responses to gram-negative bacteria were here studied taking advantage of human genetic complement-deficiencies--nature's own...

  2. Interactions of the humoral pattern recognition molecule PTX3 with the complement system

    DEFF Research Database (Denmark)

    Doni, Andrea; Garlanda, Cecilia; Bottazzi, Barbara;

    2012-01-01

    The innate immune system comprises a cellular and a humoral arm. The long pentraxin PTX3 is a fluid phase pattern recognition molecule, which acts as an essential component of the humoral arm of innate immunity. PTX3 has antibody-like properties including interactions with complement components....... PTX3 interacts with C1q, ficolin-1 and ficolin-2 as well as mannose-binding lectin, recognition molecules in the classical and lectin complement pathways. The formation of these heterocomplexes results in cooperative pathogen recognition and complement activation. Interactions with C4b binding protein...

  3. Invisible anti-cloak with elliptic cross section using phase complement

    International Nuclear Information System (INIS)

    Based on the theory of phase complement, an anti-cloak with circular cross section can be made invisible to an object outside its domain. As the cloak with elliptic cross section is more effective to make objects invisible than that with circular cross section, a scaled coordinate system is proposed to design equivalent materials of invisible anti-cloak with elliptic cross section using phase complement. The cloaks with conventional dielectric and double negative parameters are both simulated with the geometrical transformations. The results show that the cloak with elliptic cross section through phase complement can effectively hide the outside objects. (classical areas of phenomenology)

  4. Detecting and Quantifying Biomolecular Interactions of a Dendritic Polyglycerol Sulfate Nanoparticle Using Fluorescence Lifetime Measurements

    Directory of Open Access Journals (Sweden)

    Alexander Boreham

    2015-12-01

    Full Text Available Interactions of nanoparticles with biomaterials determine the biological activity that is key for the physiological response. Dendritic polyglycerol sulfates (dPGS were found recently to act as an inhibitor of inflammation by blocking selectins. Systemic application of dPGS would present this nanoparticle to various biological molecules that rapidly adsorb to the nanoparticle surface or lead to adsorption of the nanoparticle to cellular structures such as lipid membranes. In the past, fluorescence lifetime measurements of fluorescently tagged nanoparticles at a molecular and cellular/tissue level have been proven to reveal valuable information on the local nanoparticle environment via characteristic fluorescent lifetime signatures of the nanoparticle bound dye. Here, we established fluorescence lifetime measurements as a tool to determine the binding affinity to fluorescently tagged dPGS (dPGS-ICC; ICC: indocarbocyanine. The binding to a cell adhesion molecule (L-selectin and a human complement protein (C1q to dPGS-ICC was evaluated by the concentration dependent change in the unique fluorescence lifetime signature of dPGS-ICC. The apparent binding affinity was found to be in the nanomolar range for both proteins (L-selectin: 87 ± 4 nM and C1q: 42 ± 12 nM. Furthermore, the effect of human serum on the unique fluorescence lifetime signature of dPGS-ICC was measured and found to be different from the interactions with the two proteins and lipid membranes. A comparison between the unique lifetime signatures of dPGS-ICC in different biological environments shows that fluorescence lifetime measurements of unique dPGS-ICC fluorescence lifetime signatures are a versatile tool to probe the microenvironment of dPGS in cells and tissue.

  5. Shedding Some Light on Fluorescent Bulbs.

    Science.gov (United States)

    Guilbert, Nicholas R.

    1996-01-01

    Explores some of the principles behind the working of fluorescent bulbs using a specially prepared fluorescent bulb with the white inner fluorescent coating applied along only half its length. Discusses the spectrum, the bulb plasma, and light production. (JRH)

  6. Biocompatible fluorescence-enhanced ZrO2-CdTe quantum dot nanocomposite for in vitro cell imaging

    Science.gov (United States)

    Lu, Zhisong; Zhu, Zhihong; Zheng, Xinting; Qiao, Yan; Guo, Jun; Li, Chang Ming

    2011-04-01

    With advances of quantum dots (QDs) in bioimaging applications, various materials have been used to coat QDs to reduce their nanotoxicity; however, the coating could introduce new toxic sources and quench the fluorescence in bioimaging applications. In this work, ZrO2, an excellent ceramic material with low extinction coefficient and good biocompatibility, is utilized to coat CdTe QDs for the first time. Experimental results show that ZrO2-QD nanocomposites with the size of ~ 30 nm possess enhanced fluorescence emission, lower nanotoxicity and gradually increased fluorescence under 350 nm light illumination. After functionalization with folic acid, they were applied to label cultured HeLa cells effectively. Therefore, the ZrO2-QD nanocomposites could be promising biocompatible nanomaterials with strong fluorescence emission to replace or complement QDs in biomedical applications.

  7. Biocompatible fluorescence-enhanced ZrO2-CdTe quantum dot nanocomposite for in vitro cell imaging

    International Nuclear Information System (INIS)

    With advances of quantum dots (QDs) in bioimaging applications, various materials have been used to coat QDs to reduce their nanotoxicity; however, the coating could introduce new toxic sources and quench the fluorescence in bioimaging applications. In this work, ZrO2, an excellent ceramic material with low extinction coefficient and good biocompatibility, is utilized to coat CdTe QDs for the first time. Experimental results show that ZrO2-QD nanocomposites with the size of ∼ 30 nm possess enhanced fluorescence emission, lower nanotoxicity and gradually increased fluorescence under 350 nm light illumination. After functionalization with folic acid, they were applied to label cultured HeLa cells effectively. Therefore, the ZrO2-QD nanocomposites could be promising biocompatible nanomaterials with strong fluorescence emission to replace or complement QDs in biomedical applications.

  8. Strong complement activation after acute ischemic stroke is associated with unfavorable outcomes

    DEFF Research Database (Denmark)

    Széplaki, Gábor; Szegedi, Róbert; Hirschberg, Kristóf;

    2009-01-01

    five complement activation products (C1rC1sC1inh, C4d, C3a, C5a and SC5b-9) in samples of 26 patients with ischemic stroke upon admission. Twenty-six patients with severe carotid atherosclerosis served as patient controls. RESULTS: Levels of two activation products (SC5b-9 and C4d)) were significantly......OBJECTIVE: According to data from animal models, complement activation plays a major role in the brain injury after acute ischemic stroke. Scarce findings are, however, available on the detection of complement activation products in stroke patients. METHODS: We have measured plasma levels of the...... elevated in the plasma of stroke patients, SC5b-9 levels, exhibited significant positive correlation with the clinical severity of stroke, the severity of neurological deficit, as well as with the level of functional disability. CONCLUSION: These findings suggest that complement activation plays an active...

  9. Complement components of nerve regeneration conditioned fluid influence the microenvironment of nerve regeneration

    Directory of Open Access Journals (Sweden)

    Guang-shuai Li

    2016-01-01

    Full Text Available Nerve regeneration conditioned fluid is secreted by nerve stumps inside a nerve regeneration chamber. A better understanding of the proteinogram of nerve regeneration conditioned fluid can provide evidence for studying the role of the microenvironment in peripheral nerve regeneration. In this study, we used cylindrical silicone tubes as the nerve regeneration chamber model for the repair of injured rat sciatic nerve. Isobaric tags for relative and absolute quantitation proteomics technology and western blot analysis confirmed that there were more than 10 complement components (complement factor I, C1q-A, C1q-B, C2, C3, C4, C5, C7, C8ß and complement factor D in the nerve regeneration conditioned fluid and each varied at different time points. These findings suggest that all these complement components have a functional role in nerve regeneration.

  10. Complement activation in Ghanaian children with severe Plasmodium falciparum malaria

    DEFF Research Database (Denmark)

    Helegbe, Gideon K; Goka, Bamenla Q; Kurtzhals, Jørgen;

    2007-01-01

    BACKGROUND: Severe anaemia (SA), intravascular haemolysis (IVH) and respiratory distress (RD) are severe forms of Plasmodium falciparum malaria, with RD reported to be of prognostic importance in African children with malarial anaemia. Complement factors have been implicated in the mechanism...

  11. Activation capacity of the alternative and classic complement pathways in patients operated on for colorectal cancer

    DEFF Research Database (Denmark)

    Zimmermann-Nielsen, Erik; Iversen, Lene H; Svehag, Sven-Erik;

    2002-01-01

    surgery. The samples were analyzed with an enzyme-linked immunosorbent assay that measured C3 activation capacity by the alternative and classic complement pathways. Cancer patients were compared according to Dukes stage, type of surgery performed, transfusion of blood, development of infection, venous......PURPOSE: Tumor cells may suppress activation of the host's complement system, and the functional state of the complement system may be a prognostic marker of outcome in patients with malignancies. Serial plasma samples from patients undergoing intended curative surgery for colorectal cancer were...... analyzed for complement factor C3 activation capacity. METHODS: Samples were collected from 91 patients with colorectal cancer and 13 with benign colorectal diseases before surgery and 1, 2, and 7 days after surgery, between 8 and 13 days after surgery, and 3, 6, 12, 18, 24, 36, 48, and 60 months after...

  12. C1q binding and complement activation by prions and amyloids.

    Science.gov (United States)

    Sim, Robert B; Kishore, Uday; Villiers, Christian L; Marche, Patrice N; Mitchell, Daniel A

    2007-01-01

    C1q binds to many non-self and altered-self-materials. These include microorganisms, immune complexes, apoptotic and necrotic cells and their breakdown products, and amyloids. C1q binding to amyloid fibrils found as extracellular deposits in tissues, and subsequent complement activation are involved in the pathology of several amyloid diseases, such as Alzheimer's disease. Prion diseases, such as scrapie also involve formation of amyloid by polymerization of the host prion protein (PrP). Complement activation is likely to contribute to neuronal damage in the end stages of prion diseases, but is also thought to participate in the initial infection, dissemination and replication stages. Infectious prion particles are likely to bind C1q and activate the complement system. Bound complement proteins may then influence the uptake and transport of prion particles by dendritic cells (DCs) and their subsequent proliferation at sites such as follicular DCs. PMID:17544820

  13. Total haemolytic complement profile in chicks following fowl pox vaccination or infection.

    Science.gov (United States)

    Kapil, S; Das, S K; Kumar, A

    1989-01-01

    Total haemolytic complement levels were assessed in normal, fowl pox-vaccinated or infected chicks using radial immune haemolysis up to 28 days post-treatment. Significantly lower values of total haemolytic complement were recorded 7-21 days post-vaccination or 21 days post-infection as compared to controls (p less than 0.05). The differences between intervals, the influence of the period of treatment were also significant, but the vaccinated chicks did not differ significantly from the infected ones (p less than 0.05). It is concluded that lower circulating levels of total haemolytic complement may be due to deposition of complement at the sites of virus replication. PMID:2565680

  14. Citrem Modulates Internal Nanostructure of Glyceryl Monooleate Dispersions and Bypasses Complement Activation

    DEFF Research Database (Denmark)

    Wibroe, Peter P; Mat Azmi, Intan Diana Binti; Nilsson, Christa;

    2015-01-01

    Lyotropic non-lamellar liquid crystalline (LLC) aqueous nanodispersions hold a great promise in drug solubilization and delivery, but these nanosystems often induce severe hemolysis and complement activation, which limit their applications for safe intravenous administration. Here, we engineer an...

  15. Perioperative functional activity of the alternative pathway of complement in patients with colonic cancer

    DEFF Research Database (Denmark)

    Baatrup, G; Zimmermann-Nielsen, E; Qvist, N

    1999-01-01

    emergency operations for colonic cancer. INTERVENTIONS: Measurements of C3b fixing capacity of the alternative complement pathway in serum before, during, and after operation. MAIN OUTCOME MEASUREMENTS: The functional capacity of the alternative pathway of complement, and changes during operation. RESULTS......OBJECTIVE: To investigate the functional capacity of the alternative pathway of complement in patients with cancer of the colon before, during, and after operation. DESIGN: Prospective study. SETTING: One university and two district hospitals, Denmark. SUBJECTS: 28 patients having elective or...... immunological variable that has so far been shown to have increased functional capacity in patients with cancer, and that remains unaltered (mean value) during operation. The importance of retaining normal function of the alternative complement pathway in the prevention of postoperative infective complications...

  16. Some Experiences with Nonoverlapping Schur Complement Parallel Preconditioning for CFD Calculations

    Science.gov (United States)

    Barth, Timothy J.; Chan, Tony F.; Tang, Wei-Pai; Kwak, Dochan (Technical Monitor)

    1996-01-01

    In this work we consider solving matrices which arise from the discretization of advection-diffusion field equations on arbitrary triangulated domains using stabilized numerical methods. The talk will discuss several candidate matrix preconditioning algorithms based on the 2 x 2 block factorization induced by an apriori partitioning of the triangulated domain. Application of the 2 x 2 block preconditioner requires the formation and inversion of the Schur complement submatrix. We consider several strategies for simplifying this task: incomplete Schur complement factorizations, drop tolerance element filling, Schur complement probing, and localized Schur complement inversion. Numerical results will be shown comparing performance and efficiency of these approximations. The matrix preconditioner has also been embedded into a Newton algorithm for solving the nonlinear Euler and Navier-Stokes equations governing compressible flow. The remainder of the talk will show numerous examples in CFD to demonstrate the efficiency and robustness of the techniques.

  17. Different Host Complement Systems and Their Interactions with Saliva from Lutzomyia longipalpis (Diptera, Psychodidae) and Leishmania infantum Promastigotes

    OpenAIRE

    Antonio Ferreira Mendes-Sousa; Alexandre Alves Sousa Nascimento; Daniel Costa Queiroz; Vladimir Fazito Vale; Ricardo Toshio Fujiwara; Ricardo Nascimento Araújo; Marcos Horácio Pereira; Nelder Figueiredo Gontijo

    2013-01-01

    BACKGROUND: Lutzomyia longipalpis is the vector of Leishmania infantum in the New World, and its saliva inhibits classical and alternative human complement system pathways. This inhibition is important in protecting the insect´s midgut from damage by the complement. L. longipalpis is a promiscuous blood feeder and must be protected against its host's complement. The objective of this study was to investigate the action of salivary complement inhibitors on the sera of different host species, s...

  18. Exploring the potential benefits of vaccinia virus complement control protein in controlling complement activation in pathogenesis of the central nervous system diseases.

    Science.gov (United States)

    Kotwal, Girish J; Fernando, Nilisha; Zhou, Jianhua; Valter, Krisztina

    2014-10-01

    Aging is a major risk factor for the development of diseases related to the central nervous system (CNS), such as Alzheimer's disease (AD) and age-related macular degeneration (AMD). In both cases, linkage studies and genome-wide association studies found strong links with complement regulatory genes and disease risk. In AD, both CLU and CR1 genes were implicated in the late-onset form of the disease. In AMD, polymorphisms in CFH, CFB and C2 were similarly implicated. The cost of caring for patients with AD or AMD is approaching billions of dollars, and with the baby boomers reaching their 60's, this amount is likely to increase further. Intervention using complement inhibitors for individuals in their early 50s who are at a higher risk of disease development, (testing positive for genetic risk factors), could slow the progression of AD or AMD and possibly prevent the severity of late stage symptoms. Although we have used the vaccinia virus complement control protein (VCP) to elucidate the role of complement in CNS diseases, it has merely been an investigational tool but not the only possible potential therapeutic agent. PMID:25052409

  19. The Staphylococcus aureus protein Sbi acts as a complement inhibitor and forms a tripartite complex with host complement Factor H and C3b.

    Directory of Open Access Journals (Sweden)

    Katrin Haupt

    2008-12-01

    Full Text Available The Gram-positive bacterium Staphylococcus aureus, similar to other pathogens, binds human complement regulators Factor H and Factor H related protein 1 (FHR-1 from human serum. Here we identify the secreted protein Sbi (Staphylococcus aureus binder of IgG as a ligand that interacts with Factor H by a-to our knowledge-new type of interaction. Factor H binds to Sbi in combination with C3b or C3d, and forms tripartite SbiratioC3ratioFactor H complexes. Apparently, the type of C3 influences the stability of the complex; surface plasmon resonance studies revealed a higher stability of C3d complexed to Sbi, as compared to C3b or C3. As part of this tripartite complex, Factor H is functionally active and displays complement regulatory activity. Sbi, by recruiting Factor H and C3b, acts as a potent complement inhibitor, and inhibits alternative pathway-mediated lyses of rabbit erythrocytes by human serum and sera of other species. Thus, Sbi is a multifunctional bacterial protein, which binds host complement components Factor H and C3 as well as IgG and beta(2-glycoprotein I and interferes with innate immune recognition.

  20. Fluorescent fluid interface position sensor

    Science.gov (United States)

    Weiss, Jonathan D.

    2004-02-17

    A new fluid interface position sensor has been developed, which is capable of optically determining the location of an interface between an upper fluid and a lower fluid, the upper fluid having a larger refractive index than a lower fluid. The sensor functions by measurement, of fluorescence excited by an optical pump beam which is confined within a fluorescent waveguide where that waveguide is in optical contact with the lower fluid, but escapes from the fluorescent waveguide where that waveguide is in optical contact with the upper fluid.

  1. Blue Fluorescent cGMP Sensor for Multiparameter Fluorescence Imaging

    OpenAIRE

    Niino, Yusuke; Hotta, Kohji; Oka, Kotaro

    2010-01-01

    Cyclic GMP (cGMP) regulates many physiological processes by cooperating with the other signaling molecules such as cyclic AMP (cAMP) and Ca2+. Genetically encoded sensors for cGMP have been developed based on fluorescence resonance energy transfer (FRET) between fluorescent proteins. However, to analyze the dynamic relationship among these second messengers, combined use of existing sensors in a single cell is inadequate because of the significant spectral overlaps. A single wavelength indica...

  2. Activation, binding, and processing of complement component 3 (C3) by Blastomyces dermatitidis.

    OpenAIRE

    Zhang, M X; B. Klein(Ghent University, Ghent, Belgium)

    1997-01-01

    Complement plays a key role in phagocyte recognition and killing of Blastomyces dermatitidis, but little is known about how complement components interact with the yeast. We report the characteristics of activation, binding, and processing of C3 by B. dermatitidis. In pooled normal human serum (NHS), deposition of C3 on the yeast was detectable within 2 min, whereas in NHS containing MgEGTA, deposition was delayed by 6 min, indicating that the yeast activates C3 by both classical and alternat...

  3. The role of complement component C3b and its receptors in sperm-oocyte interaction.

    OpenAIRE

    Anderson, D. J.; Abbott, A F; Jack, R M

    1993-01-01

    Previous studies have shown that human sperm that have undergone the acrosome reaction express a unique tissue-specific variant of the complement component 3 (C3)-binding molecule membrane cofactor protein (MCP, CD46) and that damaged or dead sperm activate the alternative pathway of complement and bind C3 catabolites. In this study we provide evidence that MCP on sperm that have undergone the acrosome reaction specifically binds dimeric C3b and that human sperm acrosomal proteases released d...

  4. Association of the porcine C3 gene with haemolytic complement activity in the pig

    OpenAIRE

    Mekchay, Supamit; Ponsuksili, Siriluck; Schellander, Karl; Wimmers, Klaus

    2003-01-01

    International audience The complement component C3 plays an essential role in the activated complement system, which is involved in phagocytosis, inflammation and immunoregulation to destroy infectious microorganisms. The C3 molecule has more implications in the general defence mechanisms. In this study, the porcine C3 cDNA sequences including $5'$- and $3'$- flanking regions were determined and the polymorphisms in this gene were identified to carry out an association analysis between C3 ...

  5. Complement C1q Activates Tumor Suppressor WWOX to Induce Apoptosis in Prostate Cancer Cells

    OpenAIRE

    Hong, Qunying; Sze, Chun-I; Lin, Sing-Ru; Lee, Ming-Hui; He, Ruei-Yu; Schultz, Lori; Chang, Jean-Yun; Chen, Shean-Jen; Boackle, Robert J; Hsu, Li-Jin; Chang, Nan-Shan

    2009-01-01

    Background Tissue exudates contain low levels of serum complement proteins, and their regulatory effects on prostate cancer progression are largely unknown. We examined specific serum complement components in coordinating the activation of tumor suppressors p53 and WWOX (also named FOR or WOX1) and kinases ERK, JNK1 and STAT3 in human prostate DU145 cells. Methodology/Principal Findings DU145 cells were cultured overnight in 1% normal human serum, or in human serum depleted of an indicated co...

  6. Metonymy as a motivating factor in the system of adjective complementation in English

    OpenAIRE

    Brdar, Mario

    2000-01-01

    The present paper is concerned with demonstrating how various types of metonymic mappings can help motivate (i) the morphosyntactic form and (ii) the semantic content of complements of certain sets of English predicative adjectives, thus eliminating a number of apparent idiosyncracies in the complementation system of English adjectives. Two case studies, one on a marginal possessive construction and the other on predications exhibiting MANNER-FOR-ACTIVITY metonymy, are adduced ...

  7. Sparse approximations of the Schur complement for parallel algebraic hybrid linear solvers in 3D

    OpenAIRE

    Giraud, Luc; Haidar, Azzam; Saad, Yousef

    2010-01-01

    In this report we study the computational performance of variants of an algebraic additive Schwarz preconditioner for the Schur complement for the solution of large sparse linear systems. In earlier works, the local Schur complements were computed exactly using a sparse direct solver. The robustness of the preconditioner comes at the price of this memory and time intensive computation that is the main bottleneck of the approach for tackling huge problems. In this work we investigate the use o...

  8. Mutations in complement regulatory proteins predispose to preeclampsia: a genetic analysis of the PROMISSE cohort.

    Directory of Open Access Journals (Sweden)

    Jane E Salmon

    2011-03-01

    Full Text Available BACKGROUND: Pregnancy in women with systemic lupus erythematosus (SLE or antiphospholipid antibodies (APL Ab--autoimmune conditions characterized by complement-mediated injury--is associated with increased risk of preeclampsia and miscarriage. Our previous studies in mice indicate that complement activation targeted to the placenta drives angiogenic imbalance and placental insufficiency. METHODS AND FINDINGS: We use PROMISSE, a prospective study of 250 pregnant patients with SLE and/or APL Ab, to test the hypothesis in humans that impaired capacity to limit complement activation predisposes to preeclampsia. We sequenced genes encoding three complement regulatory proteins--membrane cofactor protein (MCP, complement factor I (CFI, and complement factor H (CFH--in 40 patients who had preeclampsia and found heterozygous mutations in seven (18%. Five of these patients had risk variants in MCP or CFI that were previously identified in atypical hemolytic uremic syndrome, a disease characterized by endothelial damage. One had a novel mutation in MCP that impairs regulation of C4b. These findings constitute, to our knowledge, the first genetic defects associated with preeclampsia in SLE and/or APL Ab. We confirmed the association of hypomorphic variants of MCP and CFI in a cohort of non-autoimmune preeclampsia patients in which five of 59 were heterozygous for mutations. CONCLUSION: The presence of risk variants in complement regulatory proteins in patients with SLE and/or APL Ab who develop preeclampsia, as well as in preeclampsia patients lacking autoimmune disease, links complement activation to disease pathogenesis and suggests new targets for treatment of this important public health problem. STUDY REGISTRATION: ClinicalTrials.gov NCT00198068.

  9. Complement-Mediated Dysfunction of Glomerular Filtration Barrier Accelerates Progressive Renal Injury

    OpenAIRE

    Abbate, Mauro; Zoja, Carla; Corna, Daniela; Rottoli, Daniela; Zanchi, Cristina; Azzollini, Nadia; Tomasoni, Susanna; Berlingeri, Silvia; Noris, Marina; Morigi, Marina; Remuzzi, Giuseppe

    2008-01-01

    Intrarenal complement activation leads to chronic tubulointerstitial injury in animal models of proteinuric nephropathies, making this process a potential target for therapy. This study investigated whether a C3-mediated pathway promotes renal injury in the protein overload model and whether the abnormal exposure of proximal tubular cells to filtered complement could trigger the resulting inflammatory response. Mice with C3 deficiency were protected to a significant degree against the protein...

  10. Anopheles midgut epithelium evades human complement activity by capturing factor H from the blood meal.

    Directory of Open Access Journals (Sweden)

    Ayman Khattab

    2015-02-01

    Full Text Available Hematophagous vectors strictly require ingesting blood from their hosts to complete their life cycles. Exposure of the alimentary canal of these vectors to the host immune effectors necessitates efficient counteractive measures by hematophagous vectors. The Anopheles mosquito transmitting the malaria parasite is an example of hematophagous vectors that within seconds can ingest human blood double its weight. The innate immune defense mechanisms, like the complement system, in the human blood should thereby immediately react against foreign cells in the mosquito midgut. A prerequisite for complement activation is that the target cells lack complement regulators on their surfaces. In this work, we analyzed whether human complement is active in the mosquito midgut, and how the mosquito midgut cells protect themselves against complement attack. We found that complement remained active for a considerable time and was able to kill microbes within the mosquito midgut. However, the Anopheles mosquito midgut cells were not injured. These cells were found to protect themselves by capturing factor H, the main soluble inhibitor of the alternative complement pathway. Factor H inhibited complement on the midgut cells by promoting inactivation of C3b to iC3b and preventing the activity of the alternative pathway amplification C3 convertase enzyme. An interference of the FH regulatory activity by monoclonal antibodies, carried to the midgut via blood, resulted in increased mosquito mortality and reduced fecundity. By using a ligand blotting assay, a putative mosquito midgut FH receptor could be detected. Thereby, we have identified a novel mechanism whereby mosquitoes can tolerate human blood.

  11. Detection of complement activation using monoclonal antibodies against C3d

    OpenAIRE

    Thurman, Joshua M.; Kulik, Liudmila; Orth, Heather; Wong, Maria; Renner, Brandon; Sargsyan, Siranush A.; Mitchell, Lynne M.; Hourcade, Dennis E.; Hannan, Jonathan P.; Kovacs, James M.; Coughlin, Beth; Woodell, Alex S.; Pickering, Matthew C.; Rohrer, Bärbel; Holers, V. Michael

    2013-01-01

    During complement activation the C3 protein is cleaved, and C3 activation fragments are covalently fixed to tissues. Tissue-bound C3 fragments are a durable biomarker of tissue inflammation, and these fragments have been exploited as addressable binding ligands for targeted therapeutics and diagnostic agents. We have generated cross-reactive murine monoclonal antibodies against human and mouse C3d, the final C3 degradation fragment generated during complement activation. We developed 3 monocl...

  12. Differential complement activation and susceptibility to human serum bactericidal action by Vibrio species.

    OpenAIRE

    1983-01-01

    The ability of Vibrio vulnificus to resist human serum bactericidal action and to activate human complement was compared with similar cultures of Vibrio cholerae and Vibrio parahaemolyticus. Both V. vulnificus and V. parahaemolyticus had similar survival rates in sera and were much more resistant to killing than was V. cholerae. In contrast, V. vulnificus activated significantly less serum complement than did V. cholerae and V. parahaemolyticus. The relative ability of V. vulnificus to surviv...

  13. A preconditioner based on low-rank approximation of Schur complements

    OpenAIRE

    Gatto, Paolo; Hesthaven, Jan S.

    2015-01-01

    We introduce a preconditioner based on a hierarchical low-rank compression scheme of Schur complements. The construction is inspired by standard nested dissection, and relies on the assumption that the Schur complements can be approximated, to high precision, by Hierarchically-Semi-Separable matrices. We build the preconditioner as an approximate $LDM^t$ factorization of a given matrix $A$, and no knowledge of $A$ in assembled form is required by the construction. The $LDM^t$ factorization is...

  14. Inhibition of complement factor C5 protects against renal ischemia-reperfusion injury : Inhibition of late apoptosis and inflammation

    NARCIS (Netherlands)

    De Vries, B; Matthijsen, RA; Wolfs, TGAM; Van Bijnen, AAJHM; Heeringa, P; Buurman, WA

    2003-01-01

    Background Complement has been implicated in the pathophysiology of renal ischemia-reperfusion (I/R) injury. However, the mechanism underlying complement-mediated renal I/R injury is thus far unknown. To investigate the involvement of complement in I/R injury, we studied the activation and depositio

  15. Risk alleles in CFH and ARMS2 are independently associated with systemic complement activation in age-related macular degeneration.

    NARCIS (Netherlands)

    Smailhodzic, D.; Klaver, C.C.; Klevering, B.J.; Boon, C.J.F.; Groenewoud, J.M.M.; Kirchhof, B.; Daha, M.R.; Hollander, A.I. den; Hoyng, C.B.

    2012-01-01

    PURPOSE: Systemic complement activation is associated with age-related macular degeneration (AMD) and has mainly been attributed to a risk allele in the complement factor H (CFH) gene. Whether other important AMD genes also influence complement activation is unclear. In the present case-control stud

  16. Anti-complement activity of the Ixodes scapularis salivary protein Salp20.

    Science.gov (United States)

    Hourcade, Dennis E; Akk, Antonina M; Mitchell, Lynne M; Zhou, Hui-fang; Hauhart, Richard; Pham, Christine T N

    2016-01-01

    Complement, a major component of innate immunity, presents a rapid and robust defense of the intravascular space. While regulatory proteins protect host cells from complement attack, when these measures fail, unrestrained complement activation may trigger self-tissue injury, leading to pathologic conditions. Of the three complement activation pathways, the alternative pathway (AP) in particular has been implicated in numerous disease and injury states. Consequently, the AP components represent attractive targets for therapeutic intervention. The common hard-bodied ticks from the family Ixodidae derive nourishment from the blood of their mammalian hosts. During its blood meal the tick is exposed to host immune effectors, including the complement system. In defense, the tick produces salivary proteins that can inhibit host immune functions. The Salp20 salivary protein of Ixodes scapularis inhibits the host AP pathway by binding properdin and dissociating C3bBbP, the active C3 convertase. In these studies we examined Salp20 activity in various complement-mediated pathologies. Our results indicate that Salp20 can inhibit AP-dependent pathogenesis in the mouse. Its efficacy may be part in due to synergic effects it provides with the endogenous AP regulator, factor H. While Salp20 itself would be expected to be highly immunogenic and therefore inappropriate for therapeutic use, its emergence speaks for the potential development of a non-immunogenic Salp20 mimic that replicates its anti-properdin activity. PMID:26675068

  17. Acute Systolic Heart Failure Associated with Complement-Mediated Hemolytic Uremic Syndrome

    Directory of Open Access Journals (Sweden)

    John L. Vaughn

    2015-01-01

    Full Text Available Complement-mediated hemolytic uremic syndrome (otherwise known as atypical HUS is a rare disorder of uncontrolled complement activation that may be associated with heart failure. We report the case of a 49-year-old female with no history of heart disease who presented with microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury. Given her normal ADAMSTS13 activity, evidence of increased complement activation, and renal biopsy showing evidence of thrombotic microangiopathy, she was diagnosed with complement-mediated HUS. She subsequently developed acute hypoxemic respiratory failure secondary to pulmonary edema requiring intubation and mechanical ventilation. A transthoracic echocardiogram showed evidence of a Takotsubo cardiomyopathy with an estimated left ventricular ejection fraction of 20%, though ischemic cardiomyopathy could not be ruled out. Treatment was initiated with eculizumab. After several failed attempts at extubation, she eventually underwent tracheotomy. She also required hemodialysis to improve her uremia and hypervolemia. After seven weeks of hospitalization and five doses of eculizumab, her renal function and respiratory status improved, and she was discharged in stable condition on room air and independent of hemodialysis. Our case illustrates a rare association between acute systolic heart failure and complement-mediated HUS and highlights the potential of eculizumab in stabilizing even the most critically-ill patients with complement-mediated disease.

  18. The role of complement system in adipose tissue-related inflammation.

    Science.gov (United States)

    Vlaicu, Sonia I; Tatomir, Alexandru; Boodhoo, Dallas; Vesa, Stefan; Mircea, Petru A; Rus, Horea

    2016-06-01

    As the common factor linking adipose tissue to the metabolic context of obesity, insulin resistance and atherosclerosis are associated with a low-grade chronic inflammatory status, to which the complement system is an important contributor. Adipose tissue synthesizes complement proteins and is a target of complement activation. C3a-desArg/acylation-stimulating protein stimulates lipogenesis and affects lipid metabolism. The C3a receptor and C5aR are involved in the development of adipocytes' insulin resistance through macrophage infiltration and the activation of adipose tissue. The terminal complement pathway has been found to be instrumental in promoting hyperglycemia-associated tissue damage, which is characteristic of the major vascular complications of diabetes mellitus and diabetic ketoacidosis. As a mediator of the effects of the terminal complement complex C5b-9, RGC-32 has an impact on energy expenditure as well as lipid and glucose metabolic homeostasis. All of this evidence, taken together, indicates an important role for complement activation in metabolic diseases. PMID:26754764

  19. Complement-related proteins control the flavivirus infection of Aedes aegypti by inducing antimicrobial peptides.

    Directory of Open Access Journals (Sweden)

    Xiaoping Xiao

    2014-04-01

    Full Text Available The complement system functions during the early phase of infection and directly mediates pathogen elimination. The recent identification of complement-like factors in arthropods indicates that this system shares common ancestry in vertebrates and invertebrates as an immune defense mechanism. Thioester (TE-containing proteins (TEPs, which show high similarity to mammalian complement C3, are thought to play a key role in innate immunity in arthropods. Herein, we report that a viral recognition cascade composed of two complement-related proteins limits the flaviviral infection of Aedes aegypti. An A. aegypti macroglobulin complement-related factor (AaMCR, belonging to the insect TEP family, is a crucial effector in opposing the flaviviral infection of A. aegypti. However, AaMCR does not directly interact with DENV, and its antiviral effect requires an A. aegypti homologue of scavenger receptor-C (AaSR-C, which interacts with DENV and AaMCR simultaneously in vitro and in vivo. Furthermore, recognition of DENV by the AaSR-C/AaMCR axis regulates the expression of antimicrobial peptides (AMPs, which exerts potent anti-DENV activity. Our results both demonstrate the existence of a viral recognition pathway that controls the flaviviral infection by inducing AMPs and offer insights into a previously unappreciated antiviral function of the complement-like system in arthropods.

  20. Inhibition of the alternative complement pathway preserves photoreceptors after retinal injury.

    Science.gov (United States)

    Sweigard, J Harry; Matsumoto, Hidetaka; Smith, Kaylee E; Kim, Leo A; Paschalis, Eleftherios I; Okonuki, Yoko; Castillejos, Alexandra; Kataoka, Keiko; Hasegawa, Eiichi; Yanai, Ryoji; Husain, Deeba; Lambris, John D; Vavvas, Demetrios; Miller, Joan W; Connor, Kip M

    2015-07-22

    Degeneration of photoreceptors is a primary cause of vision loss worldwide, making the underlying mechanisms surrounding photoreceptor cell death critical to developing new treatment strategies. Retinal detachment, characterized by the separation of photoreceptors from the underlying retinal pigment epithelium, is a sight-threatening event that can happen in a number of retinal diseases. The detached photoreceptors undergo apoptosis and programmed necrosis. Given that photoreceptors are nondividing cells, their loss leads to irreversible visual impairment even after successful retinal reattachment surgery. To better understand the underlying disease mechanisms, we analyzed innate immune system regulators in the vitreous of human patients with retinal detachment and correlated the results with findings in a mouse model of retinal detachment. We identified the alternative complement pathway as promoting early photoreceptor cell death during retinal detachment. Photoreceptors down-regulate membrane-bound inhibitors of complement, allowing for selective targeting by the alternative complement pathway. When photoreceptors in the detached retina were removed from the primary source of oxygen and nutrients (choroidal vascular bed), the retina became hypoxic, leading to an up-regulation of complement factor B, a key mediator of the alternative pathway. Inhibition of the alternative complement pathway in knockout mice or through pharmacological means ameliorated photoreceptor cell death during retinal detachment. Our current study begins to outline the mechanism by which the alternative complement pathway facilitates photoreceptor cell death in the damaged retina. PMID:26203084

  1. Effect of Sex Differences on Complement Activation System in Patients with Acute Myocardial Infarction; Evaluation of the Effects of Streptokinase on Complement System

    International Nuclear Information System (INIS)

    Whether and to what extent complement is activated, what is the sex difference, what its possible relation to coronary reperfusion in patients with acute myocardial infarction (AMI) whether treated or not with Streptokinase (SK) and how it contributes to inflammation of the ischemic area are not yet clear. This study was to evaluate the difference between complement activation in males and females in patients with AMI and to measure the extent of complement activation in AMI patients, some treated with SK and some untreated due to medical conditions prevent the use of SK. In addition, because abrupt complement activation in vivo is usually associated with leukocyte margination, plugging of cells in the microcirculation, we correlated complement activation with leukocyte numbers. Blood pressure (BP) was also assessed during SK treatment; the lowest value of the systolic BP (SBP) recorded ten minutes before SK infusion was considered the baseline value. This study was carried out on 47 patients with AMI (27 males and 20 females); 28patients were treated with SK (had no contraindications to SK) and 19 were not given any fibrinolytic agents; the extent and severity of AMI were not significantly different in both groups. Twenty healthy volunteers, age and sex matched (10 males and 10 females) served as controls. Blood samples were collected on arrival at the hospital from all volunteers, and in those groups treated with SK, blood samples were drawn at 15, 120 minutes during SK infusion and 24 hours later. Time-matched samples were also collected from patients SK untreated and control groups. Caa, C4a, and SCsb-9 and leukocytes were measured in each blood sample. Arterial blood pressure was evaluated during SK-infusion. This study verified no significant differences between males and females

  2. Complement factor D homolog involved in the alternative complement pathway of rock bream (Oplegnathus fasciatus): Molecular and functional characterization and immune responsive mRNA expression analysis.

    Science.gov (United States)

    Godahewa, G I; Perera, N C N; Bathige, S D N K; Nam, Bo-Hye; Noh, Jae Koo; Lee, Jehee

    2016-08-01

    The complement system serves conventional role in the innate defense against common invading pathogens. Complement factor D (CfD) is vital to alternative complement pathway activation in cleaving complement factor B. This catalytic reaction forms the alternative C3 convertase that is crucial for complement-mediated pathogenesis. In this study, rock bream (Oplegnathus fasciatus) CfD (OfCfD) was characterized and OfCfD mRNA expression was investigated. OfCfD encodes 277 amino acids (aa) for a 30-kDa polypeptide. A domain analysis of the deduced OfCfD aa sequence showed a single serine protease trypsin superfamily domain, a serine active region, three active sites, and three substrate-binding sites. Pairwise sequence comparisons indicated that OfCfD has the highest identity (84.5%) with Oreochromis niloticus CfD. The phylogenetic tree revealed a common ancestral origin of CfD members, with fish CfD distinct from other vertebrate orthologs. The structural arrangement of the OfCfD gene (2451 bp) contained five exons interrupted by four introns. A spatial transcriptional analysis indicated that OfCfD transcripts constitutively expressed in all of the examined rock bream tissues, and that they were highest in the spleen and liver. In addition, OfCfD transcripts were immunologically upregulated by lipopolysaccharide (LPS) (12 h p.i.), Streptococcus iniae (12 h p.i.), rock bream iridovirus (RBIV) (6-12 h p.i.), and poly I:C (6 h p.i.) in spleen tissue. OfCfD is a trypsin protease and its recombinant protein showed strong protease activity similar to that of trypsin, indicating its catalytic function in the alternative pathway. Together, our findings suggest that OfCfD might be involved in immune responses in rock bream. PMID:27311435

  3. Fabrication and imaging study of ultrasound/fluorescence bi-modal contrast agent based on polymeric microbubbles

    International Nuclear Information System (INIS)

    based on polymeric microbubbles has been successfully fabricated for the use of ultrasound and fluorescence imaging. It retains the good characteristics of both echogenicity and fluorescence, which complement each other in case of limitations imposed by uni-modal, single agents. (authors)

  4. Instructive for disposal of fluorescent

    International Nuclear Information System (INIS)

    An instructive is established for the management system of waste fluorescent lamps, ensuring the storage, collection, transportation, and final disposal. The lamp is changed by an official of the Seccion de Matenimiento Construccion of the Oficina de Servicios Generales or is produced with the support of an official of the unit. The fluorescent should be deposited in stock of materials of the building maintenance section or unit specified with the help of a staff and in appropriate conditions. The fluorescent lamp is transported according to the guidelines in the manual. A responsible company is contracted by la Vicerrectoria de Administracion of the Universidad de Costa Rica dedicated to the transport and proper handling of fluorescent lamps

  5. X-ray fluorescence holography

    CERN Document Server

    Hayashi, K; Takahashi, Y

    2003-01-01

    X-ray fluorescence holography (XFH) is a new structural analysis method of determining a 3D atomic arrangement around fluorescing atoms. We developed an XFH apparatus using advanced X-ray techniques and succeeded in obtaining high-quality hologram data. Furthermore, we introduced applications to the structural analysis of a thin film and the environment around dopants and, discussed the quantitative analysis of local lattice distortion. (author)

  6. A NEW METHOD TO ASSESS FUNCTIONAL ACTIVITY OF SERUM COMPLEMENT SYSTEM

    Directory of Open Access Journals (Sweden)

    E. G. Cheremnykh

    2015-01-01

    Full Text Available Complement system is an important component of innate immunity, providing primary protection against pathogens invading the body. In addition, it was shown that the complement system is associated with many diseases, not only autoimmune and infectious, but also mental disorders. In this regard, it is necessary to develop affordable and fast method of measuring activity of the complement system in real-time mode. We present a new semi-automated method for assessment of serum complement activity. The assay is based on cytolytic action of complement system upon the ciliate organism Tetrahymena pyriformis. This method consists in repeated counting of live Tetrahymena motile cells by means of specially developed Biolat device, which consists of two video cameras, light sources, and movable round plate. The plate has two rows of holes. The device also includes microprocessor control unit based on AutoCiliata software, intended for control of operation module and counting the surviving cell. The calculations are based on fixation of two sequential video-frames, with subsequent software image processing. Cell death events were observed upon incubation in triethanolamine (TEA buffer containing 5% of blood serum. We have also compared complement activity in different buffers, i.e., standard medium for culturing of ciliates, Veronal-Medinalum buffer, and the TEA buffer. TEA buffer was found superior to the Veronal buffer when applied in the test system. The time of cell death in the TEA-buffered medium containing 5% serum was < 15 minutes for all the sera studied. The parameters denoting serum complement activity were as follows: a half-life time for the moving cells (TLD50, and a similar value for 100% cell inactivation (1/TLD50, functional activity of the complement system, ACS. The sensitivity of this assay was calculated from dependencies between TLD50 and ACS, and actual serum concentrations. We have suggested an opportunity for evaluation of an

  7. A new treatment for neurogenic inflammation caused by EV71 with CR2-targeted complement inhibitor

    Directory of Open Access Journals (Sweden)

    Qiu Shaofu

    2012-11-01

    Full Text Available Abstract Background Enterovirus 71 (EV71, one of the most important neurotropic EVs, has caused death and long-term neurological sequelae in hundreds of thousands of young children in the Asia-Pacific region in the past decade. The neurological diseases are attributed to infection by EV71 inducing an extensive peripheral and central nervous system (CNS inflammatory response with abnormal cytokine production and lymphocyte depletion induced by EV71 infection. In the absence of specific antiviral agents or vaccines, an effective immunosuppressive strategy would be valuable to alleviate the severity of the local inflammation induced by EV71 infection. Presentation of the hypothesis The complement system plays a pivotal role in the inflammatory response. Inappropriate or excessive activation of the complement system results in a severe inflammatory reaction or numerous pathological injuries. Previous studies have revealed that EV71 infection can induce complement activation and an inflammatory response of the CNS. CR2-targeted complement inhibition has been proved to be a potential therapeutic strategy for many diseases, such as influenza virus-induced lung tissue injury, postischemic cerebral injury and spinal cord injury. In this paper, a mouse model is proposed to test whether a recombinant fusion protein consisting of CR2 and a region of Crry (CR2-Crry is able to specifically inhibit the local complement activation induced by EV71 infection, and to observe whether this treatment strategy can alleviate or even cure the neurogenic inflammation. Testing the hypothesis CR2-Crry is expressed in CHO cells, and its biological activity is determined by complement inhibition assays. 7-day-old ICR mice are inoculated intracranially with EV71 to duplicate the neurological symptoms. The mice are then divided into two groups, in one of which the mice are treated with CR2-Crry targeted complement inhibitor, and in the other with phosphate-buffered saline. A

  8. Expression of complement system components during aging and amyloid deposition in APP transgenic mice

    Directory of Open Access Journals (Sweden)

    Wiederhold Karl-Heinz

    2009-11-01

    Full Text Available Abstract Background A causal role of the complement system in Alzheimer's disease pathogenesis has been postulated based on the identification of different activated components up to the membrane attack complex at amyloid plaques in brain. However, histological studies of amyloid plaque bearing APP transgenic mice provided only evidence for an activation of the early parts of the complement cascade. To better understand the contribution of normal aging and amyloid deposition to the increase in complement activation we performed a detailed characterization of the expression of the major mouse complement components. Methods APP23 mice expressing human APP751 with the Swedish double mutation as well as C57BL/6 mice were used at different ages. mRNA was quantified by Realtime PCR and the age- as well as amyloid induced changes determined. The protein levels of complement C1q and C3 were analysed by Western blotting. Histology was done to test for amyloid plaque association and activation of the complement cascade. Results High mRNA levels were detected for C1q and some inhibitory complement components. The expression of most activating components starting at C3 was low. Expression of C1q, C3, C4, C5 and factor B mRNA increased with age in control C57BL/6 mice. C1q and C3 mRNA showed a substantial additional elevation during amyloid formation in APP23 mice. This increase was confirmed on the protein level using Western blotting, whereas immunohistology indicated a recruitment of complement to amyloid plaques up to the C3 convertase. Conclusion Early but not late components of the mouse complement system show an age-dependent increase in expression. The response to amyloid deposition is comparatively smaller. The low expression of C3 and C5 and failure to upregulate C5 and downstream components differs from human AD brain and likely contributes to the lack of full complement activation in APP transgenic mice.

  9. The Two Sides of Complement C3d: Evolution of Electrostatics in a Link between Innate and Adaptive Immunity

    OpenAIRE

    Kieslich, Chris A.; Dimitrios Morikis

    2012-01-01

    The interaction between complement fragment C3d and complement receptor 2 (CR2) is a key aspect of complement immune system activation, and is a component in a link between innate and adaptive immunities. The complement immune system is an ancient mechanism for defense, and can be found in species that have been on Earth for the last 600 million years. However, the link between the complement system and adaptive immunity, which is formed through the association of the B-cell co-receptor compl...

  10. Fluorescent retroreflective signing of work zones : abstract

    NARCIS (Netherlands)

    Vos, A.P. de; Horst, A.R.A. van der; Alferdinck, J.W.A.M.; Kooi, F.L.

    1999-01-01

    Fluorescent retroreflective materials increase the brightness of traffic signs. In construction work zones a benefit is expected from the increased conspicuity of fluorescent retroreflective signs. Fluorescent material can be used instead of non-fluorescent materials both for the advance warning sig

  11. 21 CFR 892.1220 - Fluorescent scanner.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Fluorescent scanner. 892.1220 Section 892.1220...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1220 Fluorescent scanner. (a) Identification. A fluorescent scanner is a device intended to measure the induced fluorescent radiation in the body by...

  12. Complement System in the Pathogenesis of Benign Lymphoepithelial Lesions of the Lacrimal Gland.

    Directory of Open Access Journals (Sweden)

    Jing Li

    Full Text Available We aimed to examine the potential involvement of local complement system gene expression in the pathogenesis of benign lymphoepithelial lesions (BLEL of the lacrimal gland.We collected data from 9 consecutive pathologically confirmed patients with BLEL of the lacrimal gland and 9 cases with orbital cavernous hemangioma as a control group, and adopted whole genome microarray to screen complement system-related differential genes, followed by RT-PCR verification and in-depth enrichment analysis (Gene Ontology analysis of the gene sets.The expression of 14 complement system-related genes in the pathologic tissue, including C2, C3, ITGB2, CR2, C1QB, CR1, ITGAX, CFP, C1QA, C4B|C4A, FANCA, C1QC, C3AR1 and CFHR4, were significantly upregulated while 7 other complement system-related genes, C5, CFI, CFHR1|CFH, CFH, CD55, CR1L and CFD were significantly downregulated in the lacrimal glands of BLEL patients. The microarray results were consistent with RT-PCR analysis results. Immunohistochemistry analysis of C3c and C1q complement component proteins in the resected tissue were positive in BLEL patients, while the control group had negative expression of these proteins. Gene ontology (GO analysis revealed that activation of the genes of complement system-mediated signaling pathways were the most enriched differential gene group in BLEL patients.Local expression of complement components is prominently abnormal in BLEL, and may well play a role in its pathogenesis.

  13. Host Specificity of Ovine Bordetella parapertussis and the Role of Complement.

    Directory of Open Access Journals (Sweden)

    Sara E Hester

    Full Text Available The classical bordetellae are comprised of three subspecies that differ from broad to very limited host specificity. Although several lineages appear to have specialized to particular host species, most retain the ability to colonize and grow in mice, providing a powerful common experimental model to study their differences. One of the subspecies, Bordetella parapertussis, is composed of two distinct clades that have specialized to different hosts: one to humans (Bpphu, and the other to sheep (Bppov. While Bpphu and the other classical bordetellae can efficiently colonize mice, Bppov strains are severely defective in their ability to colonize the murine respiratory tract. Bppov genomic analysis did not reveal the loss of adherence genes, but substantial mutations and deletions of multiple genes involved in the production of O-antigen, which is required to prevent complement deposition on B. bronchiseptica and Bpphu strains. Bppov lacks O-antigen and, like O-antigen mutants of other bordetellae, is highly sensitive to murine complement-mediated killing in vitro. Based on these results, we hypothesized that Bppov failed to colonize mice because of its sensitivity to murine complement. Consistent with this, the Bppov defect in the colonization of wild type mice was not observed in mice lacking the central complement component C3. Furthermore, Bppov strains were highly susceptible to killing by murine complement, but not by sheep complement. These data demonstrate that the failure of Bppov to colonize mice is due to sensitivity to murine, but not sheep, complement, providing a mechanistic example of how specialization that accompanies expansion in one host can limit host range.

  14. Bordetella pertussis acquires resistance to complement-mediated killing in vivo.

    Science.gov (United States)

    Pishko, Elizabeth J; Betting, David J; Hutter, Christina S; Harvill, Eric T

    2003-09-01

    In order to initially colonize a host, bacteria must avoid various components of the innate immune system, one of which is complement. The genus Bordetella includes three closely related species that differ in their ability to resist complement-mediated killing. Bordetella parapertussis and Bordetella bronchiseptica resist killing in naïve serum, a characteristic that may aid in efficient respiratory tract colonization and has been attributed to expression of O antigen. Bordetella pertussis lacks O antigen and is sensitive to naïve serum in vitro, yet it also efficiently colonizes the respiratory tract. Based on these observations, we hypothesized that B. pertussis may have an alternate mechanism to resist complement in vivo. While a number of reports on serum sensitivity of the bordetellae have been published, we show here that serum concentration and growth conditions can greatly alter the observed level of sensitivity to complement and that all but one strain of B. pertussis observed were sensitive to some level of naïve serum in vitro, particularly when there was excess complement. However, B. pertussis rapidly acquires increased resistance in vivo to naïve serum that is specific to the alternative pathway. Resistance is not efficiently acquired by B. parapertussis and B. bronchiseptica mutants lacking O antigen. This B. pertussis-specific mechanism of complement resistance does not appear to be dependent on either brkA or other genes expressed specifically in the Bvg(+) phase. This in vivo acquisition of alternative pathway resistance suggests that there is a novel O antigen-independent method by which B. pertussis evades complement-mediated killing. PMID:12933835

  15. Human pentraxin 3 binds to the complement regulator c4b-binding protein.

    Directory of Open Access Journals (Sweden)

    Anne Braunschweig

    Full Text Available The long pentraxin 3 (PTX3 is a soluble recognition molecule with multiple functions including innate immune defense against certain microbes and the clearance of apoptotic cells. PTX3 interacts with recognition molecules of the classical and lectin complement pathways and thus initiates complement activation. In addition, binding of PTX3 to the alternative complement pathway regulator factor H was shown. Here, we show that PTX3 binds to the classical and lectin pathway regulator C4b-binding protein (C4BP. A PTX3-binding site was identified within short consensus repeats 1-3 of the C4BP α-chain. PTX3 did not interfere with the cofactor activity of C4BP in the fluid phase and C4BP maintained its complement regulatory activity when bound to PTX3 on surfaces. While C4BP and factor H did not compete for PTX3 binding, the interaction of C4BP with PTX3 was inhibited by C1q and by L-ficolin. PTX3 bound to human fibroblast- and endothelial cell-derived extracellular matrices and recruited functionally active C4BP to these surfaces. Whereas PTX3 enhanced the activation of the classical/lectin pathway and caused enhanced C3 deposition on extracellular matrix, deposition of terminal pathway components and the generation of the inflammatory mediator C5a were not increased. Furthermore, PTX3 enhanced the binding of C4BP to late apoptotic cells, which resulted in an increased rate of inactivation of cell surface bound C4b and a reduction in the deposition of C5b-9. Thus, in addition to complement activators, PTX3 interacts with complement inhibitors including C4BP. This balanced interaction on extracellular matrix and on apoptotic cells may prevent excessive local complement activation that would otherwise lead to inflammation and host tissue damage.

  16. Complement inhibitors from scabies mites promote streptococcal growth--a novel mechanism in infected epidermis?

    Directory of Open Access Journals (Sweden)

    Angela Mika

    Full Text Available BACKGROUND: Scabies is highly prevalent in socially disadvantaged communities such as indigenous populations and in developing countries. Generalized itching causes discomfort to the patient; however, serious complications can occur as a result of secondary bacterial pyoderma, commonly caused by Streptococcus pyogenes (GAS or Staphylococcus aureus. In the tropics, skin damage due to scabies mite infestations has been postulated to be an important link in the pathogenesis of disease associated with acute rheumatic fever and heart disease, poststreptococcal glomerulonephritis and systemic sepsis. Treatment of scabies decreases the prevalence of infections by bacteria. This study aims to identify the molecular mechanisms underlying the link between scabies and GAS infections. METHODOLOGY/PRINCIPAL FINDINGS: GAS bacteria were pre-incubated with blood containing active complement, phagocytes and antibodies against the bacteria, and subsequently tested for viability by plate counts. Initial experiments were done with serum from an individual previously exposed to GAS with naturally acquired anti-GAS antibodies. The protocol was optimized for large-scale testing of low-opsonic whole blood from non-exposed human donors by supplementing with a standard dose of heat inactivated human sera previously exposed to GAS. This allowed an extension of the dataset to two additional donors and four proteins tested at a range of concentrations. Shown first is the effect of scabies mite complement inhibitors on human complement using ELISA-based complement activation assays. Six purified recombinant mite proteins tested at a concentration of 50 µg/ml blocked all three complement activation pathways. Further we demonstrate in human whole blood assays that each of four scabies mite complement inhibitors tested increased GAS survival rates by 2-15 fold. CONCLUSIONS/SIGNIFICANCE: We propose that local complement inhibition plays an important role in the development of

  17. Complement Inhibition for Prevention and Treatment of Antibody-Mediated Rejection in Renal Allograft Recipients.

    Science.gov (United States)

    Jordan, S C; Choi, J; Kahwaji, J; Vo, A

    2016-04-01

    Therapeutic interventions aimed at the human complement system are recognized as potentially important strategies for the treatment of inflammatory and autoimmune diseases because there is often evidence of complement-mediated injury according to pathologic assessments. In addition, there are a large number of potential targets, both soluble and cell bound, that might offer potential for new drug development, but progress in this area has met with significant challenges. Currently, 2 drugs are approved aimed at inhibition of complement activation. The first option is eculizumab (anti-C5), which is approved for the treatment of paroxysmal nocturnal hemoglobinuria and atypical hemolytic uremic syndrome. Eculizumab has also been studied in human transplantation for the treatment and prevention of antibody-mediated rejection (ABMR). Initial data from uncontrolled studies suggested a significant benefit of eculizumab for the prevention of ABMR in highly HLA-sensitized patients, but a subsequent randomized, placebo-controlled trial failed to meet its primary endpoint. Anecdotal data, primarily from case studies, showed benefits in treating complement-mediated ABMR. A second approved complement-inhibiting therapy is C1 esterase inhibitor (C1-INH), which is approved for use in patients with hereditary angioedema, a condition caused by mutations in the gene that codes for C1-INH. A recent placebo-controlled trial of C1-INH for prevention of ABMR in HLA-sensitized patients found that the drug was safe, with evidence for inhibition of systemic complement activation and complement-activating donor-specific antibodies. Other drugs are now under development. PMID:27234741

  18. Distinct CD55 Isoform Synthesis and Inhibition of Complement-Dependent Cytolysis by Hepatitis C Virus.

    Science.gov (United States)

    Kwon, Young-Chan; Kim, Hangeun; Meyer, Keith; Di Bisceglie, Adrian M; Ray, Ranjit

    2016-08-15

    CD55/DAF, one of the regulators of complement activation, is known to limit excess complement activation on the host cell surface by accelerating the decay of C3 convertase. We reported previously that hepatitis C virus (HCV) infection or virus core protein expression upregulates CD55 expression. CD55 associates with HCV particles, potentially protecting HCV from lysis in circulation. An increase in CD55 on the surface of HCV-infected cells may inhibit complement-mediated cell killing. In this study, we show that Abs against cancer cell surface proteins induce complement-dependent cytolysis or Ab-dependent cell-mediated cytotoxicity of immortalized human hepatocytes in the presence of CD55-blocking Ab. CD55 has a secreted isoform (sCD55) that is generated by alternative splicing. We observed that sCD55 is induced in HCV-infected or HCV replicon-harboring cells, as well as in liver biopsy samples from chronically HCV-infected patients. Conditioned medium from HCV-infected hepatoma cells (Huh7.5 cells) or immortalized human hepatocytes inhibited C3 convertase activity and complement-dependent cytolysis of sheep blood erythrocytes. Chronically HCV-infected patient sera inhibited C3 convertase activity, further implicating HCV-specific impairment of complement function in infected humans. CD55-blocking Ab inhibited erythrocyte lysis by conditioned medium, suggesting that CD55/sCD55 impairs convertase activity. Together, our data show that HCV infection induces sCD55 expression in HCV-infected cell culture-conditioned medium and inhibits C3 convertase activity. This may have implications for modulating complement-mediated immune function in the microenvironment and on HCV-harboring cells. PMID:27357152

  19. Investigation of Quenching Mechanism in Thermoreversible Fluorescent Recording Materials of Fluorescence Using Thermochromic Fluorescence Resonance Energy Transfer

    Science.gov (United States)

    Shuzo Hirata,; Martin Vacha,; Toshiyuki Watanabe,

    2010-05-01

    We demonstrated reversible thermosensitive recording of a fluorescent image (TRF) using a low-molecular-weight mixture consisting of a fluorescent dye, a fluoran dye, a developer, and a reversible matrix. In this material, reversible thermoresponsive disorder-crystal transition triggers a cyclical colorless-color change of a fluoran dye, which induces on-off switching of fluorescence resonance energy transfer (FRET) from a fluorescent dye to a fluoran dye. On-off switching of fluorescence is induced by heat-promoted off-on switching of FRET. Modulation of fluorescence is held at room temperature by utilizing thermal hysteresis, and nondestructive readout of the fluorescent image is accomplished in the presence of excitation light. Here, we investigate the on-off switching mechanism of fluorescence in this recording material. We analyzed the theoretical factor of emission quenching in the erasing state by comparing the theoretical overlap integral Ω between fluorescent dyes and fluoran dyes on the basis of the FRET theory with experimental emission contrast for various combinations of fluorescent dyes and fluoran dyes. It was proved that fluorescence on-off switching occurs mainly by concentration quenching due to the aggregation of fluorescent dyes and FRET from isolated fluorescent dyes to colored fluoran dyes. The key issue to obtain both high-contrast fluorescence and high fluorescence quantum yield is to control these two factors.

  20. Chlorophyll fluorescence emission spectrum inside a leaf

    OpenAIRE

    Pedrós Esteban, Roberto; Moya, Ismael; Goulas, Yves; Jacquemoud, Stéphane

    2008-01-01

    Chlorophyll a fluorescence can be used as an early stress indicator. Fluorescence is also connected to photosynthesis so it can be proposed for global monitoring of vegetation status from a satellite platform. Nevertheless, the correct interpretation of fluorescence requires accurate physical models. The spectral shape of the leaf fluorescence free of any re-absorption effect plays a key role in the models and is difficult to measure. We present a vegetation fluorescence emission spectrum fre...

  1. Metal-enhanced fluorescence of single green fluorescent protein (GFP)

    International Nuclear Information System (INIS)

    The green fluorescent protein (GFP) has emerged as a powerful reporter molecule for monitoring gene expression, protein localization, and protein-protein interaction. However, the detection of low concentrations of GFPs is limited by the weakness of the fluorescent signal and the low photostability. In this report, we observed the proximity of single GFPs to metallic silver nanoparticles increases its fluorescence intensity approximately 6-fold and decreases the decay time. Single protein molecules on the silvered surfaces emitted 10-fold more photons as compared to glass prior to photobleaching. The photostability of single GFP has increased to some extent. Accordingly, we observed longer duration time and suppressed blinking. The single-molecule lifetime histograms indicate the relatively heterogeneous distributions of protein mutants inside the structure

  2. Solution Structures of Complement C2 and Its C4 Complexes Propose Pathway-specific Mechanisms for Control and Activation of the Complement Proconvertases.

    Science.gov (United States)

    Mortensen, Sofia; Jensen, Jan K; Andersen, Gregers R

    2016-08-01

    The lectin (LP) and classical (CP) pathways are two of the three main activation cascades of the complement system. These pathways start with recognition of different pathogen- or danger-associated molecular patterns and include identical steps of proteolytic activation of complement component C4, formation of the C3 proconvertase C4b2, followed by cleavage of complement component C2 within C4b2 resulting in the C3 convertase C4b2a. Here, we describe the solution structures of the two central complexes of the pathways, C3 proconvertase and C3 convertase, as well as the unbound zymogen C2 obtained by small angle x-ray scattering analysis. We analyzed both native and enzymatically deglycosylated C4b2 and C2 and showed that the resulting structural models were independent of the glycans. The small angle x-ray scattering-derived models suggest a different activation mode for the CP/LP C3 proconvertase as compared with that established for the alternative pathway proconvertase C3bB. This is likely due to the rather different structural and functional properties of the proteases activating the proconvertases. The solution structure of a stabilized form of the active CP/LP C3 convertase C4b2a is strikingly similar to the crystal structure of the alternative pathway C3 convertase C3bBb, which is in accordance with their identical functions in cleaving the complement proteins C3 and C5. PMID:27252379

  3. The Embryotrophic Activity of Oviductal Cell-derived Complement C3b and iC3b, a Novel Function of Complement Protein in Reproduction

    OpenAIRE

    Lee, YL; Lee, KF; Lee, WM; Luk, JM; Yeung, WSB; Xu, JS; He, QY; Chiu, JF

    2004-01-01

    The oviduct-derived embryotrophic factor, ETF-3, enhances the development of trophectoderm and the hatching process of treated embryos. Monoclonal anti-ETF-3 antibody that abolishes the embryotrophic activity of ETF-3 recognized a 115-kDa protein from the conditioned medium of immortalized human oviductal cells. Mass spectrometry analysis showed that the protein was complement C3. Western blot analysis using an antibody against C3 confirmed the cross-reactivities between anti-C3 antibody with...

  4. Complementation of a DNA repair defect in xeroderma pigmentosum cells by transfer of human chromosome 9

    International Nuclear Information System (INIS)

    Complementation of the repair defect in xeroderma pigmentosum cells of complementation group A was achieved by the transfer of human chromosome 9. A set of mouse-human hybrid cell lines, each containing a single Ecogpt-marked human chromosome, was used as a source of donor chromosomes. Chromosome transfer to XPTG-1 cells, a hypoxanthine/guanine phosphoribosyltransferase-deficient mutant of simian virus 40-transformed complementation group A cells, was achieved by microcell fusion and selection for Ecogpt. Chromosome-transfer clones of XPTG-1 cells, each containing a different human donor chromosome, were analyzed for complementation of sensitivity to UV irradiation. Among all the clones, increased levels of resistance to UV was observed only in clones containing chromosome 9. Since our recipient cell line XPTG-1 is hypoxanthine/guanine phosphoribosyltransferase deficient, cultivation of Ecogpt+ clones in medium containing 6-thioguanine permits selection of cells for loss of the marker and, by inference, transferred chromosome 9. Clones isolated for growth in 6-thioguanine, which have lost the Ecogpt-marked chromosome, exhibited a UV-sensitive phenotype, confirming the presence of the repair gene(s) for complementation group A on chromosome 9

  5. Postoperative Atypical Hemolytic Uremic Syndrome Associated with Complement C3 Mutation

    Directory of Open Access Journals (Sweden)

    Eiji Matsukuma

    2014-01-01

    Full Text Available Atypical hemolytic uremic syndrome (aHUS can be distinguished from typical or Shiga-like toxin-induced HUS. The clinical outcome is unfavorable; up to 50% of affected patients progress to end-stage renal failure and 25% die during the acute phase. Multiple conditions have been associated with aHUS, including infections, drugs, autoimmune conditions, transplantation, pregnancy, and metabolic conditions. aHUS in the nontransplant postsurgical period, however, is rare. An 8-month-old boy underwent surgical repair of tetralogy of Fallot. Neurological disturbances, acute renal failure, thrombocytopenia, and microangiopathic hemolytic anemia developed 25 days later, and aHUS was diagnosed. Further evaluation revealed that his complement factor H (CFH level was normal and that anti-FH antibodies were not detected in his plasma. Sequencing of his CFH, complement factor I, membrane cofactor protein, complement factor B, and thrombomodulin genes was normal. His ADAMTS-13 (a disintegrin-like and metalloprotease with thrombospondin-1 repeats 13 activity was also normal. However, he had a potentially causative mutation (R425C in complement component C3. Restriction fragment length polymorphism analysis revealed that his father and aunt also had this mutation; however, they had no symptoms of aHUS. We herein report a case of aHUS that developed after cardiovascular surgery and was caused by a complement C3 mutation.

  6. Association of the porcine C3 gene with haemolytic complement activity in the pig

    Directory of Open Access Journals (Sweden)

    Mekchay Supamit

    2003-06-01

    Full Text Available Abstract The complement component C3 plays an essential role in the activated complement system, which is involved in phagocytosis, inflammation and immunoregulation to destroy infectious microorganisms. The C3 molecule has more implications in the general defence mechanisms. In this study, the porcine C3 cDNA sequences including 5'- and 3'- flanking regions were determined and the polymorphisms in this gene were identified to carry out an association analysis between C3 and complement activity traits. Porcine C3 gene has high homology with human C3. Five single nucleotide polymorphisms (SNPs and one microsatellite were detected in the porcine C3 gene. Haemolytic complement activity of alternative and classical pathways (ACH, CCP was measured in 416 F2 animals of a crossbred of Duroc × Berlin Miniature Pig, which were immunized with Mycoplasma, Aujeszky and PRRS vaccines. C3 markers were found to be significantly associated (P C3 with complement activity reinforces the importance of C3 as a candidate gene for natural resistance to microorganisms.

  7. Postoperative atypical hemolytic uremic syndrome associated with complement c3 mutation.

    Science.gov (United States)

    Matsukuma, Eiji; Imamura, Atsushi; Iwata, Yusuke; Takeuchi, Takamasa; Yoshida, Yoko; Fujimura, Yoshihiro; Fan, Xinping; Miyata, Toshiyuki; Kuwahara, Takashi

    2014-01-01

    Atypical hemolytic uremic syndrome (aHUS) can be distinguished from typical or Shiga-like toxin-induced HUS. The clinical outcome is unfavorable; up to 50% of affected patients progress to end-stage renal failure and 25% die during the acute phase. Multiple conditions have been associated with aHUS, including infections, drugs, autoimmune conditions, transplantation, pregnancy, and metabolic conditions. aHUS in the nontransplant postsurgical period, however, is rare. An 8-month-old boy underwent surgical repair of tetralogy of Fallot. Neurological disturbances, acute renal failure, thrombocytopenia, and microangiopathic hemolytic anemia developed 25 days later, and aHUS was diagnosed. Further evaluation revealed that his complement factor H (CFH) level was normal and that anti-FH antibodies were not detected in his plasma. Sequencing of his CFH, complement factor I, membrane cofactor protein, complement factor B, and thrombomodulin genes was normal. His ADAMTS-13 (a disintegrin-like and metalloprotease with thrombospondin-1 repeats 13) activity was also normal. However, he had a potentially causative mutation (R425C) in complement component C3. Restriction fragment length polymorphism analysis revealed that his father and aunt also had this mutation; however, they had no symptoms of aHUS. We herein report a case of aHUS that developed after cardiovascular surgery and was caused by a complement C3 mutation. PMID:25431709

  8. The complement system and toll-like receptors as integrated players in the pathophysiology of atherosclerosis.

    Science.gov (United States)

    Hovland, Anders; Jonasson, Lena; Garred, Peter; Yndestad, Arne; Aukrust, Pål; Lappegård, Knut T; Espevik, Terje; Mollnes, Tom E

    2015-08-01

    Despite recent medical advances, atherosclerosis is a global burden accounting for numerous deaths and hospital admissions. Immune-mediated inflammation is a major component of the atherosclerotic process, but earlier research focus on adaptive immunity has gradually switched towards the role of innate immunity. The complement system and toll-like receptors (TLRs), and the crosstalk between them, may be of particular interest both with respect to pathogenesis and as therapeutic targets in atherosclerosis. Animal studies indicate that inhibition of C3a and C5a reduces atherosclerosis. In humans modified LDL-cholesterol activate complement and TLRs leading to downstream inflammation, and histopathological studies indicate that the innate immune system is present in atherosclerotic lesions. Moreover, clinical studies have demonstrated that both complement and TLRs are upregulated in atherosclerotic diseases, although interventional trials have this far been disappointing. However, based on recent research showing an intimate interplay between complement and TLRs we propose a model in which combined inhibition of both complement and TLRs may represent a potent anti-inflammatory therapeutic approach to reduce atherosclerosis. PMID:26086357

  9. Genetic variations in complement factors in patients with congenital thrombotic thrombocytopenic purpura with renal insufficiency.

    Science.gov (United States)

    Fan, Xinping; Kremer Hovinga, Johanna A; Shirotani-Ikejima, Hiroko; Eura, Yuka; Hirai, Hidenori; Honda, Shigenori; Kokame, Koichi; Taleghani, Magnus Mansouri; von Krogh, Anne-Sophie; Yoshida, Yoko; Fujimura, Yoshihiro; Lämmle, Bernhard; Miyata, Toshiyuki

    2016-03-01

    The congenital form of thrombotic thrombocytopenic purpura (TTP) is caused by genetic mutations in ADAMTS13. Some, but not all, congenital TTP patients manifest renal insufficiency in addition to microangiopathic hemolysis and thrombocytopenia. We included 32 congenital TTP patients in the present study, which was designed to assess whether congenital TTP patients with renal insufficiency have predisposing mutations in complement regulatory genes, as found in many patients with atypical hemolytic uremic syndrome (aHUS). In 13 patients with severe renal insufficiency, six candidate complement or complement regulatory genes were sequenced and 11 missense mutations were identified. One of these missense mutations, C3:p.K155Q mutation, is a rare mutation located in the macroglobulin-like 2 domain of C3, where other mutations predisposing for aHUS cluster. Several of the common missense mutations identified in our study have been reported to increase disease-risk for aHUS, but were not more common in patients with as compared to those without renal insufficiency. Taken together, our results show that the majority of the congenital TTP patients with renal insufficiency studied do not carry rare genetic mutations in complement or complement regulatory genes. PMID:26830967

  10. Complement-opsonized HIV: the free rider on its way to infection.

    Science.gov (United States)

    Stoiber, Heribert; Pruenster, Monika; Ammann, Christoph G; Dierich, Manfred P

    2005-02-01

    The complement system (C) is one of the main humoral components of innate immunity. Three major tasks of C against invading pathogens are: (i) lysis of pathogens by the formation of the membrane attack complex (MAC); (ii) opsonization of pathogens with complement fragments to favor phagocytosis; and (iii) attraction of inflammatory cells by chemotaxis. Like other particles, HIV activates C and becomes opsonized. To escape complement-mediated lysis, HIV has adopted various properties, which include the acquisition of HIV-associated molecules (HAMs) belonging to the family of complement regulators, such as CD46, CD55, CD59, and the interaction with humoral regulatory factors like factor H (fH). Opsonized virus may bind to complement receptor positive cells to infect them more efficiently or to remain bound on the surface of such cells. In the latter case HIV can be transmitted to cells susceptible for infection. This review discusses several aspects of C-HIV interactions and provides a model for the dynamics of this process. PMID:15488605

  11. Mechanisms of evasion of Schistosoma mansoni schistosomula to the lethal activity of complement

    Directory of Open Access Journals (Sweden)

    F. Juarez Ramalho-Pinto

    1992-01-01

    Full Text Available Schistosomula of Schistosoma mansoni became resistant to antibody-dependent complement damage in vitro after pre-incubation with normal human erythrocytes (NHuE whatever the ABO or Rh blood group. Resistant parasites were shown to acquire host decay accelerating factor (DAF , a 70 kDa glycoprotein attached to the membrane of NHue by a GPI anchor. IgG2a mAb anti-human DAF (IA10 immunoprecipitated a 70 kDa molecule from 125I-labeled schistosomula pre-incubated with NHuE and inhibited their resistance to complement-dependent killing in vtro. Incubationof schistosomula with erytrocytes from patients with paroxsimal nocturnal hemoglobinuria (PNHE or SRBC, wich are DAF-deficient, did not protect the parasites from complement lesion. Supernatant of 100,000 x g collected from NHuE incubated for 24 h in defined medium was shown to contain a soluble form of DAF and to protect schistosomula from complement killing. Schistosomula treated with trypsin before incubation with NHuE ghosts did not become resistant to complement damage. On the other hand, pre-treatment with chymotrypsin did not interfere with the acquisition of resistance by the schistosomula. These results indicate that, in vitro, NHuE DAF can be transferred to schistosomula in a soluble form and that the binding of this molecule to the parasite surface is dependent upon trypsin-sensitive chymotrypsin-insensitive polipeptide(s present on the surface of the worm.

  12. The relationship between complement factor C3, APOE ε4, amyloid and tau in Alzheimer's disease.

    Science.gov (United States)

    Bonham, Luke W; Desikan, Rahul S; Yokoyama, Jennifer S

    2016-01-01

    Inflammation is becoming increasingly recognized as an important contributor to Alzheimer's disease (AD) pathogenesis. As a part of the innate immune system, the complement cascade enhances the body's ability to destroy and remove pathogens and has recently been shown to influence Alzheimer's associated amyloid and tau pathology. However, little is known in humans about the effects of the complement system and genetic modifiers of AD risk like the ε4 allele of apolioprotein E (APOE ε4) on AD pathobiology. We evaluated cerebrospinal fluid (CSF) protein levels from 267 individuals clinically diagnosed as cognitively normal, mild cognitive impairment, and AD. Using linear models, we assessed the relationship between APOE ε4 genotype, CSF Complement 3 (C3), CSF amyloid-β (amyloid) and CSF hyperphosphorylated tau (ptau). We found a significant interaction between APOE ε4 and CSF C3 on both CSF amyloid and CSF ptau. We also found that CSF C3 is only associated with CSF ptau after accounting for CSF amyloid. Our results support a conceptual model of the AD pathogenic cascade where a synergistic relationship between the complement cascade (C3) and APOE ε4 results in elevated Alzheimer's neurodegeneration and in turn, amyloid further regulates the effect of the complement cascade on downstream tau pathology. PMID:27357286

  13. Understanding bimolecular machines: Theoretical and experimental approaches

    Science.gov (United States)

    Goler, Adam Scott

    This dissertation concerns the study of two classes of molecular machines from a physical perspective: enzymes and membrane proteins. Though the functions of these classes of proteins are different, they each represent important test-beds from which new understanding can be developed by the application of different techniques. HIV1 Reverse Transcriptase is an enzyme that performs multiple functions, including reverse transcription of RNA into an RNA/DNA duplex, RNA degradation by the RNaseH domain, and synthesis of dsDNA. These functions allow for the incorporation of the retroviral genes into the host genome. Its catalytic cycle requires repeated large-scale conformational changes fundamental to its mechanism. Motivated by experimental work, these motions were studied theoretically by the application of normal mode analysis. It was observed that the lowest order modes correlate with largest amplitude (low-frequency) motion, which are most likely to be catalytically relevant. Comparisons between normal modes obtained via an elastic network model to those calculated from the essential dynamics of a series of all-atom molecular dynamics simulations show the self-consistency between these calculations. That similar conformational motions are seen between independent theoretical methods reinforces the importance of large-scale subdomain motion for the biochemical action of DNA polymerases in general. Moreover, it was observed that the major subunits of HIV1 Reverse Transcriptase interact quasi-harmonically. The 5HT3A Serotonin receptor and P2X1 receptor, by contrast, are trans-membrane proteins that function as ligand gated ion channels. Such proteins feature a central pore, which allows for the transit of ions necessary for cellular function across a membrane. The pore is opened by the ligation of binding sites on the extracellular portion of different protein subunits. In an attempt to resolve the individual subunits of these membrane proteins beyond the diffraction limit, a super-localization microscope capable of reconstructing super-resolution images was constructed. This novel setup allows for the study of discrete state kinetic mechanisms with spatial resolution good enough to distinguish individual binding sites of these membrane proteins. Further use of this technique may allow for the study of allostery and subunit specific stoichiometry in the presence of agonist or antagonist ligands relevant to pharmacology.

  14. Fluorescent Ribozyme and Deoxyribozyme Sensors

    Science.gov (United States)

    Chiuman, William; Li, Yingfu

    The development of allosteric nucleic acid enzymes (NAEs) has made NAEs very attractive for a wide variety of biotechnological applications, including biosensing, diagnostics, drug screening, and molecular computation. Although NAEs alone might have limited values for analytical application due to the rather small scope of their substrates and cofactors, modular characteristics of aptamers and NAEs permit the easy design of combined sensors where the aptamer acts as the molecular recognition element (MRE) and the NAE functions as a reporter. To facilitate the exploitation of NAEs for biosensing applications, fluorescence methods have been increasingly explored as better alternatives to radioisotope-based detection techniques. In this chapter, we first survey the strategies that have been employed to graft fluorescence-signaling moieties onto NAEs. We then review our experimental efforts in creating a group of fluorescence-signaling and RNA-cleaving deoxyribozymes (DNAzymes) intended for the design of fluorescent sensors. Last, we discuss the diverse engineering approaches that can transmit the binding status of an aptamer to the activation or repression of catalytic activity in fluorescent NAE sensors.

  15. Fluorescence and phosphorescence of rutin

    Energy Technology Data Exchange (ETDEWEB)

    Bondarev, Stanislav L., E-mail: bondarev@imaph.bas-net.by [Minsk State Higher Radioengineering College, 220005 Minsk (Belarus); Knyukshto, Valeri N. [B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, 220072 Minsk (Belarus)

    2013-10-15

    Rutin is one of the most promising flavonoid from a pharmacological and biochemical point of view. Here we have explored its spectroscopic and photophysical properties at room temperature and 77 K using steady-state absorption-luminescence methods and pulse spectroscopy equipment. By excitation into the absorption band 1 of rutin in methanol at room temperature the normal Stokes' shifted fluorescence with a maximum at 415 nm and quantum yield of 2×10{sup −4} was revealed. However, by excitation into the bands 2 and 3 any emission wasn’t observed. At 77 K in ethanol glass we have observed fluorescence at 410 nm and phosphorescence at 540 nm for the first time. As a result the adequate energetic scheme including the lowest electronic excited singlet at 26000 cm{sup −1} and triplet at 19600 cm{sup −1} states was proposed. -- Highlights: • Rutin fluorescence and phosphorescence at 77 K were revealed for the first time. • Room temperature fluorescence is determined by maximum at 415 nm and yield of 2×10{sup −4}. • Violation of Vavilov–Kasha rule by excitation into the absorption bands 2 and 3. • Fluorescence and phosphorescence in rutin are caused by the allowed π, π{sup (⁎)} transitions.

  16. Fluorescence and optical absorption in spodumene

    International Nuclear Information System (INIS)

    This work studied the mechanism of the isothermal decay's kinetic of the 15.600 cm-1 optical absorption band (A.O.) of irradiated spodumene, and the phosphorescence of irradiated spodumene in low temperatures. The kinetic mechanisms applying the bimolecular model to liberation, capture and recombination reactions are analysed. The coupled differential equations, resultants of this model, numerically using the Runge-Kutta method is solved, and a computer programs that allowed determine the kinetics parameters by try and error methods is developped. This work showed that the electrons are untrapped according to Arrhernios kinetic and that the parameters of the trap and recombination are proportional to a factor (√T - √To ), where To is the cutting temperature, bfore which the reactions do not occur. (author)

  17. Effect of SOS of enterobacteria on their interaction with the complement system

    International Nuclear Information System (INIS)

    Adaptation of bacteria in the human and animal body is closely linked with changes in activity of the immune defense systems. An important component of the latter is complement. One of the first defense responses of the host to microbial invasion is considered to be activation of proteins of the complement system via an alternative path, which does not require the participation of antibodies, by direct interaction of component C3 with elements of the bacterial surface. The aim of this paper was to study the role of the recA gene in interaction between enterobacteria and serum complement during activation of the alternative path. The percentage of the component C3 hydrolyzed was determined by measuring the quantity of C3a fragment formed using the immunoblotting method and monoclonal labelled iodine 125-anti-C3a immunoglobulins specific for both the native C3 molecule and for its small C3a fragment

  18. Complement factor H deficiency results in decreased neuroretinal expression of Cd59a in aged mice

    DEFF Research Database (Denmark)

    Faber, Carsten; Williams, Jennifer; Juel, Helene Bæk; Greenwood, John; Nissen, Mogens Holst; Moss, Stephen E.

    2012-01-01

    changes in the function of CFH influence development of AMD are unclear, we examined ocular complement expression as a consequence of age in control and CFH null mutant mice. Methods. Gene expression in neuroretinas and RPE/choroid from young and aged WT and Cfh−/− C57BL/6J mice was analyzed by...... microarrays. Expression of a wide range of complement genes was compared with expression in liver. Results. An age-associated increased expression of complement, particularly C1q, C3, and factor B, in the RPE/choroid coincided with increased expression of the negative regulators Cfh and Cd59a in the...... neuroretina. Young mice deficient in CFH expressed Cd59a similar to WT, but failed to upregulate Cd59a expression with age. Hepatic expression of Cd59a increased with age regardless of Cfh genotype. Conclusions. While the connection between CFH deficiency and failure to upregulate CD59a remains unknown, these...

  19. Interplay Between Amphioxus Complement with Sea Bass Macrophages: Opsonic Activity of Amphioxus Humoral Fluids

    Institute of Scientific and Technical Information of China (English)

    PAN Junli; LIU Min; ZHANG Shicui

    2011-01-01

    Previous studies have shown the existence of a complement system in the amphioxus Branchiostoma japonicum.However,whether it has an opsonic activity similar to that of vertebrates remains unknown.We demonstrated that the humoral fluid (HF)of amphioxus promoted the phagocytosis of yeast cells with sea bass (Lateolabraxjaponicus) macrophages,whereas the C3-depleted and heated HF significantly lost the phagocytosis-promoting capacity.In addition,the precipitation of factor B (Bf) led to a marked loss of opsonic activity.Moreover,C3 fragments in the HF were found to bind to yeast cell surfaces.The results indicate that the amphioxus complement system is an important element involved in the opsonic activity,which promotes the sea bass macrophage phagocytosis by tagging yeast cells with C3 fragments via the activation of alternative complement pathway.

  20. Complement Factor H Serum Levels Determine Resistance to Pneumococcal Invasive Disease.

    Science.gov (United States)

    van der Maten, Erika; Westra, Dineke; van Selm, Saskia; Langereis, Jeroen D; Bootsma, Hester J; van Opzeeland, Fred J H; de Groot, Ronald; Ruseva, Marieta M; Pickering, Matthew C; van den Heuvel, Lambert P W J; van de Kar, Nicole C A J; de Jonge, Marien I; van der Flier, Michiel

    2016-06-01

    Streptococcus pneumoniae is a major cause of life-threatening infections. Complement activation plays a vital role in opsonophagocytic killing of pneumococci in blood. Initial complement activation via the classical and lectin pathways is amplified through the alternative pathway amplification loop. Alternative pathway activity is inhibited by complement factor H (FH). Our study demonstrates the functional consequences of the variability in human serum FH levels on host defense. Using an in vivo mouse model combined with human in vitro assays, we show that the level of serum FH correlates with the efficacy of opsonophagocytic killing of pneumococci. In summary, we found that FH levels determine a delicate balance of alternative pathway activity, thus affecting the resistance to invasive pneumococcal disease. Our results suggest that variation in FH expression levels, naturally occurring in the human population, plays a thus far unrecognized role in the resistance to invasive pneumococcal disease. PMID:26802141