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Artigos de revistas sobre o assunto "Antigens Analysis Molecular aspects"
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Mulloy, Barbara, e Ten Feizi. "Tricks of the trade in glycoscience: The preparation and analysis of a blood group A-active mucin glycoprotein". Biochemist 36, n.º 4 (1 de agosto de 2014): 18–20. http://dx.doi.org/10.1042/bio03604018.
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Many aspects of glycosylation are conserved among animals, and it can be advantageous and sometimes critical to identify a readily available and abundant source of carbohydrate material that harbours a hard-to-characterize antigen or ligand of interest. The Biochemical Journal Classic paper by Morgan and King is a well-written account of serviceable methods for the extraction and quantification of a carbohydrate antigen. These methods were highly influential in subsequent studies of the blood group antigens. Some of these tricks of the trade still have a place in modern glycobiology.
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De Masi, Luigi, Maria Antonia Argenio, Deborah Giordano e Angelo Facchiano. "Molecular Aspects of Spike–ACE2 Interaction". Encyclopedia 2, n.º 1 (10 de janeiro de 2022): 96–108. http://dx.doi.org/10.3390/encyclopedia2010007.
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A new betacoronavirus (CoV-2) is responsible for the pandemic of severe acute respiratory syndrome (SARS) that began in China at the end of 2019, today known as COronaVIrus Disease 2019 (COVID-19). Subsequent studies confirmed the human angiotensin-converting enzyme 2 (hACE2) as the main cell receptor of spike trimeric glycoprotein, located on the viral envelope, mediating the CoV-2 invasion into the host cells through the receptor-binding domain (RBD) of the spike. Computational analysis of the known experimental 3D structures of spike–ACE2 complexes evidenced distinguishing features in the molecular interactions at the RBD-cell receptor binding interface between CoV-2 and previous CoV-1. The spike represents a key target for drug design as well as an optimal antigen for RNA/viral vector vaccines and monoclonal antibodies in order to maximize prevention and therapy of COVID-19.
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van der Zee, J. S., P. van Swieten e R. C. Aalberse. "Serologic aspects of IgG4 antibodies. II. IgG4 antibodies form small, nonprecipitating immune complexes due to functional monovalency." Journal of Immunology 137, n.º 11 (1 de dezembro de 1986): 3566–71. http://dx.doi.org/10.4049/jimmunol.137.11.3566.
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Abstract Human IgG4 antibodies directed against phospholipase A, the P1 antigen from Dermatophagoïdes pteronyssinus extracts, and cat albumin were found unable to cross-link antigen. Previously, it was demonstrated that IgG4 antibodies, in contrast to IgG1 antibodies, did not cross-link Sepharose-bound antigen and antigen added in solution. To eliminate the possibility that this phenomenon was caused by preferential binding of both IgG4 Fab fragments to the solid-phase-bound antigen, cross-linking of antigen was studied in a fluid-phase system. In this test, incapability of IgG4 antibodies to bridge two antigens was also found. As a result of such a phenomenon, it is expected that immune complexes formed by IgG4 antibodies will be considerably smaller than complexes formed by IgG1. This was confirmed by analysis of the molecular size profiles of IgG1- and IgG4-containing immune complexes in sucrose-density gradients. Moreover, IgG1 was able to precipitate antigen in a radioimmunoprecipitation test, whereas precipitation was not demonstrable by the same amount of IgG4 antibodies. Even 3% polyethylene glycol 8,000 did not precipitate the small IgG4-containing immune complexes efficiently. The antibodies studied were of a high-affinity type, and there was no significant difference in association constants between IgG1 and IgG4 antibodies. Therefore, we were not able to confirm observations reported in the literature that the IgG4 subclass is associated with a low-affinity antibody response; probably, the affinity of the IgG4 antibodies was underestimated by other investigators because of the polyethylene glycol precipitation technique used to separate antibody-bound and free antigen. Our findings stress the point that IgG4 antibodies take a special place in the immune response upon chronic exposure to antigen.
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Bräunlein, Eva, Gaia Lupoli, Franziska Füchsl, Esam T. Abualrous, Niklas de Andrade Krätzig, Dario Gosmann, Lukas Wietbrock et al. "Functional analysis of peripheral and intratumoral neoantigen-specific TCRs identified in a patient with melanoma". Journal for ImmunoTherapy of Cancer 9, n.º 9 (setembro de 2021): e002754. http://dx.doi.org/10.1136/jitc-2021-002754.
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BackgroundNeoantigens derived from somatic mutations correlate with therapeutic responses mediated by treatment with immune checkpoint inhibitors. Neoantigens are therefore highly attractive targets for the development of therapeutic approaches in personalized medicine, although many aspects of their quality and associated immune responses are not yet well understood. In a case study of metastatic malignant melanoma, we aimed to perform an in-depth characterization of neoantigens and respective T-cell responses in the context of immune checkpoint modulation.MethodsThree neoantigens, which we identified either by immunopeptidomics or in silico prediction, were investigated using binding affinity analyses and structural simulations. We isolated seven T-cell receptors (TCRs) from the patient’s immune repertoire recognizing these antigens. TCRs were compared in vitro by multiparametric analyses including functional avidity, multicytokine secretion, and cross-reactivity screenings. A xenograft mouse model served to study in vivo functionality of selected TCRs. We investigated the patient’s TCR repertoire in blood and different tumor-related tissues over 3 years using TCR beta deep sequencing.ResultsSelected mutated peptide ligands with proven immunogenicity showed similar binding affinities to the human leukocyte antigen complex and comparable disparity to their wild-type counterparts in molecular dynamic simulations. Nevertheless, isolated TCRs recognizing these antigens demonstrated distinct patterns in functionality and frequency. TCRs with lower functional avidity showed at least equal antitumor immune responses in vivo. Moreover, they occurred at high frequencies and particularly demonstrated long-term persistence within tumor tissues, lymph nodes and various blood samples associated with a reduced activation pattern on primary in vitro stimulation.ConclusionsWe performed a so far unique fine characterization of neoantigen-specific T-cell responses revealing defined reactivity patterns of neoantigen-specific TCRs. Our data highlight qualitative differences of these TCRs associated with function and longevity of respective T cells. Such features need to be considered for further optimization of neoantigen targeting including adoptive T-cell therapies using TCR-transgenic T cells.
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Makhneva, Nataliya V., Yu S. Butov e V. Yu Vasenova. "THE MOLECULAR BIOLOGICAL AND IMMUNE PATHOLOGIC CHARACTERISTICS UNDER AUTO-IMMUNE DISEASES OF SKIN". Medical Journal of the Russian Federation 23, n.º 5 (15 de outubro de 2017): 258–62. http://dx.doi.org/10.18821/0869-2106-2017-23-5-258-262.
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The skin and mucous membranes are the min barrier organs providing systemic defense from environmental effects. They actively participate in deliverance of organism from antigens of various origin due to availability of one's own elements of immune system. The failure in chain of immune defense causes deceleration of process of elimination of antigen damaging structure of one's own tissue. The article presents mechanism of elimination of immune complexes and examples of therapeutic procedures accelerating and normalizing this process. The maintenance and recovery of excretory function of skin ensure positive dynamics of clinical manifestations of various diseases, including ones of autoimmune genesis. In case of fixation of immunoglobulins in tissues, skin acts as a target-organ. At that, detected specific antibodies are diagnostic markers for a wide circle of autoimmune dermatoses. Furthermore, immunopathologic processes occurring in skin are associated with disorders of synthesis of various molecular compounds of its tissue structures. This is testified by the results of immune morphologic picture of expression of a number of molecules of adhesion, protein components of desmosomal apparatus and basal membrane of epidermis, antigens of HLA-system. Therefore, skin is a complex organized structure capable to actively participate in development of inflammatory and autoimmune reactions. The analysis of these reactions at molecular biological level permits to evaluate intensity of occurring processes, to implement testing of efficacy of applied curative activities and in a number of cases to serve as an additional diagnostic marker. Undoubtedly, implementation of molecular biological methods as a tool of cognition favors continuous broadening of information about a number of aspects of pathogenesis of skin diseases and brings to development of new methods of their treatment at the molecular genetic level.
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Buscaglia, Carlos A., Julieta Alfonso, Oscar Campetella e Alberto C. C. Frasch. "Tandem Amino Acid Repeats From Trypanosoma cruzi Shed Antigens Increase the Half-Life of Proteins in Blood". Blood 93, n.º 6 (15 de março de 1999): 2025–32. http://dx.doi.org/10.1182/blood.v93.6.2025.406k19_2025_2032.
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Proteins containing amino acid repeats are widespread among protozoan parasites. It has been suggested that these repetitive structures act as immunomodulators, but other functional aspects may be of primary importance. We have recently suggested that tandem repeats present in Trypanosoma cruzi trans-sialidase stabilize the catalytic activity in blood. Because the parasite releasestrans-sialidase, this delayed clearance of the enzyme might have implications in vivo. In the present work, the ability of repetitive units from different T. cruzi molecules in stabilizing trans-sialidase activity in blood was evaluated. It is shown that repeats present on T. cruzi shed proteins (antigens 13 and Shed-Acute-Phase-Antigen [SAPA]) increase trans-sialidase half-life in blood from 7 to almost 35 hours. Conversely, those repeats present in intracellular T. cruzi proteins only increase the enzyme half-life in blood up to 15 hours. Despite these results, comparative analysis of structural and catalytic properties of both groups of chimeric enzymes show no substantial differences. Interestingly, antigens 13 and SAPA also increase the persistence in blood of chimeric glutathione S-transferases, thus suggesting that this effect is inherent to these repeats and independent of the carrier protein. Although the molecular basis of this phenomenon is still uncertain, its biotechnological potential can be envisaged.
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Udintseva, I. N., O. Ye Chechina, N. G. Zhoukova, L. V. Lukashova, N. V. Ryazantseva, A. M. Poponina, L. A. Malysheva, N. N. Bartfeld e S. A. Pershina. "Clinical immunological aspects of tick-borne encephalitis". Bulletin of Siberian Medicine 7, n.º 5-2 (30 de dezembro de 2008): 438–43. http://dx.doi.org/10.20538/1682-0363-2008-5-2-438-443.
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In this article results of the clinical-immunological analysis with different forms tick-borne encephalitis of Tomsk Region during the period from 2000 to 2008 are represented. The revealled disbalance of cytokines alongside with breach of the expressions cytokines's receptor by limphocytes's cells, can be one of the main of the reasons to inefficiency answer when introducing the infectious agent in organism and shaping the chronic form to infectious pathology, in particular, with long presence of the antigen of the virus tick-borne encephalitis in blood. The trend to increase the level sick with long presence of the antigen of the virus tick-borne encephalitis in blood, with prevalence of the persons feminine flap, mainly average and senior age for the last years is given.
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BILIC, I., M. LEBERL e M. HESS. "Identification and molecular characterization of numerous Histomonas meleagridis proteins using a cDNA library". Parasitology 136, n.º 4 (21 de janeiro de 2009): 379–91. http://dx.doi.org/10.1017/s0031182008005477.
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SUMMARYHistomonas meleagridis is a protozoan parasite of various galliform birds causing a type of enterohepatitis termed histomonosis or ‘blackhead disease’. Due to the ban of chemotherapeutic substances and an increase in free-range poultry production, histomonosis is currently a re-emerging disease. So far limited molecular knowledge is available. In the present work, mRNAs coding for antigenic proteins of H. meleagridis were identified. For this purpose, a cDNA expression library was constructed from a mono-eukaryotic culture of H. meleagridis. The library was screened with polyclonal rabbit serum raised against purified H. meleagridis trophozoites. Polyclonal rabbit serum specifically recognized the same major H. meleagridis antigens as chicken and turkey sera originating from animal trials, but displayed a significantly lower bacteria-dependent background signal. After 2 rounds of screening, a total of 95 positive clones were sequenced. Bioinformatics analyses were performed on nucleotide and deduced amino acid sequences, identifying 37 unique clones. Based on the homology to other protozoan parasites, mostly Trichomonas vaginalis, the clones were grouped according to functional aspects: structural proteins, possible surface proteins, oxygen reducing proteins, ribosomal proteins, protein kinases and various other intracellular proteins.
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Hui, Winnie W., Lisa E. Emerson, Beata Clapp, Austin E. Sheppe, Jatin Sharma, Johanna del Castillo, Mark Ou et al. "Antigen-encapsulating host extracellular vesicles derived from Salmonella-infected cells stimulate pathogen-specific Th1-type responses in vivo". PLOS Pathogens 17, n.º 5 (6 de maio de 2021): e1009465. http://dx.doi.org/10.1371/journal.ppat.1009465.
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Salmonella Typhimurium is a causative agent of nontyphoidal salmonellosis, for which there is a lack of a clinically approved vaccine in humans. As an intracellular pathogen, Salmonella impacts many cellular pathways. However, the intercellular communication mechanism facilitated by host-derived small extracellular vesicles (EVs), such as exosomes, is an overlooked aspect of the host responses to this infection. We used a comprehensive proteome-based network analysis of exosomes derived from Salmonella-infected macrophages to identify host molecules that are trafficked via these EVs. This analysis predicted that the host-derived small EVs generated during macrophage infection stimulate macrophages and promote activation of T helper 1 (Th1) cells. We identified that exosomes generated during infection contain Salmonella proteins, including unique antigens previously shown to stimulate protective immune responses against Salmonella in murine studies. Furthermore, we showed that host EVs formed upon infection stimulate a mucosal immune response against Salmonella infection when delivered intranasally to BALB/c mice, a route of antigen administration known to initiate mucosal immunity. Specifically, the administration of these vesicles to animals stimulated the production of anti-Salmonella IgG antibodies, such as anti-OmpA antibodies. Exosomes also stimulated antigen-specific cell-mediated immunity. In particular, splenic mononuclear cells isolated from mice administered with exosomes derived from Salmonella-infected antigen-presenting cells increased CD4+ T cells secreting Th1-type cytokines in response to Salmonella antigens. These results demonstrate that small EVs, formed during infection, contribute to Th1 cell bias in the anti-Salmonella responses. Collectively, this study helps to unravel the role of host-derived small EVs as vehicles transmitting antigens to induce Th1-type immunity against Gram-negative bacteria. Understanding the EV-mediated defense mechanisms will allow the development of future approaches to combat bacterial infections.
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Fu, Jie, Lenong Li e Marlene Bouvier. "Modulation of MHC class I antigen presentation by the adenovirus E3-19K protein (100.8)". Journal of Immunology 186, n.º 1_Supplement (1 de abril de 2011): 100.8. http://dx.doi.org/10.4049/jimmunol.186.supp.100.8.
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Abstract The presentation of viral antigens by MHC I to CTLs is vital for elimination of infected cells. In turn, viruses have evolved various strategies to abrogate antiviral cellular immune responses. For example, the adenovirus (Ad) E3-19K protein retains MHC I in the endoplasmic reticulum, dramatically suppressing the cell-surface presentation of viral antigens. Many aspects of how E3-19K exerts its function towards MHC I are poorly understood. This knowledge is important as the E3-19K/MHC I interaction is thought to play a role in enabling Ads to cause persistent infections. We characterized biophysically and cellularly interaction between E3-19K proteins of different Ad serotypes (Ad 7 and 35, subgroup B; Ad 2 and Ad 5, subgroup C; Ad 37, subgroup D; and Ad 4, subgroup E) and HLA-A, -B, and -C molecules. Our results show that E3-19K proteins from Ad serotypes of the same subgroup display more similar binding properties for a given MHC I than those of different subgroups. Furthermore, E3-19K proteins exhibited allele- and locus-specificity; higher avidity for HLA-A relative to -B molecules, and no interaction with HLA-C molecules. FACS analysis showed that binding affinities correlated (in a negative way) with levels of MHC I expression on infected cells. Finally, we propose the first model of interaction between E3-19K and MHC I. Overall, our studies provide novel insights into the structure/function relationship of E3-19K and the molecular cell biology of antigen presentation.
Teses / dissertações sobre o assunto "Antigens Analysis Molecular aspects"
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Bianco-Miotto, Tina. "Loss of ABO antigens in haematological malignancies / Tina Bianco-Miotto". Thesis, Adelaide, S.A, 2002. http://hdl.handle.net/2440/21857.
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"May 2002"Includes bibliographical references (leaves 229-251)
xv, 251 leaves : ill. (some col.) ; 30 cm.
Describes the investigation of the alteration of ABH antigen expression on the surface of red blood cells in patients with haematological malignancies.
Thesis (Ph.D.)--University of Adelaide, Dept. of Medicine, 2003
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Bianco-Miotto, Tina. "Loss of ABO antigens in haematological malignancies". Adelaide, S.A, 2002. http://web4.library.adelaide.edu.au/theses/09PH/09phb578.pdf.
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"May 2002" Includes bibliographical references (leaves 229-251) Describes the investigation of the alteration of ABH antigen expression on the surface of red blood cells in patients with haematological malignancies.
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Adeleye, Tolulope Abiodun. "A molecular analysis of the immunological response to mycobacterial antigens". Thesis, University College London (University of London), 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304066.
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Davenport, Miles Philip. "Molecular analysis of HLA associations with infectious disease". Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297073.
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Nath, Deepa. "cDNA sequence analysis of macrophage molecules". Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240654.
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Shipman, Robert Charles. "The molecular characterization of a common human myelogenous leukemia-associated antigen (CAMAL)". Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/27530.
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Previous studies had demonstrated the presence of the p70 (CAMAL) molecule in human myeloid leukemia cells and the promyelocytic leukemia cell line HL60, but not in equivalent preparations of normal cells (Malcolm et al., 1982, 1984; Shipman et al., 1983; Logan et al., 1984). Subsequent studies demonstrated that the p70 (CAMAL) protein was detectable and expressed in human myeloid leukemia cells and the leukemic cell lines HL60, KG1, K562 and U937. The association of p70 (CAMAL) expression with human myeloid leukemia cells prompted its consideration as a candidate leukemia-associated antigen.
The demonstration, following CAMAL purification and peptide sequencing, that two tryptic peptides (tp27, tp31) displayed significant homology to sequences present in human serum albumin (HSA) and human alpha-1-fetoprotein (AFP), while one tryptic peptide (tp20) displayed unique peptide sequence, suggested that CAMAL might represent a protein that was structurally and functionally related to the albumins. Consequently, a comparative biochemical analysis of CAMAL and HSA was initiated.
The results of the comparative studies demonstrated that although CAMAL and HSA shared conformational antigenic determinants, both proteins were also shown to be distinct molecules by a number of other criteria. The possibility that the CAMAL preparation, used for protein sequencing and comparative studies, was contaminated with HSA was thought likely, in view of the HSA/AFP-related peptide sequences from the CAMAL tryptic peptide sequence analysis. However, other results, particularly the antibody reactivity and ligand binding studies, showed that the CAMAL preparation was not contaminated with HSA. The unique CAMAL tryptic peptide (tp20) sequence supported further the contention that CAMAL was a distinct protein with regions homologous to HSA and AFP.
Further analysis of the CAMAL molecule, through extensive protein sequencing, will be, in all likelihood, the only means by which to establish the degree of relatedness between CAMAL, HSA and AFP.Science, Faculty of
Microbiology and Immunology, Department of
Graduate
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Purins, Leanne Roslyn. "Molecular characterisation of the transcriptional activator, HLYU, of Vibrio cholerae O1 /". Title page, abstract and table of contents only, 2004. http://web4.library.adelaide.edu.au/theses/09PH/09php9857.pdf.
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Thesis (Ph.D.)--University of Adelaide, School of Molecular and Biomedical Science , Discipline of Microbiology and Immunology, 2005."May, 2004" Includes corrigenda. includes bibliographical references (leaves 118-156).
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Wright, Andrew. "Molecular analysis of the human antibody response to antigens of Staphylococcus aureus". Thesis, University of Sheffield, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.485077.
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Staphylococcus aureus is a significant cause of Gram-positive sepsis and infection in the nosocomial environment, and has given rise to the MRSA 'superbug'. The identification of multi-drug resistant strains of S. aureus has advanced the search for new targets for S. aureus prophylaxis or therapy. Such strategies may include the identification of novel S. aureus vaccine candidates, or the production of antibodies to appropriate S. aureus antigens for passive immunization. Previous studies have identified antibodies specific to the major cell wall antigen peptidoglycan as important in the opsonisation of S. aureus, facilitating uptake into phagocytic cells and removal from the host. In agreement with others, our studies have shown antibodies to peptidoglycan and its derivatives are present throughout the population over a wide concentration range and are found in sera from both 'normal' control donors and S. aureus infected individuals. In an attempt to dissect the antibody response to peptidoglycan at the molecular level we have created recombinant human single-chain antibody libraries from the genetic material of such donors, and have screened them for the presence of peptidoglycan specific antibodies. Despite extensive analysis and optimisation of'the library construction and screening process, we were unable to isolate such antibodies from our libraries. However, analysis of a large 'singlepot' synthetic library of antibody variable region genes did lead to the retrieval of two antibodies specific for cellosyl-digested S. aureus peptidoglycan. These antibodies were characterised with respect to antigen binding sensitivity and specificity. This study has also focused on the immune response to CHIPS (the chemotaxis inhibitory protein of Staphylococcus aureus), a recently identified virulence determinant of S. aureus capable ofinhibiting the recruitment ofleukocytes to the site ofbacterial invasion. We have demonstrated the presence of antibodies to CHIPS throughout the population of sera examined. Using a model cell system, we have also identified a role for a high level of anti-CHIPS antibodies in either the inhibition or enhancement of bacterial pathogenesis by modulating binding of CHIPS to the C5a receptor, CD88.
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Guy, Rebecca Ann. "Giardia lamblia : an analysis of trophozoite antigens using monoclonal antibodies". Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=55696.
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Daniels, Craig. "Characterisation of proteins involved in Shigella flexneri O-antigen biosynthesis". Title page, abstract and contents only, 1999. http://web4.library.adelaide.edu.au/theses/09PH/09phd186.pdf.
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Corrigenda pasted onto back end-papers. Bibliography: leaves 163-182. Analyses the proteins involved in Shigella flexneri O-antigen biosynthesis at the molecular level in order to gain a more concise understanding of the biosynthesis machinery and how it functions.
Livros sobre o assunto "Antigens Analysis Molecular aspects"
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International Congress on Cellular and Molecular Aspects of Glucuronidation (1988 Montpellier, France). Cellular and molecular aspects of glucuronidation. London: Libbey, 1988.
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Edwards-Moulds, JoAnn. Standards for molecular testing for red cell, platelet, and neutrophil antigens. Bethesda, Md: AABB, 2008.
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Wright, Bob W. Supercritical fluid chromatography for high molecular weight organic analysis. Research Triangle Park, NC: U.S. Environmental Protection Agency, Air and Energy Engineering Research Laboratory, 1986.
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Molecular components of hepatitis B virus. Boston: Nijhoff, 1985.
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1949-, Müller S. C., ed. Synthetic peptides as antigens. Amsterdam: Elsevier, 1999.
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Beadchip molecular immunohematology: Toward routine donor and patient antigen profiling by DNA analysis. New York: Springer, 2011.
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International Congress on Cellular and Molecular Aspects of Glucuronidation. (1988 Montpellier, France). Cellular and molecular aspects of glucuronidation =: Aspects cellulaires et moleculaires de la glucuronoconjugaison : proceedings of the International Congress on Cellular and Molecular Aspects of Glucuronidation, held in Montpellier (France), 27-29 April 1988. London: Libbey, 1988.
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Koopmans, Rudy J. Engineering aspects of self-organizing materials. Amsterdam: Elsevier Academic Press, 2009.
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Shigeyuki, Hamada, ed. Molecular microbiology and immunobiology of Streptococcus Mutans ; proceedings of an International Conference on "Cellular, Molecular, and Clinical Aspects of Streptococcus Mutans" held in Birmingham, Alabama, USA, on September 18-20, 1985. Amsterdam: Elsevier Science Publishers, 1986.
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Naeim, Faramarz. Hematopathology: Morphology, immunophenotype, cytogenetics and molecular approaches. Amsterdam: Elsevier/Academic Press, 2008.
Encontre o texto completo da fonteCapítulos de livros sobre o assunto "Antigens Analysis Molecular aspects"
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Peterson, Jerry A., David Larocca, Gary Walkup, Richard Amiya e Roberto L. Ceriani. "Molecular Analysis of Epitopic Heterogeneity of the Breast Mucin". In Breast Epithelial Antigens, 55–68. Boston, MA: Springer US, 1991. http://dx.doi.org/10.1007/978-1-4615-3740-3_6.
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Geliebter, Jan, Richard A. Zeff, Rita Spathis, Gertrude Pfaffenbach, Mayumi Nakagawa, Brigid McCue, Hiroshi Mashimo et al. "The Analysis of H-2 Mutants: Molecular Genetics and Structure/Function Relationships". In H-2 Antigens, 169–76. Boston, MA: Springer US, 1987. http://dx.doi.org/10.1007/978-1-4757-0764-9_16.
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Tennstedt, Pierre, e Guido Sauter. "Quality Aspects of TMA Analysis". In Methods in Molecular Biology, 17–26. Totowa, NJ: Humana Press, 2010. http://dx.doi.org/10.1007/978-1-60761-806-5_2.
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Bruzzone, Carol M., e Clifford J. Steer. "High-Resolution Melting Analysis of Single Nucleotide Polymorphisms". In Molecular Typing of Blood Cell Antigens, 5–27. New York, NY: Springer New York, 2015. http://dx.doi.org/10.1007/978-1-4939-2690-9_2.
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Wreschner, D. H., I. Tsarfaty, M. Hareuveni, J. Zaretsky, N. I. Smorodinsky, S. Zrihan, M. Burstein et al. "Molecular Analysis of H23 Epithelial Tumor Antigen - Differentially Spliced Full Length cDNAs and Gene". In Breast Epithelial Antigens, 1–13. Boston, MA: Springer US, 1991. http://dx.doi.org/10.1007/978-1-4615-3740-3_1.
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Łukasik, Ewa, Kazimiera Waśniowska, Magdalena Grodecka, Edyta Majorczyk e Marcin Czerwiński. "High-Resolution Melting Analysis for Genotyping Duffy Blood Group Antigens". In Molecular Typing of Blood Cell Antigens, 83–95. New York, NY: Springer New York, 2015. http://dx.doi.org/10.1007/978-1-4939-2690-9_7.
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Fichou, Yann, e Claude Férec. "Molecular RHD-RHCE Analysis by Multiplex PCR of Short Fluorescent Fragments". In Molecular Typing of Blood Cell Antigens, 97–104. New York, NY: Springer New York, 2015. http://dx.doi.org/10.1007/978-1-4939-2690-9_8.
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Matis, Louis A., Simona B. Sorger, Pamela J. Fink, David L. McElligot e Stephen M. Hedrick. "Molecular Analysis of Major Histocompatibility Complex (MHC) Molecule Recognition by the T Cell Receptor Alpha-Beta (α-β) Heterodimer". In H-2 Antigens, 465–77. Boston, MA: Springer US, 1987. http://dx.doi.org/10.1007/978-1-4757-0764-9_46.
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Tabeta, Koichi, e Kazuhisa Yamazaki. "Analysis of Immune Responses to Purified Recombinant Antigens of Periodontal Pathogens". In Methods in Molecular Biology, 345–57. Totowa, NJ: Humana Press, 2010. http://dx.doi.org/10.1007/978-1-60761-820-1_21.
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Servoss, Shannon L., Rachel Gonzalez, Susan Varnum e Richard C. Zangar. "High-Throughput Analysis of Serum Antigens Using Sandwich ELISAs on Microarrays". In Methods in Molecular Biology, 143–50. Totowa, NJ: Humana Press, 2009. http://dx.doi.org/10.1007/978-1-60327-811-9_10.
Texto completo da fonteTrabalhos de conferências sobre o assunto "Antigens Analysis Molecular aspects"
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Ungur, Petru, Elisabeta Patcas, Petru A. Pop, Silviu Corbu e Florin M. Marcu. "Theoretical and Practical Aspects About Bio-Lubrication of Synovial Joints by Radioactive Molecular Treatment". In ASME 2008 9th Biennial Conference on Engineering Systems Design and Analysis. ASMEDC, 2008. http://dx.doi.org/10.1115/esda2008-59160.
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The paper has presented the result of tests and researches realized at our university and Oncology Clinical Hospital from Oradea, Radiotherapy Section, about improving of biolubrication between cartilages in relative moving of synovial joints with osteoarthritis, having slow evolution under non-conventional treatment of irradiation with gamma ray. By radioactive molecular treatment of synovial joints with gamma ray, type hinge of knee and spheres of disorder hip (gon-arthrosis and cox-arthrosis), changed molecular structures of porous cartilages and of synovial fluid in contact. All these due to partial recovering of mechanical-elastic and damper system that was spoiling, with a great reducer of pains, altering some orthopedic and non-conventional treatments at overweight patients, which are been impossible by surgery. This paper has presented a theoretical model of human body subjected the applied and conjunction forces, which explained the damping of vibrations and shocks inside of synovial joints by elastic modulus-E of bone cartilages in contact and variation of dynamic viscosity-η of synovial fluid. This work had proposed to promoted osteoarthritis therapy by using irradiation with gamma ray, being ones of the most modern active molecular treatments by using irradiation with particles in radiotherapy from neurological field.
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Basith, Shaherin, e Sangdun Choi. "An in-depth analysis of the molecular dynamics and structural aspects of IKB proteins". In the ACM Conference. New York, New York, USA: ACM Press, 2012. http://dx.doi.org/10.1145/2382936.2383004.
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Hidayati, Hidayati, Hasbullah Hasbullah e S. Hasri. "Methods for Detection of Foods, Cosmetics, and Drugs Through A Mitochondrial DNA Analysis (An Overview of the Molecular and the Qur’anic Aspects)". In Proceedings of the 19th Annual International Conference on Islamic Studies, AICIS 2019, 1-4 October 2019, Jakarta, Indonesia. EAI, 2020. http://dx.doi.org/10.4108/eai.1-10-2019.2291746.
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Liu, Zhiqian, e Simone Rochfort. "Current challenges in phospholipid analysis in bovine milk". In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/taft4078.
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Phospholipids (PLs) are important components of milk fat globule membranes. They not only play the role of emulsifier ensuring the stability and homogeneity of the oil/water emulsion system of milk, but also have multiple beneficial functions vis-Ã -vis human health. PLs of milk are a complex family of polar lipids comprising several classes including PC, PE, SM, PS, PI, PA, PG and so on and each class contains a mixture of hundreds of molecular species differing in fatty acid (FA) composition and/or regio-position.Although PL quantification at the class level can be achieved by using NP-LC-ELSD and 31P-NMR, LC-MS (mainly HILIC-MS and RP-LC-MS) has become the prevalent analytical system for PL identification and quantification at the molecular species level. Unfortunately, combining LC separation with high-resolution MS detection is still insufficient to differentiate FA regio-isomers and double bond (DB) positional isomers, both being widely present in milk PLs. Additional techniques such as ozonolysis, UV-photodissociation and photochemical tagging in combination with LC-MS are needed for a complete structural characterization of PLs.Despite the recent progress, huge challenges remain to be overcome both in PL identification and quantification. This talk will discuss these in conjunction with the following aspects of bovine milk PLs. 1) pros and cons of different LC-MS methods in PL identification and quantification; 2) major PL class and species identified so far in bovine milk and 3) utility of Paterno-Buchi photochemical reaction in revealing regio-isomer and DB-positional isomers.
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De Luca, Amalia, Christina M. Warboys, Narges Amini, Pedro Ferreira, Peter Gatehouse, David Firmin, Justin Mason, Spencer Sherwin e Paul C. Evans. "Image-Based Computational Hemodynamics and Microarray Analysis of the Porcine Aortic Arch Reveals a Correlation Between Shear Stress and Endothelial Cell Apoptosis". In ASME 2012 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/sbc2012-80948.
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Atherosclerosis is a focal disease that occurs predominantly at regions of the arterial tree that are exposed to disturbed blood flow, which generates low, oscillatory wall shear stress (WSS) at the lumen. WSS controls the spatial distribution of lesions by influencing numerous aspects of endothelial cell (EC) physiology, including inflammatory activation and viability. Of particular note, ECs in low shear, lesion-prone regions are characterized by increased apoptosis and turnover rates1 thus providing a potential explanation for the distinct spatial localization of lesion formation. Although the molecular mechanisms underlying the effects of WSS on EC physiology are poorly understood, they are known to involve transcriptional changes.
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Toti, F., A. Stierlé, M. L. Wiesel, A. Schwartz, J. M. Freyssinet e J. P. Cazenave. "PRODUCTION OF ANTIBODIES TO HUMAN VON WILLEBRAND FACTOR IN LAYING HENS. ISOLATION OF IMMUNOGLOBULINS AND APPLICATIONS TO THE DETECTION OF MOLECULAR DEFECTS OF VON WILLEBRAND FACTOR". In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644084.
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Von Willebrand disease (vWD) is an inherited disorder of primary hemostasis caused by deficiency or structural abnormalities of von Willebrand factor (vWF). VWF circulates in plasma and is also present in platelets. Plasma vWF, the carrier protein for factor VIII, is a large multimeric glycoprotein composed of identical subunits linked by disulfide bridges. Plasma and platelet vWF display distinct multimeric electrophoretic patterns. The different vWD subtypes can be classified either by the determination of vWFantigen (vWFíAg) and/or by multimer distribution. Antibodies to human vWF were raised in laying hens by intramuscular injections of purified human vWF. Immunoglobulins were isolated from egg yolks by selective polyethylene glycol and ammonium sulfate precipitations. These antibodies appeared to be monospecific, as they did not react with the plasma proteins of a patient with severe vWD. The pullets received weekly 50 μg vWF for 4 weeks and then had monthly injections. The antibodies occurred as early as the third injection, the yield being 300 to 500 mg of immunoglobulin per week (6-7 eggs). The titre could be constant over periods greater than 1 year. These immunoglobulins to vWF were tested in vWFíAg electroimmunoassays and for the multimer analysis of plasma and platelet vWF by electrophoresis and immunoblotting techniques. In no case could a difference be detected between assays performed with rabbit monospecific antiserum or with yolk immunoglobulins to human vWF. Ten to 12 multimers could be revealed for normal plasma vWF and up to 12 to 14 bands for normal platelet vWF (1.7% agarose). In the case of vWD, the electrophoresis patterns were identical with both antibodies. Thus, antibodies to vWF raised in laying hens are a suitable tool to detect and to characterize vWD. Although they do not interact with protein A, yolk antibodies are certainly advantageous to produce, as they do not contain IgM or IgA. Immunoglobulin fractions can contain up to 10 % of specific antibodies. Since they are available in larger quantities and are easy to isolate, larger homogeneous batches of antibodies can be obtained. This method may easily be applied to develop antibodies to a variety of antigens.
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Dias, Filipe, José Páscoa e Carlos Xisto. "Numerical Analysis of a Multi-Species MHD Model for Plasma Layer Control of Re-Entry Vehicles". In ASME 2018 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/imece2018-87467.
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Several critical aspects control the successful reentry of vehicles on the earth’s atmosphere: continuous communication, GPS signal reception and real-time telemetry. However, there are some common issues that can interfere with the instruments operation, the most typical being the radio blackout, in which the plasma layer frequency modifies the electromagnetic waves in a way that makes communications to and from the spacecraft impossible. So far, there have been several proposed techniques to mitigate radio blackout, one of which is the usage of electromagnetic fields. Previous studies have proven the effectiveness of the usage of an electric and/or magnetic fields to manipulate plasma layers. Experiments on plasma layer manipulation during hypersonic flight regime are extremely costly. Therefore, there has been a continuous interest in the development of cheaper solutions, that can guarantee a reliable degree of accuracy, such as the development of complex multiphysics computational models. These models are becoming increasingly realistic and accurate, as more and more physical aspects can be considered, greatly increasing the accuracy and range of models. However, those models need to be validated with recourse to experimental data. In this paper we propose a model that uses a Low Magnetic Reynolds number, and accounts for five common neutral species: N2, O2, NO, N and O, along with several of their respective reactions: dissociation of molecular nitrogen and oxygen, and exchange. The model chemistry is then validated based on experimental data gathered by several authors.
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Potapov, G. S., e Yu S. Kolosova. "REVISION OF FAUNA BUMBLEBEE (HYMENOPTERA: APIDAE) OF ARCHIPELAG NEW EARTH". In V International Scientific Conference CONCEPTUAL AND APPLIED ASPECTS OF INVERTEBRATE SCIENTIFIC RESEARCH AND BIOLOGICAL EDUCATION. Tomsk State University Press, 2020. http://dx.doi.org/10.17223/978-5-94621-931-0-2020-32.
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Fauna of invertebrates of the Novaya Zemlya Archipelago is rather poorly known, while a growing body of recent molecular research indicates that several Arctic species may represent endemic lineages with restricted ranges. These local endemics need special conservation efforts because of the increasing anthropogenic pressure and climate changes. Here, we re-examine the bumblebee fauna of the Novaya Zemlya Archipelago by using the phylogeographic analysis.
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Cheng, C. H., Y. W. Chang e C. W. Hong. "Multi-Scale Analysis of Transport Phenomenon Inside the SOFC Using MD and CFD Techniques". In ASME 2004 2nd International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2004. http://dx.doi.org/10.1115/fuelcell2004-2491.
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This paper analyzes the transport phenomenon of a solid oxide fuel cell (SOFC) from micro and macro aspects. The micro-scale model focuses on the ion hopping transportation inside the solid electrolyte and the macro-scale model aims at the flow phenomenon and thermal management inside the diffusion layers and the flow channel. In SOFCs, oxygen ions are conducted through the ceramic membrane of Yttria-Stablized Ziconia (YSZ), which is composed of ZrO2 and Y2O3. This paper uses molecular dynamics (MD) method to evaluate the ion conductivity of the solid electrolyte. Doping with different percentage of Y2O3, the ion hopping simulation shows that about 8 mole % gives the optimal performance. Also the higher the operation temperature, the better the ion conduction. Temperature field management is also a critical issue in the SOFC design. A set of three-dimensional computational fluid dynamics (CFD) model (including mass, momentum, energy and concentration equations) inside the porous diffusion layers and the flow channel of the SOFC were employed to estimate the cooling effect under different pattern of flow channel designs. All simulation results were validated with experiments reported from other literatures. The integration of the micro and macro-scale analyses proves to be versatile in the SOFC prototype design.
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Ostroverkhova, N. V. "DARK FOREST BEE APIS MELLIFERA MELLIFERA L. IN SIBERIA: CURRENT STATE AND WAYS OF POPULATION CONSERVATION". In V International Scientific Conference CONCEPTUAL AND APPLIED ASPECTS OF INVERTEBRATE SCIENTIFIC RESEARCH AND BIOLOGICAL EDUCATION. Tomsk State University Press, 2020. http://dx.doi.org/10.17223/978-5-94621-931-0-2020-56.
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Screening studies of the honey bee in Siberia made it possible to identify the dark forest bee Apis mellifera mellifera populations in the Tomsk region, Krasnoyarsk and Altai territories, and the Altai Republic. A comparative analysis of the genetic diversity of the dark forest bee populations of Siberia, the Urals and Europe, carried out according to the data of the molecular genetic study of the mitochondrial and nuclear genomes, suggests the existence of the Siberian ecotype of the Middle Russian breed. The studied bee colonies are characterized by a high adaptive potential (high degree of "acclimatization") and good economically significant indicators. To preserve the gene pool of the Middle Russian breed of Siberian populations, monitoring studies, ecological and genetic analysis of bee colonies as well as selection and breeding work in the Tomsk bee farm are carried out.
Relatórios de organizações sobre o assunto "Antigens Analysis Molecular aspects"
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Eldar, Avigdor, e Donald L. Evans. Streptococcus iniae Infections in Trout and Tilapia: Host-Pathogen Interactions, the Immune Response Toward the Pathogen and Vaccine Formulation. United States Department of Agriculture, dezembro de 2000. http://dx.doi.org/10.32747/2000.7575286.bard.
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In Israel and in the U.S., Streptococcus iniae is responsible for considerable losses in various fish species. Poor understanding of its virulence factors and limited know-how-to of vaccine formulation and administration are the main reasons for the limited efficacy of vaccines. Our strategy was that in order to Improve control measures, both aspects should be equally addressed. Our proposal included the following objectives: (i) construction of host-pathogen interaction models; (ii) characterization of virulence factors and immunodominant antigens, with assessment of their relative importance in terms of protection and (iii) genetic identification of virulence factors and genes, with evaluation of the protective effect of recombinant proteins. We have shown that two different serotypes are involved. Their capsular polysaccharides (CPS) were characterized, and proved to play an important role in immune evasion and in other consequences of the infection. This is an innovative finding in fish bacteriology and resembles what, in other fields, has become apparent in the recent years: S. iniae alters surface antigens. By so doing, the pathogen escapes immune destruction. Immunological assays (agar-gel immunodiffusion and antibody titers) confirmed that only limited cross recognition between the two types occurs and that capsular polysaccharides are immunodominant. Vaccination with purified CPS (as an acellular vaccine) results in protection. In vitro and ex-vivo models have allowed us to unravel additional insights of the host-pathogen interactions. S. iniae 173 (type II) produced DNA fragmentation of TMB-8 cells characteristic of cellular necrosis; the same isolate also prevented the development of apoptosis in NCC. This was determined by finding reduced expression of phosphotidylserine (PS) on the outer membrane leaflet of NCC. NCC treated with this isolate had very high levels of cellular necrosis compared to all other isolates. This cellular pathology was confirmed by observing reduced DNA laddering in these same treated cells. Transmission EM also showed characteristic necrotic cellular changes in treated cells. To determine if the (in vitro) PCD/apoptosis protective effects of #173 correlated with any in vivo activity, tilapia were injected IV with #173 and #164 (an Israeli type I strain). Following injection, purified NCC were tested (in vitro) for cytotoxicity against HL-60 target cells. Four significant observations were made : (i) fish injected with #173 had 100-400% increased cytotoxicity compared to #164 (ii) in vivo activation occurred within 5 minutes of injection; (iii) activation occurred only within the peripheral blood compartment; and (iv) the isolate that protected NCC from apoptosis in vitro caused in vivo activation of cytotoxicity. The levels of in vivo cytotoxicity responses are associated with certain pathogens (pathogen associated molecular patterns/PAMP) and with the tissue of origin of NCC. NCC from different tissue (i.e. PBL, anterior kidney, spleen) exist in different states of differentiation. Random amplified polymorphic DNA (RAPD) analysis revealed the "adaptation" of the bacterium to the vaccinated environment, suggesting a "Darwinian-like" evolution of any bacterium. Due to the selective pressure which has occurred in the vaccinated environment, type II strains, able to evade the protective response elicited by the vaccine, have evolved from type I strains. The increased virulence through the appropriation of a novel antigenic composition conforms with pathogenic mechanisms described for other streptococci. Vaccine efficacy was improved: water-in-oil formulations were found effective in inducing protection that lasted for a period of (at least) 6 months. Protection was evaluated by functional tests - the protective effect, and immunological parameters - elicitation of T- and B-cells proliferation. Vaccinated fish were found to be resistant to the disease for (at least) six months; protection was accompanied by activation of the cellular and the humoral branches.
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Wackett, Lawrence, Raphi Mandelbaum e Michael Sadowsky. Bacterial Mineralization of Atrazine as a Model for Herbicide Biodegradation: Molecular and Applied Aspects. United States Department of Agriculture, janeiro de 1999. http://dx.doi.org/10.32747/1999.7695835.bard.
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Atrazine is a broadly used herbicide in agriculture and it was used here as a model to study the biodegradation of herbicides. The bacterium Pseudomonas sp. ADP metabolizes atrazine to carbon dioxide and ammonia and chloride. The genes encoding atrazine catabolism to cyanuric acid were cloned and expressed in Escherichia coli. The genes were designated atzA, atzB and atzC. Each gene was sequenced. The enzyme activities were characterized. AtzA is atrazine chlorohydrolase which takes atrazine to hydroxyatrizine. AtzB is hydroxyatrazine N-ethylaminohydrolase which produces N-isopropylammelide and N-ethylamine. AtzC is N-isopropylammelide N-isopropylaminohydrolase which produces cyanuric acid and N-isopropylamine. Each product was isolated and characterized to confirm their identity by chromatography and mass spectrometry. Sequence analysis indicated that each of the hydrolytic enzymes AtzA, AtzB and AtzC share identity which the aminohydrolase protein superfamily. Atrazine chlorohydrolase was purified to homogeneity. It was shown to have a kcat of 11 s-1 and a KM of 150 uM. It was shown to require a metal ion, either Fe(II), Mn(II) or Co(II), for activity. The atzA, atzB and atzC genes were shown to reside on a broad-host range plasmid in Pseudomonas sp. ADP. Six other recently isolated atrazine-degrading bacteria obtained from Europe and the United States contained homologs to the atz genes identified in Pseudomonas sp. ADP. The identity of the sequences were very high, being greater than 98% in all pairwise comparisons. This indicates that many atrazine-degrading bacteria worldwide metabolize atrazine via a pathway that proceeds through hydroxyatrazine, a metabolite which is non-phytotoxic and non-toxic to mammals. Enzymes were immobilized and used for degradation of atrazine in aqueous phases. The in-depth understanding of the genomics and biochemistry of the atrazine mineralization pathway enabled us to study factors affecting the prevalence of atrazine degradation in various agricultural soils under conservative and new agricultural practices. Moreover, Pseudomonas sp. ADP and/or its enzymes were added to atrazine-contaminated soils, aquifers and industrial wastewater to increase the rate and extent of atrazine biodegradation above that of untreated environments. Our studies enhance the ability to control the fate of regularly introduced pesticides in agriculture, or to reduce the environmental impact of unintentional releases.
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Levisohn, Sharon, Maricarmen Garcia, David Yogev e Stanley Kleven. Targeted Molecular Typing of Pathogenic Avian Mycoplasmas. United States Department of Agriculture, janeiro de 2006. http://dx.doi.org/10.32747/2006.7695853.bard.
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Intraspecies identification (DNA "fingerprinting") of pathogenic avian mycoplasmas is a powerful tool for epidemiological studies and monitoring strain identity. However the only widely method available for Mycoplasma gallisepticum (MG) and M. synoviae (MS)wasrandom amplified polymorphic DNA (RAPD). This project aimed to develop alternative and supplementary typing methods that will overcome the major constraints of RAPD, such as the need for isolation of the organism in pure culture and the lack of reproducibility intrinsic in the method. Our strategy focussed on recognition of molecular markers enabling identification of MG and MS vaccine strains and, by extension, pathogenic potential of field isolates. Our first aim was to develop PCR-based systems which will allow amplification of specific targeted genes directly from clinical material. For this purpose we evaluated the degree of intraspecies heterogeneity in genes encoding variable surface antigens uniquely found in MG all of which are putative pathogenicity factors. Phylogenic analysis of targeted sequences of selected genes (pvpA, gapA, mgc2, and lp) was employed to determine the relationship among MG strains.. This method, designated gene targeted sequencing (GTS), was successfully employed to identify strains and to establish epidemiologically-linked strain clusters. Diagnostic PCR tests were designed and validated for each of the target genes, allowing amplification of specific nucleotide sequences from clinical samples. An mgc2-PCR-RFLP test was designed for rapid differential diagnosis of MG vaccine strains in Israel. Addressing other project goals, we used transposon mutagenesis and in vivo and in vitro models for pathogenicity to correlated specific changes in target genes with biological properties that may impact the course of infection. An innovative method for specific detection and typing of MS strains was based on the hemagglutinin-encoding gene vlhA, uniquely found in this species. In parallel, we evaluated the application of amplified fragment length polymorphism (AFLP) in avian mycoplasmas. AFLP is a highly discriminatory method that scans the entire genome using infrequent restriction site PCR. As a first step the method was found to be highly correlated with other DNA typing methods for MG species and strain differentiation. The method is highly reproducible and relatively rapid, although it is necessary to isolate the strain to be tested. Both AFLP and GTS are readily to amenable to computer-assisted analysis of similarity and construction of a data-base resource. The availability of improved and diverse tools will help realize the full potential of molecular typing of avian mycoplasmas as an integral and essential part of mycoplasma control programs.
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McClure, Michael A., Yitzhak Spiegel, David M. Bird, R. Salomon e R. H. C. Curtis. Functional Analysis of Root-Knot Nematode Surface Coat Proteins to Develop Rational Targets for Plantibodies. United States Department of Agriculture, outubro de 2001. http://dx.doi.org/10.32747/2001.7575284.bard.
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The goal of this research was to provide a better understanding of the interface between root-knot nematodes, Meloidogyne spp., and their host in order to develop rational targets for plantibodies and other novel methods of nematode control directed against the nematode surface coat (SC). Specific objectives were: 1. To produce additional monoclonal SC antibodies for use in Objectives 2, 3, and 4 and as candidates for development of plantibodies. 2. To determine the production and distribution of SC proteins during the infection process. 3. To use biochemical and immunological methods to perturbate the root-knot nematode SC in order to identify SC components that will serve as targets for rationally designed plantibodies. 4. To develop SC-mutant nematodes as additional tools for defining the role of the SC during infection. The external cuticular layer of nematodes is the epicuticle. In many nematodes, it is covered by a fuzzy material termed "surface coat" (SC). Since the SC is the outermost layer, it may playa role in the interaction between the nematode and its surroundings during all life stages in soil and during pathogenesis. The SC is composed mainly of proteins, carbohydrates (which can be part of glycoproteins), and lipids. SC proteins and glycoproteins have been labeled and extracted from preparasitic second-stage juveniles and adult females of Meloidogyne and specific antibodies have been raised against surface antigens. Antibodies can be used to gain more information about surface function and to isolate genes encoding for surface antigens. Characterization of surface antigens and their roles in different life-stages may be an important step towards the development of alternative control. Nevertheless, the role of the plant- parasitic nematode's surface in plant-nematode interaction is still not understood. Carbohydrates or carbohydrate-recognition domains (CROs) on the nematode surface may interact with CROs or carbohydrate molecules, on root surfaces or exudates, or be active after the nematode has penetrated into the root. Surface antigens undoubtedly play an important role in interactions with microorganisms that adhere to the nematodes. Polyclonal (PC) and monoclonal (MC) antibodies raised against Meloidogyne javanica, M. incognita and other plant-parasitic nematodes, were used to characterize the surface coat and secreted-excreted products of M. javanica and M. incognita. Some of the MC and PC antibodies raised against M. incognita showed cross-reactivity with the surface coat of M. javanica. Further characterization, in planta, of the epitopes recognized by the antibodies, showed that they were present in the parasitic juvenile stages and that the surface coat is shed during root penetration by the nematode and its migration between root cells. At the molecular level, we have followed two lines of experimentation. The first has been to identify genes encoding surface coat (SC) molecules, and we have isolated and characterized a small family of mucin genes from M. incognita. Our second approach has been to study host genes that respond to the nematode, and in particular, to the SC. Our previous work has identified a large suite of genes expressed in Lycopersicon esculentum giant cells, including the partial cDNA clone DB#131, which encodes a serine/threonine protein kinase. Isolation and predicted translation of the mature cDNA revealed a frame shift mutation in the translated region of nematode sensitive plants. By using primers homologous to conserved region of DB#131 we have identified the orthologues from three (nematode-resistant) Lycopersicon peruvianum strains and found that these plants lacked the mutation.
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Vakharia, Vikram, Shoshana Arad, Yonathan Zohar, Yacob Weinstein, Shamila Yusuff e Arun Ammayappan. Development of Fish Edible Vaccines on the Yeast and Redmicroalgae Platforms. United States Department of Agriculture, fevereiro de 2013. http://dx.doi.org/10.32747/2013.7699839.bard.
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Betanodaviruses are causative agents of viral nervous necrosis (VNN), a devastating disease of cultured marine fish worldwide. Betanodavirus (BTN) genome is composed of two single-stranded, positive-sense RNA molecules. The larger genomic segment, RNA1 (3.1 kb), encodes the RNA-dependent RNA polymerase, while the smaller genomic segment, RNA 2 (1.4kb), encodes the coat protein. This structural protein is the host-protective antigen of VNN which assembles to form virus-like particles (VLPs). BTNs are classified into four genotypes, designated red-spotted grouper nervous necrosis virus (RGNNV), barfin flounder nervous necrosis virus (BFNNV), tiger puffer nervous necrosis virus (TPNNV), and striped jack nervous necrosis virus (SJNNV), based on phylogenetic analysis of the coat protein sequences. RGNNV type is quite important as it has a broad host-range, infecting warm-water fish species. At present, there is no commercial vaccine available to prevent VNN in fish. The general goal of this research was to develop oral fish vaccines in yeast and red microalgae (Porphyridium sp.) against the RGNNV genotype. To achieve this, we planned to clone and sequence the coat protein gene of RGNNV, express the coat protein gene of RGNNV in yeast and red microalgae and evaluate the immune response in fish fed with recombinantVLPs antigens produced in yeast and algae. The collaboration between the Israeli group and the US group, having wide experience in red microalgae biochemistry, molecular genetics and large-scale cultivation, and the development of viral vaccines and eukaryotic protein expression systems, respectively, was synergistic to produce a vaccine for fish that would be cost-effective and efficacious against the betanodavirus infection.
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Zhang, Hongbin, Shahal Abbo, Weidong Chen, Amir Sherman, Dani Shtienberg e Frederick Muehlbauer. Integrative Physical and Genetic Mapping of the Chickpea Genome for Fine Mapping and Analysis of Agronomic Traits. United States Department of Agriculture, março de 2010. http://dx.doi.org/10.32747/2010.7592122.bard.
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Chickpea is the third most important pulse crop in the world and ranks first in the Middle East; however, it has been subjected to only limited research in modern genomics. In the first period of this project (US-3034-98R) we constructed two large-insert BAC and BIBAC libraries, developed 325 SSR markers and mapped QTLs controlling ascochyta blight resistance (ABR) and days to first flower (DTF). Nevertheless, the utilities of these tools and results in gene discovery and marker-assisted breeding are limited due to the absence of an essential platform. The goals of this period of the project were to use the resources and tools developed in the first period of the project to develop a BAC/BIBAC physical map for chickpea and using it to identify BAC/BIBACcontigs containing agronomic genes of interest, with an emphasis on ABR and DTF, and develop DNA markers suitable for marker-assisted breeding. Toward these goals, we proposed: 1) Fingerprint ~50,000 (10x) BACs from the BAC and BIBAC libraries, assemble the clones into a genome-wide BAC/BIBAC physical map, and integrate the BAC/BIBAC map with the existing chickpea genetic maps (Zhang, USA); 2) fine-map ABR and DTFQTLs and enhance molecular tools for chickpea genetics and breeding (Shahal, Sherman and DaniShtienberg, Israel; Chen and Muehlbauer; USA); and 3) integrate the BAC/BIBAC map with the existing chickpea genetic maps (Sherman, Israel; Zhang and Chen, USA). For these objectives, a total of $460,000 was requested originally, but a total of $300,000 was awarded to the project. We first developed two new BAC and BIBAC libraries, Chickpea-CME and Chickpea- CHV. The chickpea-CMEBAC library contains 22,272 clones, with an average insert size of 130 kb and equivalent to 4.0 fold of the chickpea genome. The chickpea-CHVBIBAC library contains 38,400 clones, with an average insert size of 140 kb and equivalent to 7.5 fold of the chickpea genome. The two new libraries (11.5 x), along with the two BAC (Chickpea-CHI) and BIBAC (Chickpea-CBV) libraries (7.1 x) constructed in the first period of the project, provide libraries essential for chickpea genome physical mapping and many other genomics researches. Using these four libraries we then developed the proposed BAC/BIBAC physical map of chickpea. A total of 67,584 clones were fingerprinted, and 64,211 (~11.6 x) of the fingerprints validated and used in the physical map assembly. The physical map consists of 1,945 BAC/BIBACcontigs, with each containing an average of 39.2 clones and having an average physical length of 559 kb. The contigs collectively span ~1,088 Mb, being 1.49 fold of the 740- Mb chickpea genome. Third, we integrated the physical map with the two existing chickpea genetic maps using a total of 172 (124 + 48) SSR markers. Fourth, we identified tightly linked markers for ABR-QTL1, increased marker density at ABR-QTL2 and studied the genetic basis of resistance to pod abortion, a major problem in the east Mediterranean, caused by heat stress. Finally, we, using the integrated map, isolated the BAC/BIBACcontigs containing or closely linked to QTL4.1, QTL4.2 and QTL8 for ABR and QTL8 for DTF. The integrated BAC/BIBAC map resulted from the project will provide a powerful platform and tools essential for many aspects of advanced genomics and genetics research of this crop and related species. These includes, but are not limited to, targeted development of SNP, InDel and SSR markers, high-resolution mapping of the chickpea genome and its agronomic genes and QTLs, sequencing and decoding of all genes of the genome using the next-generation sequencing technology, and comparative genome analysis of chickpea versus other legumes. The DNA markers and BAC/BIBACcontigs containing or closely linked to ABR and DTF provide essential tools to develop SSR and SNP markers well-suited for marker-assisted breeding of the traits and clone their corresponding genes. The development of the tools and knowledge will thus promote enhanced and substantial genetic improvement of the crop and related legumes.
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Sessa, Guido, e Gregory Martin. MAP kinase cascades activated by SlMAPKKKε and their involvement in tomato resistance to bacterial pathogens. United States Department of Agriculture, janeiro de 2012. http://dx.doi.org/10.32747/2012.7699834.bard.
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The research problem: Pseudomonas syringae pv. tomato (Pst) and Xanthomonas campestrispv. vesicatoria (Xcv) are the causal agents of tomato bacterial speck and spot diseases, respectively. These pathogens colonize the aerial parts of the plant and cause economically important losses to tomato yield worldwide. Control of speck and spot diseases by cultural practices or chemicals is not effective and genetic sources of resistance are very limited. In previous research supported by BARD, by gene expression profiling we identified signaling components involved in resistance to Xcvstrains. Follow up experiments revealed that a tomato gene encoding a MAP kinase kinase kinase (MAPKKKe) is required for resistance to Xcvand Pststrains. Goals: Central goal of this research was to investigate the molecular mechanisms by which MAPKKKεand associated MAP kinase cascades regulate host resistance. Specific objectives were to: 1. Determine whether MAPKKKεplays a broad role in defense signaling in plants; 2. Identify components of MAP kinase cascades acting downstream of MAPKKKε; 3. Determine the role of phosphorylation-related events in the function of MAPKKKε; 4. Isolate proteins directly activated by MAPKKKε-associatedMAPK modules. Our main achievements during this research program are in the following major areas: 1. Characterization of MAPKKKεas a positive regulator of cell death and dissection of downstream MAP kinase cascades (Melech-Bonfil et al., 2010; Melech-Bonfil and Sessa, 2011). The MAPKKKεgene was found to be required for tomato resistance to Xcvand Pstbacterial strains and for hypersensitive response cell death triggered by different R gene/effector gene pairs. In addition, overexpression analysis demonstrated that MAPKKKεis a positive regulator of cell death, whose activity depends on an intact kinase catalytic domain. Epistatic experiments delineated a signaling cascade downstream of MAPKKKεand identified SIPKK as a negative regulator of MAPKKKε-mediated cell death. Finally, genes encoding MAP kinase components downstream of MAPKKKεwere shown to contribute to tomato resistance to Xcv. 2. Identification of tomato proteins that interact with MAPKKKεand play a role in plant immunity (Oh et al., 2011). We identified proteins that interact with MAPKKKε. Among them, the 14-3-3 protein TFT7 was required for cell death mediated by several R proteins. In addition, TFT7 interacted with the MAPKK SlMKK2 and formed homodimersin vivo. Thus, TFT7 is proposed to recruit SlMKK2 and MAPKKK client proteins for efficient signal transfer. 3. Development of a chemical genetic approach to identify substrates of MAPKKKε-activated MAP kinase cascades (Salomon et al., 2009, 2011). This approach is based on engineering the kinase of interest to accept unnatural ATP analogs. For its implementation to identify substrates of MAPKKKε-activated MAP kinase modules, we sensitized the tomato MAP kinase SlMPK3 to ATP analogs and verified its ability to use them as phosphodonors. By using the sensitized SlMPK3 and radiolabeled N6(benzyl)ATP it should be possible to tag direct substrates of this kinase. 4. Development of methods to study immunity triggered by pathogen-associated molecular patterns (PAMPs) in tomato and N. benthamiana plants (Kim et al., 2009; Nguyen et al. 2010). We developed protocols for measuring various PTI-associatedphenotypes, including bacterial populations after pretreatment of leaves with PAMPs, induction of reporter genes, callose deposition at the cell wall, activation of MAP kinases, and a luciferase-based reporter system for use in protoplasts. Scientific and agricultural significance: Our research activities discovered and characterized a signal transduction pathway mediating plant immunity to bacterial pathogens. Increased understanding of molecular mechanisms of immunity will allow them to be manipulated by both molecular breeding and genetic engineering to produce plants with enhanced natural defense against disease. In addition, we successfully developed new biochemical and molecular methods that can be implemented in the study of plant immunity and other aspects of plant biology.
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Cohen, Jerry D., e Ephraim Epstein. Metabolism of Auxins during Fruit Development and Ripening. United States Department of Agriculture, agosto de 1995. http://dx.doi.org/10.32747/1995.7573064.bard.
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We had proposed to look at several aspects of auxin metabolism in fruit tissues: 1) IAA biosynthesis from tryptophan and IAA biosynthesis via the non-tryptophan pathway; 2) changes in the capacity to form conjugates and catabolites of auxin at different times during fruit development and; 3) the effects of modifying auxin metabolism in fruit tissues. The latter work focused primarily on the maize iaglu gene, with initial studies also using a bacterial gene for hydrolysis of IAA-aspartate. These metabolic and molecular studies were necessary to define potential benefits of auxin metabolism modification and will direct future efforts for crop improvement by genetic methods. An in vitro system was developed for the production of tomato fruit in culture starting from immature flowers in order to ascertain the effect of auxin modification on fruit ripening. IAA supplied to the fruit culture media prior to breaker stage resulted in an increase in the time period between breaker and red-ripe stages from 7 days without additional IAA to 12 days when 10-5 M IAA was added. These results suggest that significant changes in the ripening period could be obtained by alteration of auxin relationships in tomato fruit. We generated transgenic tomato plants that express either the maize iaglu gene or reduced levels of the gene that encodes the enzyme IAA-glucose synthetase. A modified shuttle vector pBI 121 expressing the maize iaglu gene in both sense and antisense orientations under a 35S promoter was used for the study. The sense plants showed total lack of root initiation and development. The antisense transgenic plants, on the other hand, had unusually well developed root systems at early stages in development. Analysis showed that the amount and activity of the endogenous 75 kDa IAGLU protein was reduced in these plants and consequently these plants had reduced levels of IAA-glucose and lower overall esterified IAA.
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Tel-Zur, Neomi, e Jeffrey J. Doyle. Role of Polyploidy in Vine Cacti Speciation and Crop Domestication. United States Department of Agriculture, janeiro de 2012. http://dx.doi.org/10.32747/2012.7697110.bard.
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1. Abstract: Over the past 25 years, vine cacti of the genera Hylocereus and Selenicereus have been introduced into Israel and southern California as new exotic fruit crops. The importance of these crops lies in their high water use efficiency and horticultural potential as exotic fruit crops. Our collaboration focused on the cytological, molecular and evolutionary aspects of vine cacti polyploidization to confront the agricultural challenge of genetic improvement, ultimately to improve success of vine cacti as commercial fruit crop plants. More specifically, we worked on the: 1- Identification of the putative ancestor(s) of the tetraploid H. megalanthus; 2- Determination of the number of origins of H. megalanthus (single vs. multiple origins of polyploidy); 3- Cytogenetic analysis of BC1 and F1 hybrids; 4- Determination of important agricultural traits and the selection of superior hybrids for cultivation. The plant material used in this study comprised interspecific Hylocereus F1 and first backcross (BC1) hybrids, nine Hylocereus species (58 genotypes), nine Selenicereus species (14 genotypes), and four Epiphyllum genotypes. Two BC1 hexaploids (BC-023 and BC-031) were obtained, a high ploidy level that can be explained only by a fertilization event between one unreduced female gamete from the triploid hybrid and a balanced gamete from the pollen donor, the diploid H. monacanthus. These findings are scientific evidence that support the possibility that “hybridization followed by chromosome doubling” could also occur in nature. Cytomixis, the migration of chromatin between adjacent cells through connecting cytoplasmatic channels, was observed in vine cacti hybrids and may thus imply selective DNA elimination in response to the allopolyploidization process. Evidence from plastid and nrDNA internal transcribed spacers (ITS) sequences support the placement of H. megalanthus within a monophyletic Hylocereus group. Furthermore, both plastid and ITS datasets are most consistent with a conclusion that this tetraploid species is an autopolyploid, despite observations that the species appears to be morphologically intermediate between Hylocereus and Selenicereus. Although the possibility of very narrow allopolyploidly (i.e., derivation from parents that are barely diverged from each other such as closely related species in the same genus) cannot be ruled out entirely based on our data (in part due to the unavailability of Hylocereus species considered to be morphologically the closest relatives of H. megalanthus), the possibility of H. megalanthus representing an intergeneric cross (i.e., Hylocereus × Selenicereus) seems extremely unlikely. Interestingly, the process of homogenization of ITS sequences (concerted evolution) is either incomplete or lacking in both Hylocereus and Selenicereus, and the inclusion of several artificial hybrids in the molecular study revealed the potential for biparental plastid inheritance in Hylocereus. The most important agricultural implication of this research project was the information collected for F1 and BC1 hybrids. Specifically, this project concluded with the selection of four superior hybrids in terms of fruit quality and potential yields under extreme high temperatures. These selected hybrids are self-compatible, avoiding the need for hand cross pollination to set fruits, thus reducing manpower costs. We recently offered these hybrids to growers in Israel for prioritized rapid evaluation and characterization.
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Dolja, Valerian V., Amit Gal-On e Victor Gaba. Suppression of Potyvirus Infection by a Closterovirus Protein. United States Department of Agriculture, março de 2002. http://dx.doi.org/10.32747/2002.7580682.bard.
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The plant virus family Polyviridae is the largest and most destructive of all plant viruses. Despite the continuous effort to develop resistant plant varieties, there is a desperate need for novel approaches conferring wide-range potyvirus resistance. Based on experiments with the tobacco etch potyvirus (TEV)-derived gene expression vector, we suggested approach for screening of the candidate resistance genes. This approach relies on insertion of the genes into a virus vector and evaluation of the phenotypes of the resulting recombinant viruses. The genes which suppress infection by the recombinant virus are selected as candidates for engineering transgenic resistance. Our analysis of the TEV variants expressing proteins of the beet yellows closterovirus (BYV) revealed that one of those, the leader proteinase (L-Pro), strongly and specifically interfered with the hybrid TEV infection. Since closterovirus L-Pro is evolutionary related to potyviral helper component-proteinase (HC-Pro), we suggested that the L-Pro interfered with HC-Pro function via a trans-dominant inhibitory effect. Based on these findings, we proposed to test two major hypotheses. First, we suggested that L-Pro-mediated suppression of potyvirus infection is a general phenomenon effective against a range of potyviruses. The second hypothesis stated that the suppression effect can be reproduced in transgenic plants expressing L-Pro, and can be utilized for generation of resistance to potyviruses. In accord with these hypotheses, we developed two original objectives of our proposal: A) to determine the range of the closterovirus-derived suppression of potyviral infection, and B) to try and utilize the L-Pro-mediated suppression for the development of transgenic resistance to potyviruses. In the first phase of the project, we have developed all major tools and technologies required for successful completion of the proposed research. These included TEV and ZYMV vectors engineered to express several closteroviral L-Pro variants, and generation of the large collection of transgenic plants. To our satisfaction, characterization of the infection phenotypes exhibited by chimeric TEV and ZYMV variants confirmed our first hypothesis. For instance, similar to TEV-L- Pro(BYV) chimera, ZYMV-L-Pro(LIYV) chimera was debilitated in its systemic spread. In contrast, ZYMV-GUS chimera (positive control) was competent in establishing vigorous systemic infection. These and other results with chimeric viruses indicated that several closteroviral proteinases inhibit long-distance movement of the potyviruses upon co-expression in infected plants. In order to complete the second objective, we have generated ~90 tobacco lines transformed with closteroviral L-Pro variants, as well as ~100 lines transformed with BYV Hsp70-homolog (Hsp70h; a negative control). The presence and expression of the trans gene in each line was initially confirmed using RT-PCR and RNA preparations isolated from plants. However, since detection of the trans gene-specific RNA can not guarantee production of the corresponding protein, we have also generated L-Pro- and Hsp70h-specific antisera using corresponding synthetic peptides. These antisera allowed us to confirm that the transgenic plant lines produced detectable, although highly variable levels of the closterovirus antigens. In a final phase of the project, we tested susceptibility of the transgenic lines to TEV infection. To this end, we determined that the minimal dilution of the TEV inoculum that is still capable of infecting 100% of nontransgenic plants was 1:20, and used 10 plants per line (in total, ~2,000 plants). Unfortunately, none of the lines exhibited statistically significant reduction in susceptibility. Although discouraging, this outcome prompted us to expand our experimental plan and conduct additional experiments. Our aim was to test if closteroviral proteinases are capable of functioning in trans. We have developed agroinfection protocol for BYV, and tested if co- expression of the L-Pro is capable of rescuing corresponding null-mutant. The clear-cut, negative results of these experiments demonstrated that L-Pro acts only in cis, thus explaining the lack of resistance in our transgenic plants. We have also characterized a collection of the L-Pro alanine- scanning mutants and found direct genetic evidence of the requirement for L-Pro in virus systemic spread. To conclude, our research supported by BARD confirmed one but not another of our original hypotheses. Moreover, it provided an important insight into functional specialization of the viral proteinases and generated set of tools and data with which we will be able to address the molecular mechanisms by which these proteins provide a variety of critical functions during virus life cycle.