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Artykuły w czasopismach na temat "Stress proteins"
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Srivastava, K. K., i Ganju Lilly. "Stress proteins". Indian Journal of Clinical Biochemistry 7, nr 1 (styczeń 1992): 11–14. http://dx.doi.org/10.1007/bf02867695.
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Donaldson, Laurie. "Don't stress, proteins". Materials Today 14, nr 7-8 (lipiec 2011): 305. http://dx.doi.org/10.1016/s1369-7021(11)70154-7.
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Gehrmann, M., D. Schilling, M. Molls i G. Multhoff. "Radiation induced stress proteins". Int. Journal of Clinical Pharmacology and Therapeutics 48, nr 07 (1.07.2010): 492–93. http://dx.doi.org/10.5414/cpp48492.
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KOBAYASHI, Kazuko. "Rolls of Stress Proteins." Zen Nihon Shinkyu Gakkai zasshi (Journal of the Japan Society of Acupuncture and Moxibustion) 47, nr 2 (1997): 37–41. http://dx.doi.org/10.3777/jjsam.47.37.
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Mollenhauer, Juergen. "STRESS PROTEINS IN MEDICINE". Shock 5, nr 5 (maj 1996): 390. http://dx.doi.org/10.1097/00024382-199605000-00016.
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Graven, Krista K., i Harrison W. Farber. "Endothelial hypoxic stress proteins". Kidney International 51, nr 2 (luty 1997): 426–37. http://dx.doi.org/10.1038/ki.1997.57.
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Winrow, V. "Stress proteins in medicine". Annals of the Rheumatic Diseases 55, nr 5 (1.05.1996): 287. http://dx.doi.org/10.1136/ard.55.5.287.
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POLLA, BARBARA S., MARIA BACHELET, GIULIANO ELIA i M. GABRIELLA SANTORO. "Stress Proteins in Inflammationa". Annals of the New York Academy of Sciences 851, nr 1 STRESS OF LIF (czerwiec 1998): 75–85. http://dx.doi.org/10.1111/j.1749-6632.1998.tb08979.x.
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Roma, Paola, i Alberico Luigi Catapano. "Stress proteins and atherosclerosis". Atherosclerosis 127, nr 2 (grudzień 1996): 147–54. http://dx.doi.org/10.1016/s0021-9150(96)05952-7.
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Blumenthal, Elliott J. "Stress proteins in medicine". Trends in Endocrinology & Metabolism 7, nr 5 (lipiec 1996): 193. http://dx.doi.org/10.1016/1043-2760(96)00059-8.
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Ibrahim, Yasser Musa. "Stress response proteins in Streptococcus pneumoniae". Thesis, University of Glasgow, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.412962.
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Bradley, Dominic. "The universal stress proteins of bacteria". Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/6946.
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Universal stress proteins (USPs) are a widespread and abundant protein family often linked to survival during stress. However, their exact biochemical and cellular roles are incompletely understood. Mycobacterium tuberculosis (Mtb) has 10 USPs, of which Rv1636 appears to be unique in its domain structure and being the only USP conserved in M. leprae. Over-expression of Rv1636 in M. smegmatis indicated that this protein does not share the growth arrest phenotype of another Mtb USP, Rv2623, suggesting distinct roles for the Mtb USPs. Purified Rv1636 was shown to have novel nucleotide binding capabilities when subjected to UV crosslinking. A range of site-directed mutants of Rv1636 were produced, including mutations within a predicted nucleotide binding motif, with the aim of identifying and characterising key residues within the Rv1636 protein. Further putative biochemical activities, including nucleotide triphosphatase, nucyleotidylyation and auto-phosphorylation were also investigated in vitro; however Rv1636 could not be shown to definitively possess these activities, raising the possibility that addition factors may be present in vivo. Bioinformatic analysis of Rv1636 has provided an in-depth look at the protein. The crystal structure of Rv1636 shows a strand swapped dimer conformation that appears to block the predicted nucleotide binding site, providing a possible reason for the low NTPase activity previously observed. Truncated Rv1636 constructs were successfully generated, in which the strand swapped dimer was disrupted, and subjected to biophysical analysis, including analytical ultracentrifugation and size exclusion chromatography combined with multi-angle light scattering. Previous Mtb single-USP mutants are known to have no phenotype under a range of stress conditions. For this reason the P. aeruginosa USP PA3309, which does possess a stress survival phenotype, was also investigated. This provided the opportunity to investigate the role of USPs and their putative nucleotide binding motif in vivo. Site-directed mutants of PA3309 were generated to investigate the role of the nucleotide binding motif in vivo. It remains to be determined if the survival defect observed for ΔPA3309 strain can be complemented with these mutants as the vector system used in these experiments proved unable to integrate into the attB site of the genome. Through the analysis of the USPs from mycobacteria and Pseudomonas, the aim was to elucidate a greater understanding of the role of Rv1636 in Mtb and the role of USPs in general. The bioinformatic and biochemical analyses of USPs, in addition to the site directed mutants generated as a result of this work, will provide a strong foundation for future studies.
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Gregory, Mary Sarah-Jane, i n/a. "Thioredoxin and Oxidative Stress". Griffith University. School of Health Science, 2004. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20040301.082639.
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The experiments described in this thesis involve the expression and characterisation of recombinant truncated thioredoxin (tTrx) and the potential involvement that thioredoxin (Trx) has in the cellular responses to oxidative stress. Truncated Trx (80 amino acids) was expressed from a plasmid containing the ORF for tTrx that had been introduced into E.coli BL-21(DE3) cells. The protein was initially extracted using a combination of high concentrations of urea, high pH levels, and multiple sonification steps to remove the tTrx from inclusion bodies formed during expression. This procedure produced a stable solution of tTrx. Purification of tTrx from this protein solution required anion exchange chromatography followed by gel permeation in a HPLC system to obtain fully purified, recombinant tTrx which allowed further characterisation studies to be undertaken. An initial investigation into tTrx was performed to determine some basic physical, biochemical and functional aspects of this hitherto relatively undefined protein. Analysis by sedimentation equilibrium indicated that freshly prepared tTrx forms a single species with a molecular weight of 18.8kDa. This value indicates that recombinant tTrx naturally forms a dimer in solution that was shown to be non-covalent in nature and stable in solution. The capacity of tTrx to reduce protein disulphide bonds was determined using the insulin reduction assay. Results show that tTrx lacks this particular redox ability. The rate of oxidisation at 4 degrees C was analysed using free thiol determination, sedimentation equilibrium and SDS-PAGE patterning. Results indicated a steady rise in the degree of oxidation of tTrx over an eight day period. After six days the oxidated protein consistently displayed the presence of intramolecular disulphide bonds. Covalently-linked disulphide dimers and higher molecular weight oligomers were detectable after eight days oxidation. An investigation of the reducing capacity of the basic Trx system determined that fully oxidised tTrx was unable to act alone as a substrate for thioredoxin reductase (TR). However, when reduced Trx was added to the system, it appeared capable of acting as an electron donor to the oxidised tTrx in order to reduce disulphide groups. Recombinant tTrx was successfully radiolabelled with Trans 35S-methionine/cysteine for use in cell association studies. No evidence was found to indicate the presence of a receptor for tTrx on either MCF-7 or U-937 cells. Findings suggest that a low level of non-specific binding of tTrx to these cell lines rather than a classical ligand-binding mechanism occurs thus suggesting the absence of a cell surface receptor for tTrx. The role that Trx may play in the cellular responses to oxidative stress was also investigated. The chemical oxidants hydrogen peroxide (H2O2) and diamide were used to establish an in vitro model of oxidative stress for the choriocarcinoma cytotrophoblast cell line JEG-3. Cellular function was assessed in terms of membrane integrity, metabolic activity and the ability to synthesis new DNA following exposure to these oxidants. Results indicated that both agents were capable of causing cells to undergo oxidative stress without inducing immediate apoptosis or necrosis. Initially, JEG-3 cells exposed to 38μM or 75μM H2O2 or 100μM diamide were shown to display altered cell metabolism and DNA synthesis without loss to cell viability or membrane integrity. Cells were also shown to be capable of some short-term recovery but later lapsed into a more stressed state. Expression levels of Trx were studied to determine whether this type of chemical stress caused a change in intercellular protein levels. Both cELISA and western blotting results indicated that only cells exposed to 100μM diamide displayed any significant increase in Trx protein levels after 6 or 8hrs exposure to the oxidant. Further studies over a longer time-frame were also performed. These found that when JEG-3 cells were exposed to 18μM H2O2 or 200μM diamide over 12-48hrs, a positive correlation between increasing endogenous Trx protein levels and a decline in cell proliferation was observed. Cytotrophoblast cells, which are responsible for implantation and placentation, are susceptible to oxidative stress in vivo and their anti-oxidant capacity is fundamental to the establishment of pregnancy. The findings obtained during these studies suggest that Trx plays a role in this process.
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Gregory, Mary Sarah-Jane. "Thioredoxin and Oxidative Stress". Thesis, Griffith University, 2004. http://hdl.handle.net/10072/367183.
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The experiments described in this thesis involve the expression and characterisation of recombinant truncated thioredoxin (tTrx) and the potential involvement that thioredoxin (Trx) has in the cellular responses to oxidative stress.
Truncated Trx (80 amino acids) was expressed from a plasmid containing the ORF for tTrx that had been introduced into E.coli BL-21(DE3) cells. The protein was initially extracted using a combination of high concentrations of urea, high pH levels, and multiple sonification steps to remove the tTrx from inclusion bodies formed during expression. This procedure produced a stable solution of tTrx. Purification of tTrx from this protein solution required anion exchange chromatography followed by gel permeation in a HPLC system to obtain fully purified, recombinant tTrx which allowed further characterisation studies to be undertaken.
An initial investigation into tTrx was performed to determine some basic physical, biochemical and functional aspects of this hitherto relatively undefined protein. Analysis by sedimentation equilibrium indicated that freshly prepared tTrx forms a single species with a molecular weight of 18.8kDa. This value indicates that recombinant tTrx naturally forms a dimer in solution that was shown to be non-covalent in nature and stable in solution. The capacity of tTrx to reduce protein disulphide bonds was determined using the insulin reduction assay. Results show that tTrx lacks this particular redox ability.
The rate of oxidisation at 4 degrees C was analysed using free thiol determination, sedimentation equilibrium and SDS-PAGE patterning. Results indicated a steady rise in the degree of oxidation of tTrx over an eight day period. After six days the oxidated protein consistently displayed the presence of intramolecular disulphide bonds. Covalently-linked disulphide dimers and higher molecular weight oligomers were detectable after eight days oxidation.
An investigation of the reducing capacity of the basic Trx system determined that fully oxidised tTrx was unable to act alone as a substrate for thioredoxin reductase (TR). However, when reduced Trx was added to the system, it appeared capable of acting as an electron donor to the oxidised tTrx in order to reduce disulphide groups.
Recombinant tTrx was successfully radiolabelled with Trans 35S-methionine/cysteine for use in cell association studies. No evidence was found to indicate the presence of a receptor for tTrx on either MCF-7 or U-937 cells. Findings suggest that a low level of non-specific binding of tTrx to these cell lines rather than a classical ligand-binding mechanism occurs thus suggesting the absence of a cell surface receptor for tTrx.
The role that Trx may play in the cellular responses to oxidative stress was also investigated. The chemical oxidants hydrogen peroxide (H2O2) and diamide were used to establish an in vitro model of oxidative stress for the choriocarcinoma cytotrophoblast cell line JEG-3. Cellular function was assessed in terms of membrane integrity, metabolic activity and the ability to synthesis new DNA following exposure to these oxidants. Results indicated that both agents were capable of causing cells to undergo oxidative stress without inducing immediate apoptosis or necrosis. Initially, JEG-3 cells exposed to 38μM or 75μM H2O2 or 100μM diamide were shown to display altered cell metabolism and DNA synthesis without loss to cell viability or membrane integrity. Cells were also shown to be capable of some short-term recovery but later lapsed into a more stressed state.
Expression levels of Trx were studied to determine whether this type of chemical stress caused a change in intercellular protein levels. Both cELISA and western blotting results indicated that only cells exposed to 100μM diamide displayed any significant increase in Trx protein levels after 6 or 8hrs exposure to the oxidant. Further studies over a longer time-frame were also performed. These found that when JEG-3 cells were exposed to 18μM H2O2 or 200μM diamide over 12-48hrs, a positive correlation between increasing endogenous Trx protein levels and a decline in cell proliferation was observed. Cytotrophoblast cells, which are responsible for implantation and placentation, are susceptible to oxidative stress in vivo and their anti-oxidant capacity is fundamental to the establishment of pregnancy. The findings obtained during these studies suggest that Trx plays a role in this process.Thesis (Masters)
Master of Philosophy (MPhil)
School of Health Sciences
Full Text
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Fladvad, Malin. "Structure and function in c-Myc and Grx4 : two key proteins involved in transcriptional activation and oxidative stress /". Stockholm, 2006. http://diss.kib.ki.se/2006/91-7357-007-9/.
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Naim, Adnan. "The Role of G3BPs in the Stress Response Pathway". Thesis, Griffith University, 2016. http://hdl.handle.net/10072/367499.
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The ras-GTPase SH3-domain Binding Proteins (G3BP) are a family of RNA-binding proteins that have been implicated in multiple cellular activities ranging from signal transduction to regulation of messenger RNA (mRNA). G3BPs were named after their interaction with the SH3 domain of Ras-GTPase-activating protein; however recent research did not find this interaction. All three members of the G3BPs family, G3BP1, G3BP2a and G3BP2b, share structural similarities with each other by having four distinct regions (1) the Nuclear Transporting Factor 2, (NTF2) domain at the N-terminal, (2) the acidic and proline-rich domain in the centre, (3) the RNA recognition motif (RRM) and (4) the arginine glycine (RGG)-rich region rich at the C-terminal. The presence of the NTF2 domain in its structure suggests G3BP might play a role in nucleocytoplasmic transportation, which was observed after serum stimulation where G3BP1 was translocated to the nucleus from the cytoplasm. The RNA recognition motif (RRM) region plays a vital role in its interaction with the target RNA. The RGG-rich box is a region rich in arginine and glycine residues, which plays a role assisting RRM in interactions with protein or RNA.
G3BP1 is found to be overexpressed in many cancers, including breast cancer, and head and neck tumours, as well as cell lines derived from human lung, prostrate, colon, thyroid and breast cancer. G3BPs have also been implicated in translational control within differentiating neurons, suggesting that G3BP may play several roles in controlling the translational fate of its cargo and that its role may be cell-specific. G3BP1 has also been found in β-integrin- induced adhesion complexes. This information highlights G3BPs as a dynamic protein that is involved in several biological functions.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Natural Sciences
Science, Environment, Engineering and Technology
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Doherty, Sean. "Apoplastic proteins, enzymes and radicals". Thesis, Durham University, 2000. http://etheses.dur.ac.uk/4376/.
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The soluble and readily extractable part of the plant extracellular matrix has been termed, the apoplast and contains a wide range of components such as, complex carbohydrates, structural proteins, enzymes and radicals that are known to be responsive to stress and developmental pressures. This thesis describes the development of a technique for the selective enrichment of apoplastic components for a range of subsequent analyses. Using this technique a number of apoplastic proteins were N-terminally sequenced and revealed 2 cell wall related enzymes, an antifungal protein and 3 auxin-binding/germin-like proteins. This technique also provided a novel approach to the further study of auxin-binding proteins via the use of affinity chromatography at their putative site of action, the apoplast. Three potential auxin-binding protiens were identified. Many attempts were made to subject the material extracted from the apoplast to the highly resolving technique of 2-dimensional electrophoresis, and during the process two unusual 2D systems were developed. These systems could be run in a small format that permitted very rapid analysis and/or using an in-gel loading strategy to subject up to 500µg of protein to 2D separation therefore permitting N-terminal sequencing from single 2D gels. Unfortunately 2D separation of apoplastic proteins was never fully achieved within the time frame of this study due to the vast degree of heterogenity present in the sample material. It did however demonstrate the very complex nature of apoplastic components. A series of experiments revealed that the tobacco leaf apoplast contained compartment specific antioxidant enzymes, some of which share physical characteristics with similar enzymes from other species. The activity of these enzymes altered in response to stress and according to the developmental age of the tissue. The reduced activity of these enzymes directly correlated to the degree of oxidative modification of apoplastic proteins illustrating that these enzymes are important in the detoxification of apoplastic radicals. Follow on experiments following the apoplastic generation of the superoxide anion and nitric oxide from impact stressed potato tuber tissue showed that radicals play important roles in the responses of plant tissue to stress, and show the first involvement of nitric oxide in plants in response to abiotic stress.
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Amara, Imen. "Abiotic stress in plants: Late Embryogenesis Abundant proteins". Doctoral thesis, Universitat de Barcelona, 2012. http://hdl.handle.net/10803/83820.
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In order to improve our understanding on LEA proteins and their molecular functions in drought tolerance, the present work analyzes in the first place, the composition of LEA subproteomes from Arabidopsis seeds and maize embryos; second, three maize embryo LEA proteins from groups 1, 2, and 3 are analyzed in order to detect functional differences among them and finally, transgenic maize plants over-expressing group 5 “rab28” lea gene are characterized. The following results are presented:
- Chapter 1. Proteomic approach to analyze the composition of LEA subproteomes from
Arabidopsis seeds by mass spectrometry. The main objective was the development and isolation method to obtain enriched LEA populations from Arabidopsis seeds. LEA subproteomes were obtained using an extraction procedure that combines heat stability and acid solubility of LEA proteins. To identify the protein content, we followed two approaches: first, a classical 1D (SDSPAGE) gel-based procedure associated with MS analysis using an electrospray ionization source coupled on-line to liquid chromatography (LC-ESI-MSMS) and second, a gel-free protocol associated with an off-line HPLC and analysis via matrix assisted laser desorption/ionization (LC-MALDI-MSMS).
- Chapter 2. Proteomic analysis of LEA proteins accumulated in maize mature seeds. Identification of LEA protein content by mass spectrometry and selection of three LEA proteins, Emb564, Rab17 and Mlg3, as representatives of groups 1, 2 and 3 for further study. Comparative functional analysis covering different aspects of maize Emb564, Rab17 and Mlg3 proteins, posttranslational modifications, subcellular localization and their properties in in-vitro and in- vivo assays.
- Chapter 3. Characterization of transgenic maize plants expressing maize group 5 rab28 LEA gene under the ubiquitin promoter. Evaluation of Rab28 transcripts and protein levels, phenotype and stress tolerance traits of transgenic plants under drought stress. Investigation of the subcellular localization of transgenic and wild-type Rab28 protein using immunocytochemical approaches.Las proteínas LEA, originalmente fueron descritas en las semillas de algodón; se acumulan en grandes cantidades en estructuras tolerantes a la desecación (semillas, polen) y en tejidos vegetativos sometidos a estrés abiótico, sequía, salinidad y frío. También se hallan en organismos anidrobióticos, en plantas de resurrección, algunos invertebrados y microorganismos. La presencia de proteínas LEA se correlaciona con la adquisición de tolerancia a la desecación. Desde un principio se les atribuyó un papel en las respuestas de las plantas en la adaptación al estrés (revisado en Bartels and Salamini 2001, Tunnacliffe 2007, Shih et al. 2010, Tunnacliffe 2010, Hand et al. 2011). Las proteínas LEA se clasifican en diversos grupos en función de dominios y secuencias de aminoácidos específicos (Wise 2010, Batagglia et al 2008, Bies-Ethève et al 2008). Los grupos 1, 2 y 3 son los más relevantes ya que abarcan la mayoría de las proteínas de la familia LEA. Una característica general de estas proteínas es su elevada hidrofilicidad, alto contenido de aminoácidos cargados y su falta de estructura en estado hidratado. A pesar de encontrarse mayoritariamente en forma de “random coil”, algunas adquieren un cierto grado de estructura durante la deshidratación o en la presencia de agentes promotores de α-hélices (Shih et al. 2010, Hand et al. 2011). A nivel celular se han hallado en todas las localizaciones, citosol, núcleo, nucleolo, mitocondria, cloroplasto, vacuola, retículo endoplásmico, peroxisoma y membrana plasmática, donde se supone ejercen su función protectora frente al estrés (Tunnacliffe and Wise 2007, Hundertmark and Hincha 2008). En relación a las modificaciones post-traduccionales, algunas se hallan fosforiladas (Jiang and Wang 2004; Plana et al. 1991, Heyen et al. 2002, Rohrig et al. 2006). Los efectos protectores de las varias proteínas LEA se han demostrado mediante ensayos in vitro y en aproximaciones transgénicas que han dado lugar a fenotipos resistentes a la sequía, sal y frío. Por lo general, se considera que estas proteínas contribuyen a la protección y a la estabilización de macromoléculas y estructuras celulares en las respuestas de adaptación al estrés en plantas; sin embargo, sus funciones específicas aún no han sido esclarecidas. A nivel molecular se ha propuesto que las funciones de las proteínas LEA pueden ser variadas: estabilización y renaturalización de proteínas, mantenimiento de membranas, en combinación, o no, con azúcares, tampones de hidratación (substitución de moléculas de agua), afinidad por iones y función antioxidante (Tunnacliffe and Wise 2007, Shih et al. 2010, Batagglia et al. 2008). Para finalizar, diremos que los objetivos principales de esta tesis consisten en ampliar los conocimientos sobre las proteínas LEA y sus funciones relativas a la tolerancia a la sequía. Los resultados están presentados en forma de capítulos.
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Kolodziejski, Jakub. "Twist proteins as oxidative and hypoxic stress regulators". Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTS008/document.
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Les facteurs de transcription Twist1 et Twist2 (famille Twist) jouent un rôle majeur dans le développement embryonnaire et dans la progression tumorale. Leur potentiel oncogénique dérive directement de la combinaison de leurs nombreuses activités développementales. Les gènes Twist peuvent notamment, en induisant la transition épithélio-mésenchymateuse (EMT), promouvoir l’invasion des cellules cancéreuses et participer de ce fait aux processus métastatique. De plus, en bloquant l’activité des voies de signalisation Rb et p53, ils peuvent inhiber les deux principaux programmes de sauvegarde cellulaire que sont l’apoptose et la senescence. Enfin, ils sont également impliqués dans la résistance des cellules cancéreuses aux agents chimio-thérapeutiques. En plus de ces nombreuses activités, nos données préliminaires nous ont amené à considérer un rôle de Twist dans la réponse au stress. Les cellules cancéreuses doivent croitre dans un environnement en perpétuel changement qui génère de nombreux types de stress. Seules les cellules capables de s’adapter, peuvent survivre et acquérir de nouvelles capacités les rendant plus agressives. La résistance au stress fait donc partie intégrante de la progression tumorale. Nos travaux révèlent que Twist en induisant une résistance au stress, plus particulièrement métabolique, est un acteur essentiel de l’acquisition d’u phénotype agressif des cellules cancéreuses. Dans une première étude, nous avons montré que Twist module le stress oxydatif, une condition très fréquemment retrouvée dans les tumeurs. Ainsi, nos résultats indiquent que l’expression de Twist provoque une réduction du taux d’espèces réactives de l’oxygène (ROS) intracellulaire. Cette activité a pour conséquence directe d’induire une résistance accrue à l’apoptose déclenchée par divers traitements. Nous avons par la suite caractérisé cette activité et mis en évidence un programme génétique contrôlé par Twist impliquant divers facteurs possédant des propriétés anti-oxydantes. Dans un second temps, nous nous sommes intéressés à un autre type de stress métabolique, l’hypoxie. L’hypoxie définie par un taux insuffisant d’oxygène, est retrouvée dans la plupart des tumeurs solides du fait de l’absence ou de l’anomalité de la vascularisation. L’hypoxie mène à la stabilisation d’un facteur de transcription, HIF1α. Cette protéine est essentielle à l’adaptation hypoxique et contrôle l’expression de nombreux gènes impliqués dans le métabolisme du glucose, le transport de l’oxygène, l’angiogenèse ou l’apoptose. Dans les premiers temps d’hypoxie, l’effet d’adaptation induit par HIF1α est bénéfique pour les cellules. Cependant, si l’absence d’oxygène se prolonge, HIF1α, peut pousser les cellules vers la mort. Nos travaux démontrent que Twist est capable de rendre les cellules résistantes à une hypoxie prolongée. De plus, cette activité de protection contre le stress hypoxique agit via un effet paracrine. Enfin, nos données suggèrent que cet effet est médié par une interaction directe entre les protéines Twist et HIF1α. Au final, cette étude indique que l’expression de Twist dans les cellules cancéreuses, en conférant une résistance accrue à l’environnement hypoxique, joue un rôle essentiel dans l’adaptation au stress et à l’acquisition de nouveaux phénotypes agressifs. En résumé, L’objectif principal de ma thèse était de mettre en évidence de nouvelles propriétés cellulaires des oncogènes de la famille Twist. Nos résultats démontrent que Twist par ses capacités à contrôler le stress métabolique, permet à la cellule cancéreuse de mieux s’adapter et donc survivre dans un environnement en constante évolution. Nos travaux renforcent donc la notion de l’importance de ces facteurs dans la progression tumoraleTwist1 and Twist2 are related transcription factors that play major roles both during embryonic development and in several pathologies, including cancer. Twists' oncogenic potential arises from a combination of their multiple functions in development. Notably, both Twist induce epithelial-to mesenchymal transition, thus promoting tumour invasiveness and possibly conferring to cells self-renewal properties. Furthermore, through disruption of both Rb- and p53-driven pathways, Twist override two major oncogene-induced fail-safe programs, namely senescence and apoptosis, thereby promoting malignant conversion. Twist has also been reported to participate in acquisition of drug resistance and in promotion of neo-angiogenesis.Current knowledge of pleiotropic activities of Twist prompted us to postulate that these factors may be major regulators of stress response. Cancer cells survive and grow within a continuously changing environment that creates multiple stresses to which they must adapt in order to survive and strive. Such adaptations often give rise to the acquisition of an aggressive phenotype. Consistent with this hypothesis, we recently unveiled new activities of Twist proteins that are related to stress response. We have shown that Twist regulates response to oxidative stress, a condition exacerbated in cancer by stimuli such as inflammation, increased cellular metabolism and changes in tumour oxygenation. Our work has contributed to the understanding of molecular mechanisms through which Twist diminishes cellular ROS and thus participates in the escape from apoptosis and senescence. In the first part of my thesis, I worked on the antioxidant activity of Twist and described its molecular mechanisms.The second part of my work addressed the impact of Twist proteins on cellular response to hypoxia that is insufficient oxygen supply, frequently found in solid tumours. Cellular response to hypoxic stress relies on stabilization and activation of HIF1α, a key transcriptional mediator of the hypoxic response, regulating numerous genes involved in glucose metabolism, oxygen transport, angiogenesis, cell growth and apoptosis. HIF1α is beneficial for cancer cells in response to short hypoxic episodes, however its sustained activation in case of prolonged hypoxia may push cancer cells towards apoptosis. In this context, we have shown that Twist protects cancer cells from hypoxia-induced apoptosis. We have discovered HIF1α and Twist physically interact, suggesting a possible mechanistic basis for Twist's protective effect. These results led us to postulate that Twist plays a role in cellular response to hypoxia and thus participates in cancer cell adaptation and acquisition of aggressive phenotypes triggered by lack of oxygen.Our results reinforce the notion that Twist factors are major cellular stress modulators that might be important for adaptation of cancer cells to changing conditions in the process of tumour progression
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Di, Paolo Tiziano. "Stress response in Entamoeba histolytica". Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=68169.
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The heat shock response was studied in the intestinal parasitic protozoan Entamoeba histolytica. Temperature shifts from 37$ sp circ$C to 44$ sp circ$C enhanced the synthesis of five major heat shock (or stress) proteins (HSP) of 100, 50, 42, 37, and 28 kDa. Similarly, exposure of amebae to lymphokine activated macrophages and hydrogen peroxide caused HSP expression. Heat shock caused the reversible inhibition of amebic adherence to Chinese hamster ovary cells and human colonic mucin binding to trophozoites by ${>80 %}$. This was due to a decrease in the surface expression of the Gal/GalNAc adherence lectin and a marked reduction in the lectin mRNA expression. However, the presence of target Chinese hamster ovary cells during recovery at 37$ sp circ$C augmented amebic adherence. These results suggest that E. histolytica trophozoites produce a variety of HSP in response to different stimuli and can modulate the expression of the surface adherence lectin which maybe important in pathogenesis.
Książki na temat "Stress proteins"
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Schlesinger, Milton J., M. Gabriella Santoro i Enrico Garaci, red. Stress Proteins. Berlin, Heidelberg: Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-75815-7.
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Latchman, David S., red. Stress Proteins. Berlin, Heidelberg: Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/978-3-642-58259-2.
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Arrigo, André-Patrick, i W. E. G. Müller, red. Small Stress Proteins. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-642-56348-5.
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Calderwood, Stuart K., red. Cell Stress Proteins. New York, NY: Springer New York, 2007. http://dx.doi.org/10.1007/978-0-387-39717-7.
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K, Calderwood Stuart, red. Cell stress proteins. New York: Springer, 2007.
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1953-, Eden Willem van, i Young Douglas B, red. Stress proteins in medicine. New York: M. Dekker, 1996.
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Asea, Alexzander A. A., i Punit Kaur, red. Heat Shock Proteins and Stress. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-90725-3.
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J, Schlesinger Milton, Santoro M. G i Garaci E, red. Stress proteins: Induction and function. Berlin: Springer-Verlag, 1990.
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Marius, Locke, i Noble Earl George, red. Exercise and stress response: The role of stress proteins. Boca Raton, Fla: CRC Press, 2002.
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Simon, Stéphanie. Small stress proteins and human diseases. Hauppauge, N.Y: Nova Science, 2010.
Znajdź pełny tekst źródłaCzęści książek na temat "Stress proteins"
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Pfanner, Nikolaus. "Mitochondrial Protein Import: Unfolding and Refolding of Precursor Proteins". W Stress Proteins, 71–79. Berlin, Heidelberg: Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-75815-7_6.
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Latchman, D. S. "Stress Proteins: An Overview". W Stress Proteins, 1–7. Berlin, Heidelberg: Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/978-3-642-58259-2_1.
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Shi, Y., i R. I. Morimoto. "Autoregulation of the Heat Shock Response". W Stress Proteins, 225–41. Berlin, Heidelberg: Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/978-3-642-58259-2_10.
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Brown, I. R., i F. R. Sharp. "The Cellular Stress Gene Response in Brain". W Stress Proteins, 243–63. Berlin, Heidelberg: Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/978-3-642-58259-2_11.
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Carroll, R., i D. M. Yellon. "Heat Stress Proteins and Their Relationship to Myocardial Protection". W Stress Proteins, 265–79. Berlin, Heidelberg: Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/978-3-642-58259-2_12.
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Bachelet, M., G. Multhoff, M. Vignola, K. Himeno i B. S. Polla. "Heat Shock Proteins in Inflammation and Immunity". W Stress Proteins, 281–303. Berlin, Heidelberg: Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/978-3-642-58259-2_13.
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Morange, M. "Heat Shock Proteins in Embryonic Development". W Stress Proteins, 305–27. Berlin, Heidelberg: Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/978-3-642-58259-2_14.
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van Eden, W. "Heat Shock Proteins in Rheumatoid Arthritis". W Stress Proteins, 329–46. Berlin, Heidelberg: Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/978-3-642-58259-2_15.
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Newton, S. G., i D. M. Altmann. "Heat Shock Protein 60 and Type I Diabetes". W Stress Proteins, 347–61. Berlin, Heidelberg: Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/978-3-642-58259-2_16.
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Ristori, G., C. Montesperelli, D. Kovacs, G. Borsellino, L. Battistini, C. Buttinelli, C. Pozzilli, C. Mattei i M. Salvetti. "Heat Shock Proteins and Multiple Sclerosis". W Stress Proteins, 363–80. Berlin, Heidelberg: Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/978-3-642-58259-2_17.
Pełny tekst źródłaStreszczenia konferencji na temat "Stress proteins"
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Kaazempur-Mofrad, Mohammad R., Peter J. Mack, Helene Karcher, Javad Golji i Roger G. Kamm. "Stress-Induced Mechanotransduction: Some Preliminaries". W ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-43215.
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Mechanical stimuli affect nearly every aspect of cellular function, yet the underlying mechanisms of transduction of force into biochemical signals are not clearly understood. One hypothesis is that forces transmitted via individual proteins, either at the site of cell adhesion to its surroundings or within the stress-bearing members of the cytoskeleton, cause conformational changes that change their binding affinity to other intracellular molecules. This altered equilibrium state can subsequently initiate biochemical signaling cascades of produce immediate structural changes. This paper addresses the distribution of forces within the cell resulting from specific mechanical stimuli, computed using a 3-D multi compartment, continuum, viscoelastic finite element model, and uses these to estimate the forces transmitted by individual proteins and protein complexes. These levels of force are compared to those known to produce conformational changes in cytoskeletal proteins, as speculated from magnetocytometry observations and computed by molecular dynamics.
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Sampson, Alana C., Eunna Chung i Marissa Nichole Rylander. "Thermal Stress Conditioning to Induce Osteogenic Protein Expression for Bone Regeneration". W ASME 2012 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/sbc2012-80940.
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Although bone has the intrinsic ability to “self-heal”, there are circumstances in which its regenerative capacity is limited or compromised, such as in critical bone defects. In these cases, the lack of osteogenic proteins at the wound site can prevent healing and external stimuli may be necessary to encourage bone growth [1]. Exogenous delivery of proteins and growth factors directly to the wound has been successful in bone regeneration, but is limited by the instability of the proteins and short half-lives. As a result, administration of multiple large doses of protein is necessary to retain a beneficial protein level. Due to these disadvantages, additional methods have been investigated to supply essential proteins to the bone defect [2].
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Koroleva, E. S., P. V. Kuzmitskaya i O. Yu Urbanovich. "IMPACT OF DROUGHT STRESS ON STRESS-ASSOCIATED PROTEINS APPLE GENES EXPRESSION LEVEL". W SAKHAROV READINGS 2021: ENVIRONMENTAL PROBLEMS OF THE XXI CENTURY. International Sakharov Environmental Institute, 2021. http://dx.doi.org/10.46646/sakh-2021-1-268-271.
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Stress-associated proteins (SAP) in many plants are involved in the response to adverse factors of biotic and abiotic nature. In order to study changes in the expression level of SAP genes in apple trees, MM-106 rootstocks were exposed to drought for 24 h. Expression profiles of 14 studied genes encoding SAP were established during the quantitative PCR reaction (qPCR), among which wererevealed of actively expressed under specified conditions. The majority of SAP genes have maximum transcript accumulation by 4 hours of exposure to drought.
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Koroleva, E. S., P. V. Kuzmitskaya i O. Yu Urbanovich. "IMPACT OF DROUGHT STRESS ON STRESS-ASSOCIATED PROTEINS APPLE GENES EXPRESSION LEVEL". W SAKHAROV READINGS 2021: ENVIRONMENTAL PROBLEMS OF THE XXI CENTURY. International Sakharov Environmental Institute, 2021. http://dx.doi.org/10.46646/sakh-2021-1-268-271.
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Stress-associated proteins (SAP) in many plants are involved in the response to adverse factors of biotic and abiotic nature. In order to study changes in the expression level of SAP genes in apple trees, MM-106 rootstocks were exposed to drought for 24 h. Expression profiles of 14 studied genes encoding SAP were established during the quantitative PCR reaction (qPCR), among which wererevealed of actively expressed under specified conditions. The majority of SAP genes have maximum transcript accumulation by 4 hours of exposure to drought.
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Chung, Eunna, i Marissa Nichole Rylander. "Effects of Growth Factors and Stress Conditioning on the Induction of Heat Shock Proteins and Osteogenesis". W ASME 2009 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2009. http://dx.doi.org/10.1115/sbc2009-206662.
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Tissue engineering is an emerging field that focuses on development of methods for repairing and regenerating damaged or diseased tissue. Successful development of engineered tissues is often limited by insufficient cellular proliferation and insufficient formation of extracellular matrix. To induce effective bone regeneration, many research groups have investigated the cellular response and capability for tissue regeneration associated with bioreactor conditions and addition of growth factors [1]. Bioreactors in tissue engineering have been developed to expose cells to a similar stress environment as found within the body or induce elevated stress levels for potential induction of specific cellular responses associated with tissue regeneration. Native bone encounters a diverse array of dynamic stresses such as shear, tensile, and compression daily. Stress conditioning protocols in the form of thermal or tensile stress have been shown to induce up-regulation of molecular chaperones called heat shock proteins (HSPs) and bone-related proteins like MMP13 (matrix metallopeptidase 13) [2] and OPG (osteoprotegerin) [3, 4]. HSPs have important roles in enhancing cell proliferation and collagen synthesis. Osteogenic growth factors such as TGF-β1 (transforming growth factor beta 1) and BMP-2 (bone morphogenetic protein 2) are related to bone remodeling and osteogenesis as well as HSP induction [5]. Therefore, identification of effective preconditioning using growth factors and stress protocols that enhance HSP expression could substantially advance development of bone regeneration. The purpose of this research was to identify preconditioning protocols using osteogenic growth factors and tensile stress applied through a bioreactor system to enhance expression of HSPs and bone-related proteins while minimizing cellular injury for ultimate use for bone regeneration.
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Li, Dai-xi, i Xiaoming He. "Desiccation Dependent Structure and Stability of an Anhydrobiotic Nematode Late Embryogenesis Abundant (LEA) Protein". W ASME 2009 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2009. http://dx.doi.org/10.1115/sbc2009-206862.
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A number of organisms have been found to be capable of surviving severe water deficit as a result of extreme drought and cold in nature by entering a state of suspended animation (i.e., anhydrobiosis or life without water) [1]. Although the precise molecular repertoire of desiccation tolerance in anhydrobiotic organisms is still not fully understood, results from recent studies indicate the crucial role of stress proteins such as the late embryogenesis abundant (LEA) proteins [2]. LEA proteins have been proposed to play a variety of roles in protecting biologicals from damaging by dehydration stress such as molecular chaperone and shield, ion chelator, antioxidant, and space filler. The multifunctional capacity of LEA proteins has been attributed in part to their structural plasticity: they are unfolded and when fully hydrated and become folded during water deficit [1]. However, the structural stability of LEA protein in response to desiccation is still not fully understood. In this study, the structure alteration of a group 3 LEA protein from an anhydrobiotic nematode (AavLEA1) [2] were investigated using the molecular dynamics (MD) simulation approach to understand the structural stability at different water contents.
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Ramirez, Angelica Maria, Begoña Calvo Calzada i Jorge Grasa. "The Effect of the Fascia on the Stress Distribution in Skeletal Muscle". W ASME 2010 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2010. http://dx.doi.org/10.1115/sbc2010-19696.
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The human and vertebrate interaction with the environment is done primarily through the movement. This is possible due the skeletal muscle: anatomical structure able to contract voluntarily. The skeletal muscles are made up of contractile proteins which slide one over another allowing the muscle shortening and the body force generation. This protein structure of actin and myosin maintains its organization through the connective tissue that surrounds it (endomysium, perimysium and epimysium), creating arrays of myofibrils, fibre bundles, fascicles until conform the whole muscle. All this connective tissue extends to the ends of the muscle to form the tendon.
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Morinobu, M., M. Ishijima, S. R. Rittling, K. Tsuji, H. Yamamoto, A. Nifuji, D. T. Denhardt i M. Noda. "OSTEOPONTIN-DEFICIENCY REDUCES BONE FORMATION UNDER MECHANICAL STRESS". W 3rd International Conference on Osteopontin and SIBLING (Small Integrin-Binding Ligand, N-linked Glycoprotein) Proteins, 2002. TheScientificWorld Ltd, 2002. http://dx.doi.org/10.1100/tsw.2002.319.
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Chung, Eunna, i Marissa Nichole Rylander. "Multi-Stress Conditioning Can Synergisticly Enhance Production of Osteogenic Markers and Heat Shock Proteins". W ASME 2010 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2010. http://dx.doi.org/10.1115/sbc2010-19511.
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Tissue regeneration can be enhanced by introduction of biochemical and mechanical cues. We investigated the effect of thermal and mechanical stress alone or in combination with growth factors (GFs) (BMP-2 and TGF-β1) on cell proliferation and induction of heat shock proteins and bone-related proteins by MC3T3-E1mouse preosteoblasts. Thermal and mechanical stress conditioning alone induced bone-related proteins such as osteocalcin (OCN), vascular endothelial growth factor (VEGF), osteoprotegerin (OPG), and osteopontin (OPN) and heat shock proteins (HSP27, HSP47, HSP70). Cell proliferation was increased by cyclic tension in combination with growth factors. Combined thermal and mechanical stress induced synergistic expression of HSPs and VEGF. Therefore, utilization of thermal and tensile stress conditioning can stimulate bone healing or regeneration.
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Sanchez-Lopez, Elsa, Laura Menchén, Esther Seco, Teresa Gómez del Pulgar, Juan Carlos Lacal i Arancha Cebrián. "Abstract 2644: Inhibition of choline kinase increases endoplasmic reticulum stress proteins". W Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL. American Association for Cancer Research, 2011. http://dx.doi.org/10.1158/1538-7445.am2011-2644.
Pełny tekst źródłaRaporty organizacyjne na temat "Stress proteins"
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Christopher, David A., i Avihai Danon. Plant Adaptation to Light Stress: Genetic Regulatory Mechanisms. United States Department of Agriculture, maj 2004. http://dx.doi.org/10.32747/2004.7586534.bard.
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Original Objectives: 1. Purify and biochemically characterize RB60 orthologs in higher plant chloroplasts; 2. Clone the gene(s) encoding plant RB60 orthologs and determine their structure and expression; 3. Manipulate the expression of RB60; 4. Assay the effects of altered RB60 expression on thylakoid biogenesis and photosynthetic function in plants exposed to different light conditions. In addition, we also examined the gene structure and expression of RB60 orthologs in the non-vascular plant, Physcomitrella patens and cloned the poly(A)-binding protein orthologue (43 kDa RB47-like protein). This protein is believed to a partner that interacts with RB60 to bind to the psbA5' UTR. Thus, to obtain a comprehensive view of RB60 function requires analysis of its biochemical partners such as RB43. Background & Achievements: High levels of sunlight reduce photosynthesis in plants by damaging the photo system II reaction center (PSII) subunits, such as D1 (encoded by the chloroplast tpsbAgene). When the rate of D1 synthesis is less than the rate of photo damage, photo inhibition occurs and plant growth is decreased. Plants use light-activated translation and enhanced psbAmRNA stability to maintain D1 synthesis and replace the photo damaged 01. Despite the importance to photosynthetic capacity, these mechanisms are poorly understood in plants. One intriguing model derived from the algal chloroplast system, Chlamydomonas, implicates the role of three proteins (RB60, RB47, RB38) that bind to the psbAmRNA 5' untranslated leader (5' UTR) in the light to activate translation or enhance mRNA stability. RB60 is the key enzyme, protein D1sulfide isomerase (Pill), that regulates the psbA-RN :Binding proteins (RB's) by way of light-mediated redox potentials generated by the photosystems. However, proteins with these functions have not been described from higher plants. We provided compelling evidence for the existence of RB60, RB47 and RB38 orthologs in the vascular plant, Arabidopsis. Using gel mobility shift, Rnase protection and UV-crosslinking assays, we have shown that a dithiol redox mechanism which resembles a Pill (RB60) activity regulates the interaction of 43- and 30-kDa proteins with a thermolabile stem-loop in the 5' UTR of the psbAmRNA from Arabidopsis. We discovered, in Arabidopsis, the PD1 gene family consists of II members that differ in polypeptide length from 361 to 566 amino acids, presence of signal peptides, KDEL motifs, and the number and positions of thioredoxin domains. PD1's catalyze the reversible formation an disomerization of disulfide bonds necessary for the proper folding, assembly, activity, and secretion of numerous enzymes and structural proteins. PD1's have also evolved novel cellular redox functions, as single enzymes and as subunits of protein complexes in organelles. We provide evidence that at least one Pill is localized to the chloroplast. We have used PDI-specific polyclonal and monoclonal antisera to characterize the PD1 (55 kDa) in the chloroplast that is unevenly distributed between the stroma and pellet (containing membranes, DNA, polysomes, starch), being three-fold more abundant in the pellet phase. PD1-55 levels increase with light intensity and it assembles into a high molecular weight complex of ~230 kDa as determined on native blue gels. In vitro translation of all 11 different Pill's followed by microsomal membrane processing reactions were used to differentiate among PD1's localized in the endoplasmic reticulum or other organelles. These results will provide.1e insights into redox regulatory mechanisms involved in adaptation of the photosynthetic apparatus to light stress. Elucidating the genetic mechanisms and factors regulating chloroplast photosynthetic genes is important for developing strategies to improve photosynthetic efficiency, crop productivity and adaptation to high light environments.
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Vierling, E. Role of HSP100 proteins in plant stress tolerance. Final technical report. Office of Scientific and Technical Information (OSTI), sierpień 1998. http://dx.doi.org/10.2172/638185.
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Sadot, Einat, Christopher Staiger i Mohamad Abu-Abied. Studies of Novel Cytoskeletal Regulatory Proteins that are Involved in Abiotic Stress Signaling. United States Department of Agriculture, wrzesień 2011. http://dx.doi.org/10.32747/2011.7592652.bard.
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In the original proposal we planned to focus on two proteins related to the actin cytoskeleton: TCH2, a touch-induced calmodulin-like protein which was found by us to interact with the IQ domain of myosin VIII, ATM1; and ERD10, a dehydrin which was found to associate with actin filaments. As reported previously, no other dehydrins were found to interact with actin filaments. In addition so far we were unsuccessful in confirming the interaction of TCH2 with myosin VIII using other methods. In addition, no other myosin light chain candidates were found in a yeast two hybrid survey. Nevertheless we have made a significant progress in our studies of the role of myosins in plant cells. Plant myosins have been implicated in various cellular activities, such as cytoplasmic streaming (1, 2), plasmodesmata function (3-5), organelle movement (6-10), cytokinesis (4, 11, 12), endocytosis (4, 5, 13-15) and targeted RNA transport (16). Plant myosins belong to two main groups of unconventional myosins: myosin XI and myosin VIII, both closely related to myosin V (17-19). The Arabidopsis myosin family contains 17 members: 13 myosin XI and four myosin VIII (19, 20). The data obtained from our research of myosins was published in two papers acknowledging BARD funding. To address whether specific myosins are involved with the motility of specific organelles, we cloned the cDNAs from neck to tail of all 17 Arabidopsis myosins. These were fused to GFP and used as dominant negative mutants that interact with their cargo but are unable to walk along actin filaments. Therefore arrested organelle movement in the presence of such a construct shows that a particular myosin is involved with the movement of that particular organelle. While no mutually exclusive connections between specific myosins and organelles were found, based on overexpression of dominant negative tail constructs, a group of six myosins (XIC, XIE, XIK, XI-I, MYA1 and MYA2) were found to be more important for the motility of Golgi bodies and mitochondria in Nicotiana benthamiana and Nicotiana tabacum (8). Further deep and thorough analysis of myosin XIK revealed a potential regulation by head and tail interaction (Avisar et al., 2011). A similar regulatory mechanism has been reported for animal myosin V and VIIa (21, 22). In was shown that myosin V in the inhibited state is in a folded conformation such that the tail domain interacts with the head domain, inhibiting its ATPase and actinbinding activities. Cargo binding, high Ca2+, and/or phosphorylation may reduce the interaction between the head and tail domains, thus restoring its activity (23). Our collaborative work focuses on the characterization of the head tail interaction of myosin XIK. For this purpose the Israeli group built yeast expression vectors encoding the myosin XIK head. In addition, GST fusions of the wild-type tail as well as a tail mutated in the amino acids that mediate head to tail interaction. These were sent to the US group who is working on the isolation of recombinant proteins and performing the in vitro assays. While stress signals involve changes in Ca2+ levels in plants cells, the cytoplasmic streaming is sensitive to Ca2+. Therefore plant myosin activity is possibly regulated by stress. This finding is directly related to the goal of the original proposal.
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Bercovier, Herve, Raul Barletta i Shlomo Sela. Characterization and Immunogenicity of Mycobacterium paratuberculosis Secreted and Cellular Proteins. United States Department of Agriculture, styczeń 1996. http://dx.doi.org/10.32747/1996.7573078.bard.
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Our long-term goal is to develop an efficient acellular vaccine against paratuberculosis based on protein antigen(s). A prerequisite to achieve this goal is to analyze and characterize Mycobacterium paratuberculosis (Mpt) secreted and cellular proteins eliciting a protective immune response. In the context of this general objective, we proposed to identify, clone, produce, and characterize: the Mpt 85B antigen and other Mpt immunoreactive secreted proteins, the Mpt L7/L12 ribosomal protein and other immunoreactive cellular proteins, Mpt protein determinants involved in invasion of epithelial cells, and Mpt protein antigens specifically expressed in macrophages. Paratuberculosis is still a very serious problem in Israel and in the USA. In the USA, a recent survey evaluated that 21.6% of the dairy herd were infected with Mpt resulting in 200-250 million dollars in annual losses. Very little is known on the virulence factors and on protective antigens of Mpt. At present, the only means of controlling this disease are culling or vaccination. The current vaccines do not allow a clear differentiation between infected and vaccinated animals. Our long-term goal is to develop an efficient acellular paratuberculosis vaccine based on Mpt protein antigen(s) compatible with diagnostic tests. To achieve this goal it is necessary to analyze and characterize secreted and cellular proteins candidate for such a vaccine. Representative Mpt libraries (shuttle plasmid and phage) were constructed and used to study Mpt genes and gene products described below and will be made available to other research groups. In addition, two approaches were performed which did not yield the expected results. Mav or Mpt DNA genes that confer upon Msg or E. coli the ability to invade and/or survive within HEp-2 cells were not identified. Likewise, we were unable to characterize the 34-39 kDa induced secreted proteins induced by stress factors due to technical difficulties inherent to the complexity of the media needed to support substantial M. pt growth. We identified, isolated, sequenced five Mpt proteins and expressed four of them as recombinant proteins that allowed the study of their immunological properties in sensitized mice. The AphC protein, found to be up regulated by low iron environment, and the SOD protein are both involved in protecting mycobacteria against damage and killing by reactive oxygen (Sod) and nitrogen (AhpC) intermediates, the main bactericidal mechanisms of phagocytic cells. SOD and L7/L12 ribosomal proteins are structural proteins constitutively expressed. 85B and CFP20 are both secreted proteins. SOD, L7/L12, 85B and CFP20 were shown to induce a Th1 response in immunized mice whereas AphC was shown by others to have a similar activity. These proteins did not interfere with the DTH reaction of naturally infected cows. Cellular immunity provides protection in mycobacterial infections, therefore molecules inducing cellular immunity and preferentially a Th1 pathway will be the best candidate for the development of an acellular vaccine. The proteins characterized in this grant that induce a cell-mediated immunity and seem compatible with diagnostic tests, are good candidates for the construction of a future acellular vaccine.
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Blum, Abraham, Henry T. Nguyen i N. Y. Klueva. The Genetics of Heat Shock Proteins in Wheat in Relation to Heat Tolerance and Yield. United States Department of Agriculture, sierpień 1993. http://dx.doi.org/10.32747/1993.7568105.bard.
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Fifty six diverse spring wheat cultivars were evaluated for genetic variation and heritability for thermotolerance in terms of cell-membrane stability (CMS) and triphenyl tetrazolium chloride (TTC) reduction. The most divergent cultivars for thermotolerance (Danbata-tolerant and Nacozari-susceptible) were crossed to develop an F8 random onbred line (RIL) population. This population was evaluated for co-segragation in CMS, yield under heat stress and HSP accumulation. Further studies of thermotolerance in relations to HSP and the expression of heterosis for growth under heat stress were performed with F1 hybrids of wheat and their parental cultivars. CMS in 95 RILs ranged from 76.5% to 22.4% with 71.5% and 31.3% in Danbata and Nacozari, respectively. The population segregated with a normal distribution across the full range of the parental values. Yield and biomass under non-stress conditions during the normal winter season at Bet Dagan dit not differ between the two parental cultivar, but the range of segregation for these traits in 138 RILs was very high and distinctly transgressive with a CV of 35.3% and 42.4% among lines for biomass and yield, respectively. Mean biomass and yield of the population was reduced about twofold when grown under the hot summer conditions (irrigated) at Bet Dagan. Segregation for biomass and yield was decreased relative to the normal winter conditions with CV of 20.2% and 23.3% among lines for biomass and yield, respectively. However, contrary to non-stress conditions, the parental cultivars differed about twofold in biomass and yield under heat stress and the population segregated with normal distribution across the full range of this difference. CMS was highly and positively correlated across 79 RILs with biomass (r=0.62**) and yield (r=0.58**) under heat stress. No such correlation was obtained under the normal winter conditions. All RILs expressed a set of HSPs under heat shock (37oC for 2 h). No variation was detected among RILs in high molecular weight HSP isoforms and they were similar to the patterns of the parental cultivars. There was a surprisingly low variability in low molecular weight HSP isoforms. Only one low molecular weight and Nacozari-specific HSP isoform (belonging to HSP 16.9 family) appeared to segregate among all RILs, but it was not quantitatively correlated with any parameter of plant production under heat stress or with CMS in this population. It is concluded that this Danbata/Nacozari F8 RIL population co-segregated well for thermotolerance and yield under heat stress and that CMS could predict the relative productivity of lines under chronic heat stress. Regretfully this population did not express meaningful variability for HSP accumulation under heat shock and therefore no role could be seen for HSP in the heat tolerance of this population. In the study of seven F1 hybrids and their parent cultivars it was found that heterosis (superiority of the F1 over the best parent) for CMs was generally lower than that for growth under heat stress. Hybrids varied in the rate of heterosis for growth at normal (15o/25o) and at high (25o/35o) temperatures. In certain hybrids heterosis for growth significantly increased at high temperature as compared with normal temperature, suggesting temperature-dependent heterosis. Generally, under normal temperature, only limited qualitative variation was detected in the patterns of protein synthesis in four wheat hybrids and their parents. However, a singular protein (C47/5.88) was specifically expressed only in the most heterotic hybrid at normal temperature but not in its parent cultivars. Parental cultivars were significantly different in the sets of synthesized HSP at 37o. No qualitative changes in the patterns of protein expression under heat stress were correlated with heterosis. However, a quantitative increase in certain low molecular weight HSP (mainly H14/5.5 and H14.5.6, belonging to the HSP16.9 family) was positively associated with greater heterosis for growth at high temperature. None of these proteins were correlated with CMS across hybrids. These results support the concept of temperature-dependent heterosis for growth and a possible role for HSP 16.9 family in this respect. Finally, when all experiments are viewed together, it is encouraging to find that genetic variation in wheat yield under chronic heat stress is associated with and well predicted by CMS as an assay of thermotolerance. On the other hand the results for HSP are elusive. While very low genetic variation was expressed for HSP in the RIL population, a unique low molecular weight HSP (of the HSP 16.9 family) could be associated with temperature dependant heterosis for growth.
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Amir, Rachel, David J. Oliver, Gad Galili i Jacline V. Shanks. The Role of Cysteine Partitioning into Glutathione and Methionine Synthesis During Normal and Stress Conditions. United States Department of Agriculture, styczeń 2013. http://dx.doi.org/10.32747/2013.7699850.bard.
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The objective of this research is to study the nature of the competition for cysteine (Cys), the first organic sulfur-containing compound, between its two main metabolites, glutathione (GSH) and methionine (Met). GSH plays a central role in protecting plants during various stresses, while Met, an essential amino acid, regulates essential processes and metabolites in plant cells through its metabolite S-adenosyl-Met. Our results, which are based on flux analysis and measurements of Met- metabolites, show that the flux towards Met synthesis is high during non-stress conditions, however the flux is significantly reduced under stress conditions, when there is high synthesis of GSH. Under oxidative stress the expression level of the regulatory enzyme of Met synthesis, cystathionine g-synthase (CGS) was reduced. By using three different systems, we have found that that GSH down regulates the expression level of CGS, thus reducing Met synthesis. We have found that this regulation occurs at the post-transcriptional level, and further studies have shown that it occurs at post-translationaly. To reveal how oxidative stress affects the flux towards Met and GSH, flux analysis was performed. We have found that the level of Met is significantly reduced, while the level of glutathione significantly increases during stress. Under stress conditions most of the glutathione is converted from GSH to GSSG (the oxidised form of glutathione). These results suggest that under normal growth conditions, Cys is channelled towards both pathways to support GSH accumulation and the synthesis of growth-essential Met metabolites. However, during oxidative stress, when a high level of GSH is required to protect the plants, the levels of GSH increase while those of CGS are reduced. This reduction leaves more Cys available for GSH synthesis under stress conditions. In addition we have also studied the effects of high GSH level on the transcriptome profile. The analysis revealed that GSH affects the expression level of many major genes coding to enzymes or proteins associated with photosynthesis, starch degradation, hormone metabolism (especially genes associated with jasmonate), biotic stress (especially genes associated with PR-proteins), cytochrome P450 genes, regulation of transcription and signaling (especially genes associated with receptor kinases and calcium). These results suggest that indeed GSH levels affect different pathways and metabolites in plants.
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Guy, Charles, Gozal Ben-Hayyim, Gloria Moore, Doron Holland i Yuval Eshdat. Common Mechanisms of Response to the Stresses of High Salinity and Low Temperature and Genetic Mapping of Stress Tolerance Loci in Citrus. United States Department of Agriculture, maj 1995. http://dx.doi.org/10.32747/1995.7613013.bard.
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The objectives that were outlined in our original proposal have largely been achieved or will be so by the end of the project in February 1995 with one exception; that of mapping cold tolerance loci based on the segregation of tolerance in the BC1 progeny population. Briefly, our goals were to 1) construct a densely populated linkage map of the citrus genome: 2) map loci important in cold and/or salt stress tolerance; and 3) characterize the expression of genes responsive to cold land salt stress. As can be seen by the preceding listing of accomplishments, our original objectives A and B have been realized, objective C has been partially tested, objective D has been completed, and work on objectives E and F will be completed by the end of 1995. Although we have yet to map any loci that contribute to an ability of citrus to maintain growth when irrigated with saline water, our very encouraging results from the 1993 experiment provides us with considerable hope that 1994's much more comprehensive and better controlled experiment will yield the desired results once the data has been fully analyzed. Part of our optimism derives from the findings that loci for growth are closely linked with loci associated with foliar Cl- and Na+ accumulation patterns under non-salinization conditions. In the 1994 experiment, if ion exclusion or sequestration traits are segregating in the population, the experimental design will permit their resolution. Our fortunes with respect to cold tolerance is another situation. In three attempts to quantitatively characterize cold tolerance as an LT50, the results have been too variable and the incremental differences between sensitive and tolerant too small to use for mapping. To adequately determine the LT50 requires many plants, many more than we have been able to generate in the time and space available by making cuttings from small greenhouse-grown stock plants. As it has turned out, with citrus, to prepare enough plants needed to be successful in this objective would have required extensive facilities for both growing and testing hardiness which simply were not available at University of Florida. The large populations necessary to overcome the variability we encountered was unanticipated and unforeseeable at the project's outset. In spite of the setbacks, this project, when it is finally complete will be exceedingly successful. Listing of Accomplishments During the funded interval we have accomplished the following objectives: Developed a reasonably high density linkage map for citrus - mapped the loci for two cold responsive genes that were cloned from Poncirus - mapped the loci for csa, the salt responsive gene for glutathione peroxidase, and ccr a circadian rhythm gene from citrus - identified loci that confer parental derived specific DNA methylation patterns in the Citrus X Poncirus cross - mapped 5 loci that determine shoot vigor - mapped 2 loci that influence leaf Na+ accumulation patterns under non-saline conditions in the BC1 population - mapped 3 loci that influence leaf Na+ accumulation paterns during salt sress - mapped 2 loci that control leaf Cl- accumulation patterns under non-saline conditions - mapped a locus that controls leaf Cl- accumulation patterns during salt stress Screened the BC1 population for growth reduction during salinization (controls and salinized), and cold tolerance - determined population variation for shoot/root ratio of Na+ and Cl- - determined levels for 12 inorganic nutrient elements in an effort to examine the influence of salinization on ion content with emphasis on foliar responses - collected data on ion distribution to reveal patterns of exclusion/sequestration/ accumulation - analyzed relationships between ion content and growth Characterization of gene expression in response to salt or cold stress - cloned the gene for the salt responsive protein csa, identified it as glutathione peroxidase, determined the potential target substrate from enzymatic studies - cloned two other genes responsive to salt stress, one for the citrus homologue of a Lea5, and the other for an "oleosin" like gene - cold regulated (cor) genes belonging to five hybridization classes were isolated from Poncirus, two belonged to the group 2 Lea superfamily of stress proteins, the others show no significant homology to other known sequences - the expression of csa during cold acclimation was examined, and the expression of some of the cor genes were examined in response to salt stress - the influence of salinization on cold tolerance has been examined with seedling populations - conducted protein blot studies for expression of cold stress proteins during salt stress and vice versa
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Nechushtai, Rachel, i Parag Chitnis. Role of the HSP70 Homologue from Chloroplasts in the Assembly of the Photosynthetic Apparatus. United States Department of Agriculture, lipiec 1993. http://dx.doi.org/10.32747/1993.7568743.bard.
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The major goal of the proposed research was to study the role of a 70-kDa heat shock cognate protein from chloroplasts (ct-HSP70) in the assembly of chlorophyll-protein complexes. The latters are mostly important in allowing photosynthesis to occur. Photosynthesis is at the heart of crop productivity and the knowledge of the biogenesis of the photosynthetic apparatus is essential to manipulate the efficiency of photosynthesis. The characterization of the function of the ct-HSP70 was planned to be studied in vitro by assaying its capability to physically interact with the thylakoid proteins and to assist their assembly into thylakoid membranes. We planned to identify regions in the light-harvesting complex protein (LHCP) that interact with the ct-HSP70 and characterize the interaction between them. We also intended to isolate cDNA clones encoding ct-HSP70, sequence them, express one of them in E. coli and use the purified protein for functional assays. The research in this BARD proposal aimed at providing insights and aid in understanding the mechanism by which plants may respond to the heat stress. Since plants often experience increased temperatures.
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Fromm, A., Avihai Danon i Jian-Kang Zhu. Genes Controlling Calcium-Enhanced Tolerance to Salinity in Plants. United States Department of Agriculture, marzec 2003. http://dx.doi.org/10.32747/2003.7585201.bard.
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The specific objectives of the proposed research were to identify, clone and characterize downstream cellular target(s) of SOS3 in Arabidopsis thaliana, to analyze the Ca2+-binding characteristics of SOS3 and the sos3-1 mutant and their interactions with SOS3 cellular targets to analyze the SOS3 cell-specific expression patterns, and its subcellular localization, and to assess the in vivo role of SOS3 target protein(s) in plant tolerance to salinity stress. In the course of the study, in view of recent opportunities in identifying Ca2+ - responsive genes using microarrays, the group at Weizmann has moved into identifying Ca2+-responsive stress genes by using a combination of aqeuorin-based measurements of cytosolic Ca and analysis by DNA microarrays of early Ca-responsive genes at the whole genome level. Analysis of SOS3 (University of Arizona) revealed its expression in both roots and shoots. However, the expression of this gene is not induced by stress. This is reminiscent of other stress proteins that are regulated by post-transcriptional mechanisms such as the activation by second messengers like Ca. Further analysis of the expression of the gene using promoter - GUS fusions revealed expression in lateral root primordial. Studies at the Weizmann Institute identified a large number of genes whose expression is up-regulated by a specific cytosolic Ca burst evoked by CaM antagonists. Fewer genes were found to be down-regulated by the Ca burst. Among the up-regulated genes many are associated with early stress responses. Moreover, this study revealed a large number of newly identified Ca-responsive genes. These genes could be useful to investigate yet unknown Ca-responsive gene networks involved in plant response to stress.
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Droby, Samir, Michael Wisniewski, Ron Porat i Dumitru Macarisin. Role of Reactive Oxygen Species (ROS) in Tritrophic Interactions in Postharvest Biocontrol Systems. United States Department of Agriculture, grudzień 2012. http://dx.doi.org/10.32747/2012.7594390.bard.
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To elucidate the role of ROS in the tri-trophic interactions in postharvest biocontrol systems a detailed molecular and biochemical investigation was undertaken. The application of the yeast biocontrol agent Metschnikowia fructicola, microarray analysis was performed on grapefruit surface wounds using an Affymetrix Citrus GeneChip. the data indicated that 1007 putative unigenes showed significant expression changes following wounding and yeast application relative to wounded controls. The expression of the genes encoding Respiratory burst oxidase (Rbo), mitogen-activated protein kinase (MAPK) and mitogen-activated protein kinase kinase (MAPKK), G-proteins, chitinase (CHI), phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS) and 4-coumarate-CoA ligase (4CL). In contrast, three genes, peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT), were down-regulated in grapefruit peel tissue treated with yeast cells. The yeast antagonists, Metschnikowia fructicola (strain 277) and Candida oleophila (strain 182) generate relatively high levels of super oxide anion (O2−) following its interaction with wounded fruit surface. Using laser scanning confocal microscopy we observed that the application of M. fructicola and C. oleophila into citrus and apple fruit wounds correlated with an increase in H2O2 accumulation in host tissue. The present data, together with our earlier discovery of the importance of H₂O₂ production in the defense response of citrus flavedo to postharvest pathogens, indicate that the yeast-induced oxidative response in fruit exocarp may be associated with the ability of specific yeast species to serve as biocontrol agents for the management of postharvest diseases. Effect of ROS on yeast cells was also studied. Pretreatment of the yeast, Candida oleophila, with 5 mM H₂O₂ for 30 min (sublethal) increased yeast tolerance to subsequent lethal levels of oxidative stress (50 mM H₂O₂), high temperature (40 °C), and low pH (pH 4). Suppression subtractive hybridization analysis was used to identify genes expressed in yeast in response to sublethal oxidative stress. Transcript levels were confirmed using semi quantitative reverse transcription-PCR. Seven antioxidant genes were up regulated. Pretreatment of the yeast antagonist Candida oleophila with glycine betaine (GB) increases oxidative stress tolerance in the microenvironment of apple wounds. ROS production is greater when yeast antagonists used as biocontrol agents are applied in the wounds. Compared to untreated control yeast cells, GB-treated cells recovered from the oxidative stress environment of apple wounds exhibited less accumulation of ROS and lower levels of oxidative damage to cellular proteins and lipids. Additionally, GB-treated yeast exhibited greater biocontrol activity against Penicillium expansum and Botrytis cinerea, and faster growth in wounds of apple fruits compared to untreated yeast. The expression of major antioxidant genes, including peroxisomal catalase, peroxiredoxin TSA1, and glutathione peroxidase was elevated in the yeast by GB treatment. A mild heat shock (HS) pretreatment (30 min at 40 1C) improved the tolerance of M. fructicola to subsequent high temperature (45 1C, 20–30 min) and oxidative stress (0.4 mol-¹) hydrogen peroxide, 20–60 min). HS-treated yeast cells showed less accumulation of reactive oxygen species (ROS) than non-treated cells in response to both stresses. Additionally, HS-treated yeast exhibited significantly greater (P≥0.0001) biocontrol activity against Penicillium expansum and a significantly faster (Po0.0001) growth rate in wounds of apple fruits stored at 25 1C compared with the performance of untreated yeast cells. Transcription of a trehalose-6-phosphate synthase gene (TPS1) was up regulated in response to HS and trehalose content also increased.