Letteratura scientifica selezionata sul tema "Effet Proteus"
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Articoli di riviste sul tema "Effet Proteus"
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Guegan, Jérôme, Stéphanie Buisine e Julie Collange. "Effet Proteus et amorçage : ces avatars qui nous influencent". Bulletin de psychologie Numéro547, n. 1 (2017): 3. http://dx.doi.org/10.3917/bupsy.547.0003.
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Yee, Nick, Jeremy N. Bailenson e Nicolas Ducheneaut. "The Proteus Effect". Communication Research 36, n. 2 (22 gennaio 2009): 285–312. http://dx.doi.org/10.1177/0093650208330254.
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Lourenco, Jeferson M., S. Claire Nunn, Eliza J. Lee, C. Robert Dove, Todd R. Callaway e Michael J. Azain. "Effect of Supplemental Protease on Growth Performance and Excreta Microbiome of Broiler Chicks". Microorganisms 8, n. 4 (27 marzo 2020): 475. http://dx.doi.org/10.3390/microorganisms8040475.
Testo completoAbstract (sommario):
One-day-old chicks were assigned one of four dietary treatments in a 2 × 2 factorial design in which the main effects were diet (adequate vs. low protein) and the addition of protease (0 vs. 200 g/1000 kg of feed). Chick performance (days 0–14) was recorded and their excreta were analyzed for short chain fatty acids, ammonia, and composition of the microbiota using 16S rRNA gene sequencing. Birds fed the low protein diet had lower body weight gain and poorer overall feed conversion ratio (FCR) (p ≤ 0.04); however, these parameters were not affected by the inclusion of protease (p ≥ 0.27). Protease inclusion did not affect any particular bacterial genus in the excreta, but it increased the total number of observed OTUs (p = 0.04) and Faith’s phylogenetic diversity (p = 0.05). Abundance of Proteus and Acinetobacter were lower in the excreta of chicks fed the low protein diet (p = 0.01). Abundance of Bacteroides was associated with poorer FCR, while Proteus was associated with improved FCR (p ≤ 0.009). Although diet had a stronger impact than protease on chick performance, both diet and protease yielded some changes in the intestinal microbiotas of the birds.
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Al-Zaidi, Omar S., e Luma abd alhady Zwein. "Effect of tannic acid on urease and protease produced from Proteus mirabilis". Journal of Biotechnology Research Center 13, n. 1 (1 gennaio 2019): 82–86. http://dx.doi.org/10.24126/jobrc.2019.13.1.573.
Testo completoAbstract (sommario):
Back ground: P.mirabilis is a gram negative bacterium, motile with its peritrichous flagella .Widely distributed in environment, especially in contaminated water and soil, Many virulence factors like LPS, urease, protease, hemolysin and biofilm formation play an important roles in the pathogenicity of P. mirabilis. Urease is a Nickel containing enzyme causes elevation of urine pH after hydrolyzing urea to ammonia and CO2 forming stones that blocks the urinary track.
Aims: The effect of tannic acid on the production of urease and protease.
Material and methods: Twenty one isolates of Proteus were collected from different sources, Clinical and animal sources all isolates were cultured on MacConkey and blood agar and identification of P. mirabilis by, Vitek -2 compact system. Determine the effect of tannic acid on the production of urease and protease.
Results: Twenty one isolates of Proteus were identified depending on Vitek-2 compact system, after identification, it turns out that only 18 isolate were P. mirabilis. All isolates were 100% able to produce urease and 72.2% isolate were able to produce protease. The addition of tannic acid showed an inhibitory effect on urease and protease production.
Conclusion: The effect of tannic acid on urease and protease depending on concentration, type of strain, incubation period, number of isolates and truculence of isolate.
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Lahelle, O. "EFFECT OF PENICILLIN ON PROTEUS VULGARIS". Acta Pathologica Microbiologica Scandinavica 25, n. 4 (18 agosto 2009): 519–28. http://dx.doi.org/10.1111/j.1699-0463.1948.tb00688.x.
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Van Der Heide, Brandon, Erin M. Schumaker, Ashley M. Peterson e Elizabeth B. Jones. "The Proteus Effect in Dyadic Communication". Communication Research 40, n. 6 (2 marzo 2012): 838–60. http://dx.doi.org/10.1177/0093650212438097.
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Bumona Zayukua, Espérance, Joachim di M’balu Umba, Charles Nzau Kusika, Thaddée Ndyanabo Masimango e Jean Grâce Ndongala Lufimpadio. "Contribution à l’analyse microbiologique des poulets, des chinchards (Trachurus trachurus) et des poissons salés vendus à Kinshasa en vue de la sensibilisation à la méthode ISO- 22000 :2005 HACCP". Journal of Animal & Plant Sciences 42.2 (29 novembre 2019): 7256–68. http://dx.doi.org/10.35759/janmplsci.v42-2.7.
Testo completoAbstract (sommario):
La qualité des denrées alimentaires est devenue une préoccupation majeure pour les consommateurs des nombreux pays. En effet, ces dernières décennies, le monde a connu des cas d’encéphalopathie spongiforme bovine (ESB) au Royaume-Uni et d’autres problèmes alimentaires plus communs associés à la Salmonella, à l’Escherichia Coli enterohaemorrhagique, de tremblante du mouton, du poulet à la dioxine, de Listériose . Cette situation a amené les consommateurs avertis à exiger que les aliments qui leurs sont vendus, soient sans danger. Les surgelés comptent parmi les aliments les plus consommés dans les grandes villes de la RD Congo. Cependant, une bonne partie de ces produits subit une rupture de la chaîne de froid telle qu’elle se détériore et devient nuisible à la santé des consommateurs. Nous savons que le poisson est une denrée très périssable et nécessite le maintien en continu de la chaîne de froid. Or, les coupures de fournitures d’énergies sont récurrentes dans notre capitale. Et cela devient un dilemme pour les consommateurs kinois. Quel est l’impact de la rupture de la chaîne de froid sur la qualité de ces surgelés vendus sur les marchés de Kinshasa? Comment le consommateur kinois est-il protégé contre les dangers alimentaires de la fourche à la fourchette? L’objectif de la présente recherche basée sur les techniques d’isolements, d’identification et de dénombrement et conformément aux normes ISO spécifiques à chaque germe, est de faire une analyse microbiologique du poulet emballé, déballé et découpé, du poisson chinchard sorti du carton, exposé sur les étals et du poisson salé local, importé et poisson du fleuve Congo vendus sur quelques marchés de Kinshasa, étudier les enjeux de la sécurité sanitaire par la méthode ISO-22000 :2005 - HACCP et proposer à l’autorité publique l’application de ces principes d’assainissement, de les vulgariser et renforcer les mesures d’hygiène alimentaire dans les grandes agglomérations du pays au profit de la santé publique (accumulation de déchets dans les rues et congestion des égouts) et lutter contre les toxi-infections alimentaires collectives (TIAC). Il ressort de notre analyse que la fréquence de contamination de micro-organismes, les Proteus arrivent en tête avec 63%, suivis des Klebsiella 41 %, les Escherichia coli 21%, les Citrobacters et Enterobacters 20 % et Salmonella spp.et Shigella 8%. ABSTRACT Food quality has become a major concern for consumers in many countries. Indeed, in recent decades, the world has experienced cases of bovine spongiform encephalopathy (BSE) in the United Kingdom and other more common nutritional problems associated with Salmonella, enterohaemorrhagic Escherichia coli, scrapie, chicken with dioxin, listeriosis. This situation has led savvy consumers to demand that the food sold to them be safe. Frozen foods are among the most consumed foods in the big cities of DR Congo. However, a good part of these products undergo a break in the cold chain as it deteriorates and becomes harmful to the health of consumers. We know that fish is a very perishable commodity and requires the continuous maintenance of the cold chain. However, cuts in energy supplies are recurrent in our capital. And this becomes a dilemma for Kinshasa consumers. What is the impact of the break in the cold chain on the quality of these frozen foods sold in the Kinshasa markets? The objective of this research, based on isolation, identification and enumeration techniques and in accordance with the ISO standards specific to each germ, is to perform a microbiological analysis of the packaged, unpacked and cut chicken of the horse mackerel cardboard, exposed on stalls and local salted fish, imported and Congo River fish sold on some markets of Kinshasa, study the stakes of the safety by the method ISO-22000: 2005 - HACCP and propose to the public authority the application of these principles of sanitation, to popularize them and to reinforce food hygiene measures in the large agglomerations of the country for the benefit of public health (accumulation of waste on the streets and sewer congestion) and to combat the toxicities Collective food infections (TIAC). This study analysis shows that the frequency of contamination of micro-organisms, Proteus, top with 63%, followed by Klebsiella 41%, Escherichia coli 21%, Citrobacters and Enterobacters 20% and Salmonella spp. And Shigella 8%.
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Fontan, Lorena, John Hatcher, David Scott, Qi Qiao, Ilkay Us, Guangyan Du, Matthew Durant et al. "Chemically Induced Degradation of MALT1 to Treat B-Cell Lymphomas". Blood 134, Supplement_1 (13 novembre 2019): 2073. http://dx.doi.org/10.1182/blood-2019-130666.
Testo completoAbstract (sommario):
MALT1 is a protease and scaffold protein involved in signal transduction to NF-κB downstream of several receptors including B-cell (BCR) and T-cell receptors (TCR). MALT1 is aberrantly activated in ABC DLBCL by mutations in upstream genes in the BCR and TLR pathways (CD79A/B, CARD11, MYD88) and is critical for proliferation and survival. Recent studies by our lab, and others, identified inhibitors of MALT1 protease activity that revealed MALT1 is therapeutically targetable in ABC DLBCL. MALT1 is also essential for CLL, MCL and certain solid tumors (most notably lung cancer and glioblastoma). A first-in-man clinical trial recently started to evaluate MALT1 protease inhibition in B-cell non-Hodgkin's lymphomas. However, chronic inactivation of MALT1 protease activity suppressed T regulatory cells in vivo in protease dead murine models causing fast progressing autoimmune disease and death. Loss of MALT1, on the other hand, has also potent anti-tumoral effects but does not lead to autoimmunity in murine models. These findings prompted us to study alternative MALT1 targeting therapeutic approaches aimed to target its scaffolding activity. We have developed a series of proteolytic targeting chimera (PROTAC) compounds against MALT1. PROTACs are bifunctional compounds that induce selective proteolysis by targeting proteins of interest to E3 ligases for directed proteosomal degradation. Our MALT1 PROTACs are based on an allosteric MALT1 inhibitor that binds reversibly to MALT1 and fused to a Cereblon (CRBN) binding moiety, with the intent of bringing the CRBN E3 ligase complex in close proximity of MALT1 and promoting its ubiquitination and proteasomal degradation. We performed structure-activity relationship analysis and studied: 1) three linker attachment points in the MALT1 binding moiety and evaluated their MALT1 enzymatic inhibitory activity and binding to MALT1; 2) the effect of distinct linker length and polarity in MALT1 degradation and, 3) compared the effect of Lenalidomide, Pomalidomide and CC-220, which have increasing CRBN affinities, as alternative CRBN-binding moieties. Six out of eighteen compounds presented higher than 50% MALT1 degradation at 1 μM compared to vehicle treated cells in a MALT1-dependent cell line, OCI-Ly3. The parental allosteric compound, on the other hand, did not affect MALT1 levels compared to vehicle treated cells and was used as a negative control for MALT1 degradation. Compounds that actively degraded MALT1 over 50% preserved selective killing of ABC DLBCL over GCB DLBCL, same as the parental MALT1 inhibitor. GI50 of active compounds in OCI-Ly3 was 2-6 μM while it was greater than 20 μM for the MALT1-independent cell line OCI-Ly1. We chose two of our most effective and selective compounds to validate MALT1 PROTACs mechanism of action. Unlike their parental MALT1 targeting allosteric compound, MALT1 PROTACs effectively degraded MALT1 in a CRBN-dependent manner as shown in a 293T-CRBN knockout cell line or in OCI-Ly3 cells by treatment with 1 μM MLN4924. MLN4924 inhibits NEDD8-activating enzyme which is essential for the CRBN complex to function. Notably, MALT1 PROTACs degraded MALT1 in OCI-Ly1 cells (FC=-2.5) and Raji cells (FC=-1.7), where MALT1 is inactive. MALT1 degradation by PROTACs was not affected by activation in Raji cells, since PMA/ionomycin treatment did not alter the effect of MALT1 PROTACs on MALT1 levels. Therefore, MALT1 PROTACs can degrade MALT1 independent of its activation state. Moreover, unlike MALT1 protease inhibitors, MALT1 PROTACs potently suppress NF-κB activation, which is dependent on MALT1 scaffolding activity, as assessed by WB of phopho and total IκB in ABC DLBCL cell lines. Our data shows that MALT1 PROTACs could be excellent agents for the treatment of ABC DLBCL and other lymphomas, providing an alternative to enzymatic targeting that might prove useful to avoid autoimmunity or overcome resistance mechanisms. Disclosures Gray: Gatekeeper, Syros, Petra, C4, B2S and Soltego.: Equity Ownership; Novartis, Takeda, Astellas, Taiho, Janssen, Kinogen, Voronoi, Her2llc, Deerfield and Sanofi.: Equity Ownership, Research Funding. Melnick:Constellation: Consultancy; Janssen: Research Funding; Epizyme: Consultancy.
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Yee, Nick, e Jeremy Bailenson. "The Proteus Effect: The Effect of Transformed Self-Representation on Behavior". Human Communication Research 33, n. 3 (luglio 2007): 271–90. http://dx.doi.org/10.1111/j.1468-2958.2007.00299.x.
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Yourassowsky, E., M. P. Van der Linden e F. Crokaert. "Antibacterial effect of meropenem and imipenem on Proteus mirabilis". Journal of Antimicrobial Chemotherapy 26, n. 2 (1990): 185–92. http://dx.doi.org/10.1093/jac/26.2.185.
Testo completoTesi sul tema "Effet Proteus"
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Dupraz, Louise. "L'effet Proteus : Performances motrices et cognitives en situation d'incorporation d'un avatar". Electronic Thesis or Diss., Chambéry, 2024. http://www.theses.fr/2024CHAMA006.
Testo completoAbstract (sommario):
La représentation corporelle, étonnamment plastique, peut présenter des déviations importantes par rapport aux frontières du corps biologique. Les paradigmes d'incorporation illustrent cette plasticité. Il est possible, par exemple, d'intégrer à la représentation corporelle une main en caoutchouc, ou de faire émerger un sentiment d'incorporation pour un avatar d'âge différent de celui du participant. L'incorporation d'un avatar s'accompagne de conséquences perceptives, cognitives et comportementales, ces dernières ayant largement été étudiées dans le cadre de l'effet Proteus. Par exemple, l'incorporation d'un avatar attractif, plutôt qu'un avatar peu attractif, conduit les participants à se montrer plus confiants et extravertis aux cours des échanges, conformément aux stéréotypes relatifs à la beauté. Ce phénomène de conformisme aux stéréotypes associés à l'avatar incorporé a été discuté au regard de différents processus : processus d'auto-perception, effet d'amorçage, processus d'incorporation, adhésion aux stéréotypes. Toutefois, les arguments empiriques sont insuffisants pour comprendre précisément les mécanismes sous-jacents à l'apparition du phénomène. Un premier objectif de ce travail de thèse était de confirmer l'intervention d'un mécanisme additionnel à celui d'un effet d'amorçage situationnel direct dans l'apparition de l'effet Proteus. Conformément à l'hypothèse, les études ont démontré le phénomène au-delà de l'activation des stéréotypes associés à l'avatar. Un second objectif était de tester le rôle causal du processus d'incorporation sur l'apparition de l'effet Proteus. Contrairement à ce qui était attendu, un effet Proteus a été retrouvé indépendamment du fait de considérer le corps de l'avatar comme étant sien. Les résultats sont en faveur de l'apparition du phénomène dès lors qu'une relation identitaire est instaurée avec l'avatar. Un dernier objectif visait à examiner la contribution d'un changement de perception de soi dans l'apparition de l'effet Proteus. Les études n'ont toutefois pas permis d'en attester. En somme, le présent travail de thèse apporte des éléments de compréhension de l'effet Proteus et incite à poursuivre la démarche d'approfondissement théorique vers l'étude des mécanismes relatifs à la perception de soi implicite. Améliorer la compréhension des mécanismes sous-jacents au phénomène offre des perspectives dans le domaine de la prise en charge thérapeutique et de la prévention des risques psycho-sociauxBody representation is surprisingly plastic and can deviate from the boundaries of the biological body. Embodiment paradigms illustrate this plasticity. For example, it is possible to integrate a rubber hand in the body representation, or to elicit a sense of embodiment for an avatar of a different age from the participant. The embodiment of an avatar is associated with perceptual, cognitive, and behavioral consequences, which have been extensively studied in the context of the Proteus effect. For instance, the embodiment of an attractive avatar, compared to an unattractive one, led participants to be more confident and extroverted during exchanges, in line with stereotypes related to beauty. In the literature, this conformism to the stereotypes associated with the avatar has been discussed regarding different processes: self-perception process, priming effect, embodiment process, stereotype endorsement. However, empirical arguments are still insufficient to provide a precise explanation of the mechanisms underlying this phenomenon. A first objective of this thesis was to confirm the involvement of an additional mechanism to that of a direct priming effect in the occurrence of the Proteus effect. In line with the hypothesis, the studies demonstrated that the phenomenon occurs beyond the mere activation of stereotypes associated with the avatar. A second objective was to investigate the causal role of embodiment on the Proteus effect. Contrary to expectations, a Proteus effect was observed regardless of considering the avatar's body as one's own. The results support the occurrence of the phenomenon as long as an identity relationship is established with the avatar. A last objective was to examine the contribution of a self-perception change in the occurrence of the Proteus effect. However, the studies did not provide any conclusive evidence for this hypothesis. In summary, the present thesis provides new insights into the Proteus effect and suggests further theoretical investigation into the implicit self-perception mechanisms. A better understanding of the mechanisms underlying the Proteus effect promises perspectives in clinical practice and in prevention of psycho-social risks
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Chilukuri, Lakshmi N. "The effect of pressure on DNA-binding proteins from piezosensitive and piezophilic bacteria /". Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1998. http://wwwlib.umi.com/cr/ucsd/fullcit?p3035908.
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Liu, Ziqiang. "Molecular analysis and functional characterization of Nucleosome Assembly Protein 1 (NAP1) family proteins in plants". Université Louis Pasteur (Strasbourg) (1971-2008), 2008. http://www.theses.fr/2008STR13132.
Testo completoAbstract (sommario):
Eukaryotic genomes are packaged into chromatin, a regularly repeated structure whose fundamental building block is the nucleosome. Each nucleosome core particle is composed of a histone octamer consisting of two molecules each of the core histones H2A, H2B, H3, and H4, around which approximately 146–147 bp of DNA is wrapped. The assembly of nucleosome is the first step of chromatin assembly which is important for the chromatin structure affecting a broad ranges of biological events including DNA replication, repair, recombination, transcription, cell differentiation, proliferation, and organism development, and is fulfilled with the help of histone chaperones, which are important for the organization and dynamics of chromatin templates, and are involved in the storage, translocation to the nucleus and exchange of histones and their deposition onto the DNA for replication-dependent chromatin assembly. [. . . ].
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Praneet, Opanasopit. "Effect of Serum Mannan Binding Protein on Tissue Disposition of Glycosylated Proteins and Liposomes". 京都大学 (Kyoto University), 2002. http://hdl.handle.net/2433/150103.
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Montalvo, Acosta Joel José. "Computational approaches to molecular recognition : from host-guest to protein-ligand binding". Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAF051/document.
Testo completoAbstract (sommario):
La reconnaissance moléculaire est un problème très intéressant et surtout un défi actuel pour la chimie biophysique. Avoir des prévisions fiables sur la reconnaissance spécifique entre les molécules est hautement prioritaire, car il fournira un aperçu des problèmes fondamentaux et suscitera des applications technologiques pertinentes. La thèse présentée ici est centrée sur une analyse quantitatif de la reconnaissance moléculaire en solution pour la liaison l'hôte-invité, la liaison protéine-ligand et la catalyse. Le cadre de la mécanique statistique utilisé pour décrire l'état de la technique de liaison récepteur-ligand est un point d'inflexion pour le développement de nouvelles méthodes améliorées. En fait, un modèle très performant et précis a été obtenu pour l'analyse de la liaison hôte-invité. Enfin, les modèles présentés ont été utilisés comme outils prédictifs fiables pour la découverte de nouvelles entités chimiques destinées à améliorer la catalyse en solutionMolecular recognition is a very interesting problem, and foremost, a current challenge for biophysical chemistry. Having reliable predictions on the specific recognition between molecules is highly priority as it will provide an insight of fundamental problems and will raise relevant technological applications. The dissertation presented here is centered on a quantitative analysis of molecular recognition in solution for host-guest, protein-ligand binding and catalysis. The statistical mechanics framework used to describe the state-of-the-art for receptor-ligand binding is an inflection point for the developing of new improved and methods. In fact, a highly performanced and accurate model was obtained for the analysis of host-guest binding. Finally, the presented models were used as a reliable predictive tools for discovering new chemical entities for enhance catalysis in solution
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Rassadi, Roozbeh. "The effect of stress on nuclear protein transport : classical nuclear protein transport versus the nuclear transport of heat shock proteins". Thesis, McGill University, 1999. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33476.
Testo completoAbstract (sommario):
The stress response is conserved among eukaryotes and affects different cellular functions including protein transport. Here, we have investigated the effect of different types of stress on classical nuclear protein import as well as nuclear import of Ssa4p family of heat shock proteins in Saccharomyces cerevisiae.Under normal conditions, Aequorea victoria green fluorescent protein (GFP), carrying a classical nuclear localization sequence (cNLS-GFP) is nuclear. However, cNLS-GFP equilibrates throughout the cell upon exposure to heat, ethanol, H2O2 or starvation. Redistribution of the small GTPase Gsp1p, a soluble nuclear transport factor, correlates with cNLS-GFP equilibration. This suggests that a collapse of the Gsp1p gradient underlies the inhibition of classical nuclear protein import. In contrast to cNLS-GFP, the cytoplasmic heat shock protein Ssa4p accumulates in nuclei when classical nuclear import is inhibited. The N-terminal 236 amino acid residues of Ssa4p are sufficient for nuclear localization of Ssa4p-GFP upon heat and ethanol stress. The nuclear localization of Ssa4p(1--236)-GFP requires components of Gsp1-GTPase system, but is independent of Srp1p, the cNLS receptor.
Ssa4p(16--642)-GFP accumulates in nuclei of starving cells, mediated by a hydrophobic stretch of amino acid residues in its N-terminal domain. This nuclear localization is reversible upon addition of fresh medium and its export is sensitive to oxidants and temperature-dependent.
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Jugniot, Natacha. "Molecular imaging of serine protease activity-driven pathologies by magnetic resonance". Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0141/document.
Testo completoAbstract (sommario):
Ce travail porte sur le développement de sondes peptidiques pour le suivi de la protéolyse par spectroscopie de résonance paramagnétique électronique (RPE) et pour l'imagerie in vivo par résonance magnétique rehaussée de l’effet Overhauser (OMRI). Plus précisément, ce travail étudie pour la première fois une famille d’agents d’imagerie appelée « nitroxyde à déplacement de raies spectrales » spécifique d’activités enzymatiques. L'activité protéolytique, entraînant un décalage de 5 G dans les constantes de couplages hyperfins, permet une quantification individuelle des espèces substrat et produit par RPE et une excitation sélective par OMRI. Trois substrats ont été élaborés, montrant une spécificité enzymatique pour l’élastase du neutrophile (NE) (MeO-Suc-Ala-Ala-Pro-Val-Nitroxyde & Suc-Ala-Ala-Pro-Val-Nitroxyde), et pour la chymotrypsine et la cathepsine G (Suc-Ala-Ala-Pro-Phe-Nitroxyde). Les constantes enzymatiques ont montré de bonnes valeurs avec globalement, Km = 28 ± 25 µM et kcat = 19 ± 3 s-1. Ex vivo, l’utilisation des substrats NE en OMRI a révélé un contraste élevé dans les lavages broncho-alvéolaires de souris sous stimulus inflammatoire. Les rehaussements de signaux IRM sont en corrélation avec la sévérité de l’inflammation. L'irradiation à la fréquence RPE de 5425,6 MHz a permis d'accéder à la bio-distribution des substrats in vivo et pourrait ainsi servir d’outil diagnostic. Les perspectives à moyen terme de ce travail reposent sur le développement de l’OMRI à très faibles champs magnétiques en vue d’une application chez l’hommeThis work focuses on substrate-based probes for proteolysis monitoring by Electron Paramagnetic Resonance spectroscopy (EPR) and for in vivo imaging by Overhauser-enhanced Magnetic Resonance (OMRI). More precisely, this work investigates for the first time a family of MRI agents named “line-shifting nitroxide” specific for proteolytic activities. Proteolytic action results in a shift of 5 G in EPR hyperfine coupling constants allowing individual quantification of substrate and product species by EPR and selective excitation by OMRI. Three substrates were worked out, showing enzymatic specificity for neutrophil elastase (MeO-Suc-Ala-Ala-Pro-Val-Nitroxide & Suc-Ala-Ala-Pro-Val-Nitroxide), and for Chymotrypsin/Cathepsin G (Suc-Ala-Ala-Pro-Phe-Nitroxide). Enzymatic constants were remarkably good with globally Km = 28 ± 25 µM and kcat = 19 ± 3 s-1. Ex vivo, the use of NE substrates in OMRI revealed a high contrast in bronchoalveolar lavages of mice under inflammatory stimulus. MRI signal enhancements correlate with the severity of inflammation. Irradiation at the RPE frequency of 5425.6 MHz provided access to the bio-distribution of substrates in vivo and could thus serve as a diagnostic tool. The medium-term perspectives of this work are based on the development of OMRI with very low magnetic fields for human application
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Odunuga, Odutayo Odutola. "Molecular characterization of the tetratricopeptide repeat-mediated interactions of murine stress-inducible protein 1 with major heat shock proteins". Thesis, Rhodes University, 2003. http://hdl.handle.net/10962/d1007724.
Testo completoAbstract (sommario):
Murine stress-inducible protein 1 (mSTI1) is a co-chaperone that is homologous with the human heat shock protein 70 (Hsp70)/heat shock protein 90 (Hsp90)-organizing protein (Hop). The two proteins are homologues of the highly conserved stress-inducible protein 1 (STI1) family of co-chaperones. The STI1 proteins interact directly and simultaneously at some stage, with Hsp70 and Hsp90 in the formation of the hetero-multi-chaperone complexes that facilitate the folding of signal transducing kinases and functional maturation of steroid hormone receptors. The interactions of mSTI1 with both Hsp70 and Hsp90 is mediated by a versatile structural protein-protein interaction motif, the tetratricopeptide repeat (TPR). The TPR motif is a degenerate 34-amino acid sequence a-helical structural motif found in a significant number of functionally unrelated proteins. This study was aimed at characterizing the structural and functional determinants in the TPR domains of mSTI1 responsible for binding to and discriminating between Hsp70 and Hsp90. Guided by data from Hop's crystal structures and amino acid sequence alignment analyses, various biochemical techniques were used to both qualitatively and quantitatively characterize the contacts necessary for the N-terminal TPR domain (TPR1) of mSTI1 to bind to the C-terminal EEVD motif of heat shock cognate protein 70 (Hsc70) and to discriminate between Hsc70 and Hsp90. Substitutions in the first TPR motif of Lys⁸ or Asn¹² did not affect binding of mSTI1 to Hsc70, while double substitution of these residues abrogated binding. A substitution in the second TPR motif of Asn⁴³ lowered but did not abrogate binding. Similarly, a deletion in the second TPR motif coupled with a substitution of Lys⁸ or Asn¹² reduced but did not abrogate binding. Steady state fluorescence and circular dichroism spectroscopies revealed that the double substitution of Lys⁸ and Asn¹² resulted in perturbations of inter-domain interactions in mSTl1. Together these results suggest that mSTI1-Hsc70 interaction requires a network of electrostatic interactions not only between charged residues in the TPR1 domain of mSTI1 and the EEVD motif of Hsc70, but also outside the TPR1 domain. It is proposed that the electrostatic interactions in the first TPR motif collectively made by Lys⁸ and Asn¹² define part of the minimum interactions required for successful mSTI1-Hsc70 interaction. In the first central TPR domain (TPR1A), single substitution of Lys³°¹ was sufficient to abrogate the mSTI1-Hsp90 interaction. Using a truncated derivative of mSTI1 incapable of binding to Hsp90, residues predicted by crystallographic data to determine Hsp70 binding specificity were substituted in the TPR1 domain. The modified protein had reduced binding to Hsc70, but showed significant binding capacity for Hsp90. In contrast, topologically equivalent substitutions on a truncated derivative of mSTI1 incapable of binding to Hsc70 did not confer Hsc70 specificity on the TPR2A domain. These data suggest that binding of Hsc70 to the TPR1 domain is more specific than binding of Hsp90 to the TPR2A domain. In addition, residues C-terminal of helix A in the second TPR motif of mSTI1 were shown to be important in determining specific binding to Hsc70. Binding assays using surface plasmon resonance spectroscopy showed that the affinities of binding of mSTI1 to Hsc70 and Hsp90 were 2 μM and 1.5 μM respectively. Preliminary in vivo studies revealed differences in the dynamics of binding of endogenous and exogenous recombinant mSTI1 with Hsc70 and Hsp90. The outcome of this study poses serious implications for the mechanisms of mSTI1 interactions with Hsc70 and Hsp90 in the cell.
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Delgado, Malcom Arturo. "Biochemical Study of Engineered Fluorescent Proteins as Calcium Sensors and the Effect of Calcium and PH in Cell Reproduction and Protein Expression". Digital Archive @ GSU, 2009. http://digitalarchive.gsu.edu/chemistry_theses/23.
Testo completoAbstract (sommario):
Calcium plays important roles in both eukaryotic and prokaryotic cells. Its actions help to stabilize cell synthesis, growth and development. In this thesis, studies have been completed to determine effects of calcium and pH on bacterial cell growth and protein expression using the bacterial cell strain E.coli BL21(DE3). Our studies demonstrated the addition of calcium addition in the media does not affect growth but increases protein expression, while reducing the pH from 7 to 4 through the addition of 10mM EGTA in LB media inhibits both. Additionally, we report studies on the design, expression, and purification of fluorescent mCherry variants and their differences in their optical properties, including: extinction coefficients , quantum yields and pKa values. Also, we report progress in the crystallization of two GFP calcium sensors: G1 and D1, using 13 and15% PEG 4000 and 3350 respectively in 50mM HEPES buffer (pH 6.8-7.0) in an effort to optimize crystallization.
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Li, Jiaxie. "Effects of genetic variants of k-Casein and b-lactoglobulin on heat denaturation of milk proteins and formation of protein complex". Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=27367.
Testo completoAbstract (sommario):
This study was based on the 462 milk samples collected from approximately 2000 cows registered in Dairy Herd Analysis Service (DHAS). Milk samples from fresh milks were phenotyped by gel electrophoresis. Milk samples were selected according to the nine possibilities of phenotype combination of $ kappa$-casein AA, AB, BB and $ beta$-lactoglobulin AA, AB and BB. Selected milk samples from fresh milks were heated at 25$ sp circ$C, 60$ sp circ$C, 70$ sp circ$C, 80$ sp circ$C and 90$ sp circ$C, respectively. Whole casein and whey protein were separated by adjusting the pH to 4.6. Quantitative determination of milk protein were performed by reverse-phase HPLC. Whole casein was separated to $ kappa$-casein ($ kappa$-Cn), $ beta$-casein ($ beta$-Cn) and $ rm alpha sb{s}$-casein ($ rm alpha sb{s}$-Cn). Whey protein was separated as immunoglobulin (Ig), bovine serum albumin (BSA), $ alpha$-lactalbumin ($ alpha$-La) and $ beta$-lactoglobulin ($ beta$-Lg). Individual milk protein fraction was quantitatively determined by relative peak area and their ratios to whey protein or casein. The denaturation of individual milk protein at different heating temperature was investigated. (Abstract shortened by UMI.)
Libri sul tema "Effet Proteus"
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R, Means Anthony, a cura di. Calcium regulation of cellular function. New York: Raven Press, 1995.
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R, Means Anthony, a cura di. Advances in second messenger and phosphoprotein research. New York: Raven Press, 1995.
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3
Hettiarachchy, Navam S. Food proteins and peptides: Chemistry, functionality, interactions, and commercialization. Boca Raton, FL: Taylor & Francis, 2012.
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Kapelner, Rachel A. Effect of Protein Charge and Charge Distribution on Protein-Based Complex Coacervates. [New York, N.Y.?]: [publisher not identified], 2021.
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5
M, Sanders Lynda, e Hendren R. Wayne, a cura di. Protein delivery: Physical systems. New York: Plenum Press, 1997.
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Onaolapo, Josiah Ademola. The effect of R-plasmid RP1 on the properties of Proteus mirabilis. Birmingham: Aston University. Department of Pharmaceutical Sciences, 1986.
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Valkonen, Mari. Functional studies of the secretory pathway of filamentous fungi: The effect of unfolded protein response on protein production. Espoo [Finland]: VTT Technical Research Centre of Finland, 2003.
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International Symposium on Calcium-Binding Proteins in Health and Disease (6th 1988 Nagoya-shi, Japan). Calcium protein signaling. A cura di Hidaka Hiroyoshi 1938-. New York: Plenum Press, 1989.
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André, Haeberli, a cura di. Human protein data. Weinheim: Wiley-VCH, 1998.
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Rihal, Parmjit Kaur. Investigation into the effect of free radicals on proteins. Uxbridge: Brunel University, 1986.
Cerca il testo completoCapitoli di libri sul tema "Effet Proteus"
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Opp, Karl-Dieter, e Wolfgang Roehl. "Sanktionen und Protest". In Der Tschernobyl-Effekt, 129–68. Wiesbaden: VS Verlag für Sozialwissenschaften, 1990. http://dx.doi.org/10.1007/978-3-663-09636-8_6.
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Opp, Karl-Dieter, e Wolfgang Roehl. "Ein Erklärungsmodell Politischen Protests". In Der Tschernobyl-Effekt, 5–25. Wiesbaden: VS Verlag für Sozialwissenschaften, 1990. http://dx.doi.org/10.1007/978-3-663-09636-8_1.
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Opp, Karl-Dieter, e Wolfgang Roehl. "Interne Anreize von Protest: Normen, Aggressionsbereitschaft und der Unterhaltungswert von Protest". In Der Tschernobyl-Effekt, 101–10. Wiesbaden: VS Verlag für Sozialwissenschaften, 1990. http://dx.doi.org/10.1007/978-3-663-09636-8_4.
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Opp, Karl-Dieter, e Wolfgang Roehl. "Ressourcen als Determinanten Politischen Protests". In Der Tschernobyl-Effekt, 111–28. Wiesbaden: VS Verlag für Sozialwissenschaften, 1990. http://dx.doi.org/10.1007/978-3-663-09636-8_5.
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Opp, Karl-Dieter, e Wolfgang Roehl. "Soziale Netzwerke und Politischer Protest". In Der Tschernobyl-Effekt, 169–216. Wiesbaden: VS Verlag für Sozialwissenschaften, 1990. http://dx.doi.org/10.1007/978-3-663-09636-8_7.
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Opp, Karl-Dieter, e Wolfgang Roehl. "Unzufriedenheit mit der Nutzung der Atomenergie, Politische Entfremdung, Einfluss und Protest". In Der Tschernobyl-Effekt, 59–100. Wiesbaden: VS Verlag für Sozialwissenschaften, 1990. http://dx.doi.org/10.1007/978-3-663-09636-8_3.
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Micsonai, András, Éva Bulyáki e József Kardos. "BeStSel: From Secondary Structure Analysis to Protein Fold Prediction by Circular Dichroism Spectroscopy". In Methods in Molecular Biology, 175–89. New York, NY: Springer US, 2020. http://dx.doi.org/10.1007/978-1-0716-0892-0_11.
Testo completoAbstract (sommario):
Abstract Far-UV circular dichroism (CD) spectroscopy is a classical method for the study of the secondary structure of polypeptides in solution. It has been the general view that the α-helix content can be estimated accurately from the CD spectra. However, the technique was less reliable to estimate the β-sheet contents as a consequence of the structural variety of the β-sheets, which is reflected in a large spectral diversity of the CD spectra of proteins containing this secondary structure component. By taking into account the parallel or antiparallel orientation and the twist of the β-sheets, the Beta Structure Selection (BeStSel) method provides an improved β-structure determination and its performance is more accurate for any of the secondary structure types compared to previous CD spectrum analysis algorithms. Moreover, BeStSel provides extra information on the orientation and twist of the β-sheets which is sufficient for the prediction of the protein fold. The advantage of CD spectroscopy is that it is a fast and inexpensive technique with easy data processing which can be used in a wide protein concentration range and under various buffer conditions. It is especially useful when the atomic resolution structure is not available, such as the case of protein aggregates, membrane proteins or natively disordered chains, for studying conformational transitions, testing the effect of the environmental conditions on the protein structure, for verifying the correct fold of recombinant proteins in every scientific fields working on proteins from basic protein science to biotechnology and pharmaceutical industry. Here, we provide a brief step-by-step guide to record the CD spectra of proteins and their analysis with the BeStSel method.
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Opp, Karl-Dieter, e Wolfgang Roehl. "Der Tschernobyl-Effekt: Die Wirkung Kritischer Ereignisse auf die Mobilisierung Politischen Protests". In Der Tschernobyl-Effekt, 27–57. Wiesbaden: VS Verlag für Sozialwissenschaften, 1990. http://dx.doi.org/10.1007/978-3-663-09636-8_2.
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Opp, Karl-Dieter, e Wolfgang Roehl. "Resümee: Die Überprüfung Eines Kernmodells Politischen Protests und Probleme für die Forschung". In Der Tschernobyl-Effekt, 217–25. Wiesbaden: VS Verlag für Sozialwissenschaften, 1990. http://dx.doi.org/10.1007/978-3-663-09636-8_8.
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Garnier, P., B. Savalle, G. Miranda e J. P. Pélissier. "Effect of Technological Treatments of Milk on Gastric Digestion". In Milk Proteins, 237. Heidelberg: Steinkopff, 1989. http://dx.doi.org/10.1007/978-3-642-85373-9_36.
Testo completoAtti di convegni sul tema "Effet Proteus"
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Kandori, Ayumu, Masato Takahashi, Chawan Koopipat e Norimichi Tsumura. "Proteus effect in vertical jumping wearing a head-mounted display". In 3D Image Acquisition and Display: Technology, Perception and Applications, JTh2A.10. Washington, D.C.: Optica Publishing Group, 2024. http://dx.doi.org/10.1364/3d.2024.jth2a.10.
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Foster, D., B. Schach, M. Rudinsky, K. Berkner, A. Kumar, C. Sprecher, F. Hagen e E. W. bavie. "The Effect of Changes in the Leader Sequence of Human Protein C on Biosynthetic Processing and Gamma-Carboxylation". In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643648.
Testo completoAbstract (sommario):
Protein C is the precursor to a serine protease in plasma which contains gamma-carboxy glutamic acid and functions as a potent anticoagulant. Protein C shows considerable structural homology with the other vitamin K-dependent coagulation factors including prothrombin, factor VII, factor IX and factor X. This homology includes the putative pro-peptide region of the prepro leader sequences for these proteins, as well as the leader sequences for gamma-carboxylated proteins from bone. Deletion mutants have been constructed in the cDNA for human protein C in order to test the possibility that the pro-peptide portion of the 42 amino acid leader sequence serves as a molecular signal for gamma-carboxylation. Accordingly, these mutants contain the pre-peptide (hydrophobic leader) plus portions of the pro-peptide at the amino terminus of the light chain. The mutant proteins were expressed in carboxylation-competent mammalian cells and analyzed by barium citrate precipitation and N-terminal amino acid sequencing. These studies have shown that deletions in the pro-peptide region interfere with gamma-carboxylation and removal of the pro-peptide. Deletion of residues −1 through −12 had little effect on the carboxylation or secretion. Deletion of −1 through −17 completely abolished gamma-carboxylation, but had no measurable effect on secretion. Amino terminal sequence analysis of the latter mutant showed that the light chain began with Thr-Pro-Ala-Pro... This corresponds to a sequence in the prepro leader starting at −24. This indicates that the signal peptidase cleavage site for human protein C is between residues −25 and −24 and removal of the pro-peptide had been blocked by the deletion.
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Albe Slabi, Sara, Christelle Mathé, Mbalo Ndiaye, Odile Mesieres e Romain Kapel. "Combined effect of extraction and purification conditions on yield, composition, functional and structural properties of lupin proteins". In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/rcdt7862.
Testo completoAbstract (sommario):
The growing global population combined with the socio-economic changes leads to the increase of the demand of plant proteins for human nutrition. In recent years, many studies has been aimed at developing new high-quality and functional plant-based protein food. Lupin being a widely cultivated legume crop is one of the most promising alternative source of proteins for human nutrition. However, the scientific knowledge of the production process of proteins from lupin meal is still very scarce.In this work, different conditions of extraction and purification were evaluated for production of lupin protein isolates. The results showed that the extraction yield was comparable between acidic and alkaline pH (37% vs 40-45%) and the extracted proteins were principally composed of globulins. This finding was astonishing regarding the selective extraction of albumins in acidic pH previously reported for other plant protein sources. The ionic strength negatively impacted the protein extractability at pH 2, whereas no significant differences were observed between extraction at 20 to 50°C.The selected extraction conditions (pH 2 and 7) combined with purification by isoelectric precipitation or ultrafiltration process generated the isolate grade products. Further structural characterization of isolates revealed a partial denaturation of lupin proteins extracted under acidic pH resulting in low protein solubility at pH 6-7 (10-50%), loss in secondary structure, low thermal stability, and formation of aggregates. However, these modifications did not significantly impact the foaming and emulsifying properties of proteins. The obtained results highlighted the original and previously not described behaviors of lupin proteins observed during the isolation process. For the first time the combined effect of extraction and purification conditions on the process performances and the quality of producing proteins was shown. The presented conclusions may help to better characterize lupin proteins and valorize lupin meal as a source of plant proteins in food industry.
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Foster, D., B. Schach, M. Rudisky, K. Berkner, A. Kumar, A. Kumar, C. Sprecher, F. Hagen e E. W. Davie. "The Effect of Changes in the Leader Sequence of Human Protein C on Biosynthetic Processing and Gamma-Carboxylation". In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643993.
Testo completoAbstract (sommario):
Protein C is the precursor to a serine protease in plasma which contains gamma-carboxy glutamic acid and functions as a potent anticoagulant. Protein C shows considerable structural homology with the other vitamin K-dependent coagulation factors including prothrombin, factor VII, factor IX and factor X. Sequence analysis ofthe cDNAs for these proteins has revealedthe presence of a prepro leader sequence that contains a pre sequence or hydrophobic signal sequence and a propeptide containing a number of highly conserved amino acids. The pre region is removed from thegrowing polypeptide chain by signal peptidase, while the pro region is subsequently removed from the protein prior to secretion. Deletion mutants have been constructed in the propeptide portion of the cDNAfor human protein C in order to test the possibility that the propeptide portion of the 42 amino acid leader sequence serves as a molecular signal for gamma-carboxylation.Accordingly, these mutants containthe pre-peptide (hydrophobic leader) plusportions of the pro-peptide at the amino terminus of the light chain. These deletions include the removal of 4, 9, 12, 15, 16 or 17 amino acids from the carboxyl end of the leader sequence of 42 amino acids. The mutant proteins were expressed in carboxylation-competent mammalian cells and were then examined by Western blotting, barium citrate adsorption and precipitation, amino acid sequence analysis, and biological activity and compared with the native protein present in normal plasma. These studies have shown that deletions inthe pro-peptide region interfere with gamma-carboxylation and removal of the pro-peptide. Deletion of residues -1 through -12 had little effect on the carboxylationor secretion. Deletion of -1 through -17 completely abolished gamma-carboxylation, but had no measurable effect on secretion.Amino terminal sequence analysis of thelatter mutant showed that the light chainbegan with Thr-Pro-Ala-Pro... This corresponds to a sequence in the prepro leader starting at -24. This indicates that the signal peptidase cleavage site for human protein C is between residues -25 and -24 and removal of the pro-peptide had been blocked by the deletion.Furthermore, during biosynthesis and secretion, the amino-terminal region of the propeptide (residues from about -12 through -17) are important for carboxylation of protein C, while the carboxyl-terminal portion of the peptide (residues -1 through -4) are important for the removal of the proleader sequence by proteolytic processing.
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Shulgina, I. S., S. N. Yakubitskiy, A. A. Sergeev, K. A. Titova, M. B. Borgoyakova, E. V. Starostina, L. I. Karpenko e S. N. Shchelkunov. "EFFECT OF THE ATI GENE DELETION ON PATHOGENICITY AND IMMUNOGENICITY OF THE VACCINIA VIRUS". In X Международная конференция молодых ученых: биоинформатиков, биотехнологов, биофизиков, вирусологов и молекулярных биологов — 2023. Novosibirsk State University, 2023. http://dx.doi.org/10.25205/978-5-4437-1526-1-268.
Testo completoAbstract (sommario):
Among nonvirion proteins of the vaccinia virus (VACV), a 94-kDa protein (a truncated form of ATI protein) is synthesized in the largest quantity. This protein is a major immunogen upon infection of humans and animals with VACV. Meanwhile, antibodies specific to this protein are not virus-neutralizing. The present study aimed to investigate the effect of production of this protein on manifestation of pathogenicity and immunogenicity of VACV in a mouse model.
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Dosković, Vladimir, Snežana Bogosavljević-Bošković, Zdenka Škrbić, Božidar Milošević, Miloš Lukić, Simeon Rakonjac e Veselin Petričević. "EFFECT OF PROTEASE ADDED IN FOOD AND SEX ON CHICKEN MEAT CLASESS". In 1st International Symposium on Biotechnology. University of Kragujevac, Faculty of Agronomy, 2023. http://dx.doi.org/10.46793/sbt28.223d.
Testo completoAbstract (sommario):
The effects of feeding low dietary crude protein with supplemental protease and sex on the weight and percent yields of individual meat classes in broiler chickens of hybrid Cobb 500 were investigated. A total of 300 day-old broiler chicks were fed with one of the following three experimental diets: control group (C), the experimental group I (E-I) contained 4% less crude protein than the control (C) and were supplemented with protease (Ronozyme Pro Act) at a concentration of 200mg/kg feed and the experimental group II (E-II) contained 6% less crude protein and were supplemented with protease (Ronozyme Pro Act) at a concentration of 300mg/kg feed. Supplementation of protease to diets had no significant effects on weights of individual meat classes (P>0.05), as well as the percentage of meat classes, and the only differences were manifested between E-I and E-II (P<0.05, female broilers from the E-I group were had a higher percentage of class I meat and a lower percentage of class III meat compared to females from the E-II group). The effect of sex was manifested in the weights of all meat classes and the percentage of class I meat and class III meat (P<0.05).
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Church, W., T. Messier, P. Howard, J. Amiral, D. Meyer e K. Mam. "A SHARED EPITOPE ON HUMAN PROTEIN C, FACTOR X, FACTOR VII, AND PROTTOBIN DEFINED BY A MONOCLONAL ANTIBODY". In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643937.
Testo completoAbstract (sommario):
A monoclonal antibody prepared against hunan protein C (HPC) was found to react with several other vitamin K-dependent blood proteins. Using a competitive inhibition solid-phase radioinminoassay with HPC, binding of 125I-HPC to the antibody was inhibited by purified prothrombin, Factor X, and Factor VII in addition to protein C. Other vitamin K-dependent proteins including Factor IX, protein S, and bone-GLA protein did not compete for binding of 125I-HPC to the antibody. The effect of calciun ion on the binding of antibody to 125I-HPC was examined in a solid-phase imnunoassay system with the antibody bound to rabbit anti-mouse inminoglobulin adsorbed to microtiter plates. In the presence of 5 mM calciun ion, radiolabeled protein C did not bind to the antibody; radiolabeled protein C did bind, however, in the presence of 5 nM EDTA suggesting that the epitope is expressed only after removal of calciun ion. The antibody bound to prothrombin and to decarboxylated prothrombin after adsorption of the antigens onto nitrocellulose indicating that the presence of GLA was not required for antibody binding. Iimunoblotting of proteins which were reduced, the peptides separated by SDS-PAGE, and transferred to nitrocellulose showed that the antibody reacts with a determinant found on the light chains of protein C and Factor X and with prothrombin Fragment 1. Comparison of the protein sequences of protein C light chain, Factor X light chain, Factor VII, and prothrombin Fragment 1 identified a segment of amino acid sequence that is highly conserved in all four proteins and might contain the antigenic site. The monoclonal antibody thus defines an antigenic determinant which is masked by calcium ion and is found on the surface of several related, yet different coagulation proteins. This antibody should prove useful in understanding the evolutionary relationships amongst the vitamin K-dependent proteins and also in understanding the effect of calcium ion on the structure of protein C, Factor X, prothrombin, Factor VII and possibly other related proteins. (Supported by NIH grant MHLBI HL35058)
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de Rooij, Alwin, Sarah van der Land e Shelly van Erp. "The Creative Proteus Effect". In C&C '17: Creativity and Cognition. New York, NY, USA: ACM, 2017. http://dx.doi.org/10.1145/3059454.3078856.
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polyphemus, Limulus, T. Muta, T. Miyata, F. Tokunaga, T. Nakamura e S. Iwanaga. "PRIMARY STRUCTURE OF ANTI-LIPOPOLYSACCHARIDE FACTOR ISOLATED FROM AMERICAN HORSESHOE CRAB". In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644608.
Testo completoAbstract (sommario):
In 1982, a protein component that inhibits the limulus coagulation cascade was found in the hemocyte lysates from Japanese and American horseshoe crabs and named anti-lipopolysaccharide (LPS) factor. This protein specifically inhibited the LPS-mediated activation of limulus factor C and had a strong anti-bacterial effect on the growth of Gram-negative R-type bacteria. Moreover, it had a hemolytic activity on the red blood cells sensitized with LPS.In the present study, the complete amino acid sequence of anti-LPS factor purified from the Limulus (L) polyphemus hemocytes was determined by characterization of the NH2-terminal sequence and the peptides generated after digestion of the protein with lysyl endopeptidase, clostripain, and Staphylococcus aureus V8 protease. Upon sequencing the peptides by the automated Edman method, the following primary structure was obtained:During the sequence analysis, two species of the protein, which differed from each other at one locus, were found and characterized. L. polyphemus anti-LPS factor was a basic protein consisting of a single polypeptide chain of 101 residues and a calculated molecular weight of 11,786 or 11,800. The hydrophobic NH2-terminal sequence and positive charges found in the disulfide loop yielded a typical amphipathic character of this protein. Moreover, L. polyphemus anti-LPS factor showed 83% sequence identity with the Tachypleus tridentatus protein (J. Aketagawa, et al. (1986) J. Biol. Chem. 261, 7357-7365), and the sequence similar to that observed in the EF-hand structure was found to contain in the COOH-terminal portions of these proteins, although its function is unknown.
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Ma, Liang, Meixiang Xu e Andres F. Oberhauser. "Nanoscale Analysis of the Effect of Pathogenic Mutations on Polycystin-1". In ASME 2010 First Global Congress on NanoEngineering for Medicine and Biology. ASMEDC, 2010. http://dx.doi.org/10.1115/nemb2010-13093.
Testo completoAbstract (sommario):
The activity of proteins and their complexes often involves the conversion of chemical energy (stored or supplied) into mechanical work through conformational changes. Mechanical forces are also crucial for the regulation of the structure and function of cells and tissues. Thus, the shape of eukaryotic cells is the result of cycles of mechano-sensing, mechano-transduction, and mechano-response. Recently developed single-molecule atomic force microscopy (AFM) techniques can be used to manipulate single molecules, both in real time and under physiological conditions, and are ideally suited to directly quantify the forces involved in both intra- and intermolecular protein interactions. In combination with molecular biology and computer simulations, these techniques have been applied to characterize the unfolding and refolding reactions in a variety of proteins, such as titin (an elastic mechano-sensing protein found in muscle) and polycystin-1 (PC1, a mechanosensor found in the kidney).
Rapporti di organizzazioni sul tema "Effet Proteus"
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Lapidot, Moshe, e Vitaly Citovsky. molecular mechanism for the Tomato yellow leaf curl virus resistance at the ty-5 locus. United States Department of Agriculture, gennaio 2016. http://dx.doi.org/10.32747/2016.7604274.bard.
Testo completoAbstract (sommario):
Tomato yellow leaf curl virus (TYLCV) is a major pathogen of tomato that causes extensive crop loss worldwide, including the US and Israel. Genetic resistance in the host plant is considered highly effective in the defense against viral infection in the field. Thus, the best way to reduce yield losses due to TYLCV is by breeding tomatoes resistant or tolerant to the virus. To date, only six major TYLCV-resistance loci, termed Ty-1 to Ty-6, have been characterized and mapped to the tomato genome. Among tomato TYLCV-resistant lines containing these loci, we have identified a major recessive quantitative trait locus (QTL) that was mapped to chromosome 4 and designated ty-5. Recently, we identified the gene responsible for the TYLCV resistance at the ty-5 locus as the tomato homolog of the gene encoding messenger RNA surveillance factor Pelota (Pelo). A single amino acid change in the protein is responsible for the resistant phenotype. Pelo is known to participate in the ribosome-recycling phase of protein biosynthesis. Our hypothesis was that the resistant allele of Pelo is a “loss-of-function” mutant, and inhibits or slows-down ribosome recycling. This will negatively affect viral (as well as host-plant) protein synthesis, which may result in slower infection progression. Hence we have proposed the following research objectives: Aim 1: The effect of Pelota on translation of TYLCV proteins: The goal of this objective is to test the effect Pelota may or may not have upon translation of TYLCV proteins following infection of a resistant host. Aim 2: Identify and characterize Pelota cellular localization and interaction with TYLCV proteins: The goal of this objective is to characterize the cellular localization of both Pelota alleles, the TYLCV-resistant and the susceptible allele, to see whether this localization changes following TYLCV infection, and to find out which TYLCV protein interacts with Pelota. Our results demonstrate that upon TYLCV-infection the resistant allele of pelota has a negative effect on viral replication and RNA transcription. It is also shown that pelota interacts with the viral C1 protein, which is the only viral protein essential for TYLCV replication. Following subcellular localization of C1 and Pelota it was found that both protein localize to the same subcellular compartments. This research is innovative and potentially transformative because the role of Peloin plant virus resistance is novel, and understanding its mechanism will lay the foundation for designing new antiviral protection strategies that target translation of viral proteins. BARD Report - Project 4953 Page 2
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Zilberstein, Aviah, Bo Liu e Einat Sadot. Studying the Involvement of the Linker Protein CWLP and its Homologue in Cytoskeleton-plasma Membrane-cell Wall Continuum and in Drought Tolerance. United States Department of Agriculture, giugno 2012. http://dx.doi.org/10.32747/2012.7593387.bard.
Testo completoAbstract (sommario):
The study has been focused on proline-rich proteins from the HyPRP family. Three proline-rich proteins have been characterized with the CWLP as the main objective. We showed that this unique protein is assembled in the plasma membrane (PM) and forms a continuum between the cell wall (CW) and cytosol via the PM. While spanning the PM, it is arranged in lipid rafts as CWLP-aquaporin complexes that recruit PP2A-β”, as a part of PP2A enzyme, close to the aquaporin moiety where it dephosphorylates two crucial Ser residues and induces closure of the aquaporin water channels. The closure of water channels renders cells more tolerant to plasmolysis and plants to dehydration. This unique effect was observed not only in Arabidopsis, but also in potato plants over expressing the CWLP, suggesting a possible usage in crop plants as a valve that reduces loss of water or/and elevates cold resistance. The CWLP is a member of the HyPRP protein family that all possess structurally similar 8CM domain, predicted to localize to PM lipid rafts. In this study, two additional highly homologous HyPRP proteins were also studied. The GPRP showed the same localization and it’s over expression increased tolerance to lack of water. However, the third one, PRP940, despite sharing high homology in the 8CM domain, is completely different and is assembled in parallel to cortical microtubules in the cell. Moreover, our data suggest that this protein is not involved in rendering plants resistant to lack of water. We suggest implying CWLP as a tool for better regulation of water maintenance in crop plants.
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Shomer, Ilan, Louise Wicker, Uzi Merin e William L. Kerr. Interactions of Cloud Proteins, Pectins and Pectinesterases in Flocculation of Citrus Cloud. United States Department of Agriculture, febbraio 2002. http://dx.doi.org/10.32747/2002.7580669.bard.
Testo completoAbstract (sommario):
The overall objective was to understand the cloud flocculation of citrus juice by characterization of the interactions between proteins and pectins, and to determine the role of PE isozymes in catalyzing this phenomenon. Specific objectives were to: 1. identify/characterize cloud-proteins in relation to their coagulable properties and affinity to pectins; 2. to determine structural changes of PME and other proteins induced by cation/pectin interactions; 3. localize cloud proteins, PME and bound protein/pectates in unheated and pasteurized juices; 4. to create "sensitized" pectins and determine their effect on clarification. The original objectives were not changed but the methods and approach were modified due to specific research requirements. Two i postulates were: 1. there is a specific interaction of cloud proteins with de-esterified regions of ! pectin and this contributes to cloud loss; 2. isozymes of pectin-methyl-esterase (PME) vary in efficiency to create sensitized pectins. The appearance of citrus fruit juice is an important quality factor and is determined by the color and turbidity that .are conferred by the suspended particles, i.e., by the cloud and its homogeneity. Under some circumstances the cloud tend to flocculate and the juice clarifies. The accepted approach to explain the clarification is based on pectin demethoxylation by PME that promotes formation of Ca-pectate. Therefore, the juice includes immediate heat-inactivation upon ~ squeezing. Protein coagulation also promotes cloud instability of citrus fruit extracts. However, the clarification mechanism is not fully understood. Information accumulated from several laboratories indicates that clarification is a more complex process than can be explained by a single mechanism. The increasing trend to consume natural-fresh juice emphasizing the importance of the knowledge to assure homogeneity of fresh juice. The research included complementary directions: Conditions that induce cloud-instability of natural- juice [IL]. Evaluate purification schemes of protein [USA]. Identifications of proteins, pectin and neutral sugars ([IL]; Structure of the cloud components using light and electron microscopy and immuno-labeling of PME, high-methoxyl-pectin (HMP) and low-methoxyl-pectin (LMP); Molecular weight of calcium sensitized pectins [US]; Evaluation of the products of PME activity [US]. Fractions and size distribution and cloud components [IL-US]. The optimal pH activity of PME is 7 and the flocculation pH of the cloud is 3-4. Thus, the c roles of PME, proteins and pectins in the cloud instability, were studied in pH ranges of 2- 7. The experiments led to establish firstly repeatable simulate conditions for cloud instability [IL]. Thermostable PME (TS-PE) known to induce cloud instability, but also thermolabile forms of PME (TL-PE) caused clarification, most likely due to the formation and dissolution of inactive :. PE-pectin complexes and displacement of a protective colloid from the cloud surface [US]. Furthermore, elimination of non-PME protein increases TS-PE activity, indicating that non-PME proteins moderate PME activity [US]. Other experiments Concomitantly with the study of the PME activity but promotes the association of cloud-proteins to pectin. Adjusting of the juice pH to f 7 retains the cloud stability and re-adjusting of the pH to 40% DE reacts to immuno-labeling in the cloud fragments, whereas
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Ohad, Itzhak, e Himadri Pakrasi. Role of Cytochrome B559 in Photoinhibition. United States Department of Agriculture, dicembre 1995. http://dx.doi.org/10.32747/1995.7613031.bard.
Testo completoAbstract (sommario):
The aim of this research project was to obtain information on the role of the cytochrome b559 in the function of Photosystem-II (PSII) with special emphasis on the light induced photo inactivation of PSII and turnover of the photochemical reaction center II protein subunit RCII-D1. The major goals of this project were: 1) Isolation and sequencing of the Chlamydomonas chloroplast psbE and psbF genes encoding the cytochrome b559 a and b subunits respectively; 2) Generation of site directed mutants and testing the effect of such mutation on the function of PSII under various light conditions; 3) To obtain further information on the mechanism of the light induced degradation and replacement of the PSII core proteins. This information shall serve as a basis for the understanding of the role of the cytochrome b559 in the process of photoinhibition and recovery of photosynthetic activity as well as during low light induced turnover of the D1 protein. Unlike in other organisms in which the psbE and psbF genes encoding the a and b subunits of cytochrome b559, are part of an operon which also includes the psbL and psbJ genes, in Chlamydomonas these genes are transcribed from different regions of the chloroplast chromosome. The charge distribution of the derived amino-acid sequences of psbE and psbF gene products differs from that of the corresponding genes in other organisms as far as the rule of "positive charge in" is concerned relative to the process of the polypeptide insertion in the thylakoid membrane. However, the sum of the charges of both subunits corresponds to the above rule possibly indicating co-insertion of both subunits in the process of cytochrome b559 assembly. A plasmid designed for the introduction of site-specific mutations into the psbF gene of C. reinhardtii. was constructed. The vector consists of a DNA fragment from the chromosome of C. reinhardtii which spans the region of the psbF gene, upstream of which the spectinomycin-resistance-conferring aadA cassette was inserted. This vector was successfully used to transform wild type C. reinhardtii cells. The spectinomycin resistant strain thus obtained can grow autotrophically and does not show significant changes as compared to the wild-type strain in PSII activity. The following mutations have been introduced in the psbF gene: H23M; H23Y; W19L and W19. The replacement of H23 involved in the heme binding to M and Y was meant to permit heme binding but eventually alter some or all of the electron transport properties of the mutated cytochrome. Tryptophane W19, a strictly conserved residue, is proximal to the heme and may interact with the tetrapyrole ring. Therefore its replacement may effect the heme properties. A change to tyrosine may have a lesser affect on the potential or electron transfer rate while a replacement of W19 by leucine is meant to introduce a more prominent disturbance in these parameters. Two of the mutants, FW19L and FH23M have segregated already and are homoplasmic. The rest are still grown under selection conditions until complete segregation will be obtained. All mutants contain assembled and functional PSII exhibiting an increased sensitivity of PSII to the light. Work is still in progress for the detailed characterization of the mutants PSII properties. A tobacco mutant, S6, obtained by Maliga and coworkers harboring the F26S mutation in the b subunit was made available to us and was characterized. Measurements of PSII charge separation and recombination, polypeptide content and electron flow indicates that this mutation indeed results in light sensitivity. Presently further work is in progress in the detailed characterization of the properties of all the above mutants. Information was obtained demonstrating that photoinactivation of PSII in vivo initiates a series of progressive changes in the properties of RCII which result in an irreversible modification of the RCII-D1 protein leading to its degradation and replacement. The cleavage process of the modified RCII-D1 protein is regulated by the occupancy of the QB site of RCII by plastoquinone. Newly synthesized D1 protein is not accumulated in a stable form unless integrated in reassembled RCII. Thus the degradation of the irreversibly modified RCII-D1 protein is essential for the recovery process. The light induced degradation of the RCII-D1 protein is rapid in mutants lacking the pD1 processing protease such as in the LF-1 mutant of the unicellular alga Scenedesmus obliquus. In this case the Mn binding site of PSII is abolished, the water oxidation process is inhibited and harmful cation radicals are formed following light induced electron flow in PSII. In such mutants photo-inactivation of PSII is rapid, it is not protected by ligands binding at the QB site and the degradation of the inactivated RCII-D1 occurs rapidly also in the dark. Furthermore the degraded D1 protein can be replaced in the dark in absence of light driven redox controlled reactions. The replacement of the RCII-D1 protein involves the de novo synthesis of the precursor protein, pD1, and its processing at the C-terminus end by an unknown processing protease. In the frame of this work, a gene previously isolated and sequenced by Dr. Pakrasi's group has been identified as encoding the RCII-pD1 C-terminus processing protease in the cyanobacterium Synechocystis sp. PCC 6803. The deduced sequence of the ctpA protein shows significant similarity to the bovine, human and insect interphotoreceptor retinoid-binding proteins. Results obtained using C. reinhardtii cells exposes to low light or series of single turnover light flashes have been also obtained indicating that the process of RCII-D1 protein turnover under non-photoinactivating conditions (low light) may be related to charge recombination in RCII due to back electron flow from the semiquinone QB- to the oxidised S2,3 states of the Mn cluster involved in the water oxidation process.
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Avni, Adi, e Gitta L. Coaker. Proteomic investigation of a tomato receptor like protein recognizing fungal pathogens. United States Department of Agriculture, gennaio 2015. http://dx.doi.org/10.32747/2015.7600030.bard.
Testo completoAbstract (sommario):
Maximizing food production with minimal negative effects on the environment remains a long-term challenge for sustainable food production. Microbial pathogens cause devastating diseases, minimizing crop losses by controlling plant diseases can contribute significantly to this goal. All plants possess an innate immune system that is activated after recognition of microbial-derived molecules. The fungal protein Eix induces defense responses in tomato and tobacco. Plants recognize Eix through a leucine-rich-repeat receptor- like-protein (LRR-RLP) termed LeEix. Despite the knowledge obtained from studies on tomato, relatively little is known about signaling initiated by RLP-type immune receptors. The focus of this grant proposal is to generate a foundational understanding of how the tomato xylanase receptor LeEix2 signals to confer defense responses. LeEix2 recognition results in pattern triggered immunity (PTI). The grant has two main aims: (1) Isolate the LeEix2 protein complex in an active and resting state; (2) Examine the biological function of the identified proteins in relation to LeEix2 signaling upon perception of the xylanase elicitor Eix. We used two separate approaches to isolate receptor interacting proteins. Transgenic tomato plants expressing LeEix2 fused to the GFP tag were used to identify complex components at a resting and activated state. LeEix2 complexes were purified by mass spectrometry and associated proteins identified by mass spectrometry. We identified novel proteins that interact with LeEix receptor by proteomics analysis. We identified two dynamin related proteins (DRPs), a coiled coil – nucleotide binding site leucine rich repeat (SlNRC4a) protein. In the second approach we used the split ubiquitin yeast two hybrid (Y2H) screen system to identified receptor-like protein kinase At5g24010-like (SlRLK-like) (Solyc01g094920.2.1) as an interactor of LeEIX2. We examined the role of SlNRC4a in plant immunity. Co-immunoprecipitation demonstrates that SlNRC4a is able to associate with different PRRs. Physiological assays with specific elicitors revealed that SlNRC4a generally alters PRR-mediated responses. SlNRC4a overexpression enhances defense responses while silencing SlNRC4 reduces plant immunity. We propose that SlNRC4a acts as a non-canonical positive regulator of immunity mediated by diverse PRRs. Thus, SlNRC4a could link both intracellular and extracellular immune perception. SlDRP2A localizes at the plasma membrane. Overexpression of SlDRP2A increases the sub-population of LeEIX2 inVHAa1 endosomes, and enhances LeEIX2- and FLS2-mediated defense. The effect of SlDRP2A on induction of plant immunity highlights the importance of endomembrane components and endocytosis in signal propagation during plant immune . The interaction of LeEIX2 with SlRLK-like was verified using co- immunoprecipitation and a bimolecular fluorescence complementation assay. The defence responses induced by EIX were markedly reduced when SlRLK-like was over-expressed, and mutation of slrlk-likeusing CRISPR/Cas9 increased EIX- induced ethylene production and SlACSgene expression in tomato. Co-expression of SlRLK-like with different RLPs and RLKs led to their degradation, apparently through an endoplasmic reticulum-associated degradation process. We provided new knowledge and expertise relevant to expression of specific be exploited to enhance immunity in crops enabling the development of novel environmentally friendly disease control strategies.
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Liao, Jianhua, Jingting Liu, Baoqing Liu, Chunyan Meng e Peiwen Yuan. Effect of OIP5-AS1 on clinicopathological characteristics and prognosis of cancer patients: a meta-analysis. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, ottobre 2022. http://dx.doi.org/10.37766/inplasy2022.10.0118.
Testo completoAbstract (sommario):
Review question / Objective: According to recent studies, long non-coding RNA (lncRNAs) i.e., OPA-interacting protein 5 antisense RNA 1 (OIP5-AS1) has an important role in various carcinomas. However, its role in the cancer is contradictory. Therefore, we aimed to evaluate the link between OIP5-AS1 and cancer patients' clinicopathological characteristics and prognosis to better understand OIP5-AS1's role in cancer. Condition being studied: Reported studies have revealed that long non-coding RNA (lncRNAs) are considerably involved in crucial physiological events in several carcinomas, it can inhibit or promote the occurrence and development of tumors by changing the sequence and spatial structure, modulating epigenetic, regulating the expression level and interacting with binding proteins. However, the mechanism of cancer regulation via lncRNAs was incompletely understood. Hence, clarifying the application value of lncRNAs in preclinical and clinical disease diagnosis and treatment was therefore the prime objective in the field of cancer research at the time.
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Pirone, Thomas P., Benjamin Raccah e Nor Chejanovsky. Vector Specificity in Potyvirus Transmission: Role of the Helper Component. United States Department of Agriculture, gennaio 2003. http://dx.doi.org/10.32747/2003.7586456.bard.
Testo completoAbstract (sommario):
Objectives: The overall objective of this research was to gain a better understanding of how potyviruses interact with their aphid vectors. The aim was to design new approaches for prevention of potyvirus spread by aphids. The sub-objectives included: (1). Determination of which of the HCs of different potyviruses effect efficient transmission by specific aphid vectors; (2). Determine regions in the HC that play a role in their compatibility with the vector; (3). Determine the factors within the aphid stylets that modify HC activity in transmission. Background of the topic: Background to the topic: Potyviruses are typical non persistent viruses. They are retained within the vector’s stylets and rapidly lost by the vector. Some potyviruses greatly differ in their ability to be transmitted by different aphid species. The present work centered on analyzing factors that may modify the interactions between the "helper component"(HC), the virions and the aphid species involved. Major conclusions, solutions and achievements: It was established that specificity of transmission may depend on aphid species used. It was also shown that specificity may depend on the affinity between HC and virion. However, the attempts to create activechimericTEV/TuMVHCs or ZYMV/TuMVHCs to identify the regions that determine interaction with a specific vector(s), were not successful. More progress was attained in objective 3: In Kentucky, tests were conducted to ascertain retention tobacco vein mottling virus (TVMV) HC in the stylets of L. erysimicompared to that in M. persicae. Ultra-thin section of stylets of aphids that fed on either TuMVHC or TVMVHC antibodies were treated with gold-labeled goat anti-rabbit antibodies.TuMV was seen in 25% the stylets of L. erysimi when they acquired TuMVHC but not when they acquired TVMVHC. In M. persicae, TVMVHC was present in 30% of the stylets. . Transmission with TuMVHC was not affected by treatment with L. erysimi saliva whereas transmission with PVYHC (which also is not functional in L. erysimi) was consistently reduced by about half. Saliva from M. persicaehad essentially no effect on either HC. The possible role aphid cuticle proteins (which are found on the stylets surface) in the association with the potyviralHC was investigated in Israel. This was done adopting two approaches: (a) isolation of cuticular proteins from aphid cuticle; (b) screening for genes encoding cuticular proteins. In the first approach, we succeeded in extracting proteins from whole homogenized M. persicaeusing concentrated urea. The extracted protein served for preparation of anti cuticular antibodies. In overlay experiments it was found that cuticular proteins specifically bind to ZYMVHC. In addition, a cDNA library of M. persicae has been prepared. Genes encoding for cuticular proteins were ascertained using antibodies to cuticular proteins. This allowed reporting the sequence of the first cuticular gene of aphids and comparing it in six aphid species. Implications, scientific and agricultural: Achievements: (1) Proofs were provided for the role of the specificity of the aphid species to the HC of certain potyviruses; (2) aphid’s saliva was found to affects transmission efficiency; (3) cuticle protein genes were isolated for the first time from aphid species and an association of cuticle protein with the potyviralHC was discerned. Agricultural and/or economic impact of the research findings: At this stage of research, our finding do not bear an agricultural or economic impact.
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Barash, Itamar, e Robert E. Rhoads. Translational Mechanisms that Govern Milk Protein Levels and Composition. United States Department of Agriculture, novembre 2004. http://dx.doi.org/10.32747/2004.7586474.bard.
Testo completoAbstract (sommario):
Original objectives: The long term objective of the project is to achieve higher content of protein in the milk of ruminants by modulating the translational machinery in the mammary gland. The first specific aim of the BARD proposal was to characterize responsiveness of various experimental systems to combination of lactogenic hormones and amino acids with particular emphasis on discrimination between the control of total protein synthesis and milk protein synthesis. Based on the results, we planned to proceed by characterizing the stage of protein synthesis in which the stimulation by lactogenic hormones and amino acid occur and finally we proposed to identify which components of the translation machinery are modified. Background to the topic: Milk protein is the most valuable component in milk, both for direct human consumption and for manufacturing cheese and other protein-based products. Attempts to augment protein content by the traditional methods of genetic selection and improved nutritional regimes have failed. The proposal was based on recent results suggesting that the limiting factor for augmenting protein synthesis in the bovine mammary gland is the efficiency of converting amino acids to milk proteins. Major conclusions, solutions, achievements: Insulin and prolactin synergistically stimulate â-casein mRNA translation by cytoplasmatic polyadenylation. The interaction between insulin and prolactin was demonstrated two decades ago as crucial for milk-protein synthesis, but the molecular mechanisms involved were not elucidated. We found in differentiated CID 9 mouse mammary epithelial cells line that insulin and prolactin synergistically increases the rate of milk protein mRNA translation. We focused on â-casein, the major milk protein, and found that the increase in â-casein mRNA translation was reflected in a shift to larger polysomes, indicating an effect on translational initiation. Inhibitors of the PI3K, mTOR, and MAPK pathways blocked insulin-stimulated total protein and â-casein synthesis but not the synergistic stimulation. Conversely, cordycepin, a polyadenylation inhibitor, abolished synergistic stimulation of protein synthesis without affecting insulin-stimulated translation. The poly(A) tract of â-casein mRNA progressively increased over 30 min of treatment with insulin plus prolactin. The 3’-untranslated region of â-casein mRNA was found to contain a cytoplasmic polyadenylation element (CPE), and in reporter constructs, this was sufficient for the translational enhancement and mRNA-specific polyadenylation. Furthermore, insulin and prolactin stimulated phosphorylation of cytoplasmic polyadenylation element binding protein (CPEB) but did not increase cytoplasmic polyadenylation.
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Chen, Junping, Zach Adam e Arie Admon. The Role of FtsH11 Protease in Chloroplast Biogenesis and Maintenance at Elevated Temperatures in Model and Crop Plants. United States Department of Agriculture, maggio 2013. http://dx.doi.org/10.32747/2013.7699845.bard.
Testo completoAbstract (sommario):
specific objectives of this proposal were to: 1) determine the location, topology, and oligomerization of FtsH11 protease; 2) identify the substrate/s of FtsH11 and the downstream components involved in maintaining thermostability of chloroplasts; 3) identify new elements involved in FtsH11 protease regulatory network related to HT adaptation processes in chloroplast; 4) Study the role of FtsH11 homologs from crop species in HT tolerance. Background to the topic: HT-tolerant varieties that maintain high photosynthetic efficiency at HT, and cope better with daily and seasonal temperature fluctuations are in great need to alleviate the effect of global warming on food production. Photosynthesis is a very complex process requiring accurate coordination of many complex systems and constant adjustments to the changing environments. Proteolytic activities mediated by various proteases in chloroplast are essential part of this process and critical for maintaining normal chloroplast functions under HT. However, little is known about mechanisms that contribute to adaptation of photosynthetic processes to HT. Our study has shown that a chloroplast-targeted Arabidopsis FtsH11 protease plays an essential and specific role in maintaining thermostability of thylakoids and normal photosynthesis at moderate HT. We hypothesized that FtsH11 homologs recently identified in other plant species might have roles similarly to that of AtFtsH1. Thus, dissecting the underlying mechanisms of FtsH11 in the adaptation mechanisms in chloroplasts to HT stress and other elements involved will aid our effort to produce more agricultural products in less favorable environments. Major conclusions, solutions, achievements - Identified the chloroplast inner envelope membrane localization of FtsH11. - Revealed a specific association of FtsH11 with the a and b subunits of CPN60. - Identified the involvement of ARC6, a protein coordinates chloroplast division machineries in plants, in FtsH11 mediated HT adaptation process in chloroplast. -Reveal possible association of a polyribonucleotide nucleotidyltransferase (cpPNPase), coded by At3G03710, with FtsH11 mediated HT adaptation process in chloroplast. - Mapped 4 additional loci in FtsH11 mediated HT adaptation network in chloroplast. - Demonstrated importance of the proteolytic activity of FtsH11 for thermotolerance, in addition to the ATPase activity. - Demonstrated a conserved role of plant FtsH11 proteases in chloroplast biogenesis and in maintaining structural and functional thermostability of chloroplast at elevated temperatures. Implications, both scientific and agricultural:Three different components interacting with FtsH11 were identified during the course of this study. At present, it is not known whether these proteins are directly involved in FtsH11mediated thermotolerance network in chloroplast and/or how these elements are interrelated. Studies aiming to connect the dot among biological functions of these networks are underway in both labs. Nevertheless, in bacteria where it was first studied, FtsH functions in heat shock response by regulating transcription level of σ32, a heat chock factor regulates HSPsexpression. FtsH also involves in control of biosynthesis of membrane components and quality control of membrane proteins etc. In plants, both Arc 6 and CPN60 identified in this study are essential in chloroplast division and developments as mutation of either one impairs chloroplast division in Arabidopsis. The facts that we have found the specific association of both α and β CPN60 with FtsH11 protein biochemically, the suppression/ enhancement of ftsh11 thermosensitive phenotype by arc6 /pnp allele genetically, implicate inter-connection of these networks via FtsH11 mediated network(s) in regulating the dynamic adaptation processes of chloroplast to temperature increases at transcriptional, translational and post-translational levels. The conserved role of FtsH11 proteases in maintaining thermostability of chloroplast at HT demonstrated here provides a foundation for improving crop photosynthetic performance at high temperatures.
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Huneeus, Cristóbal, Silvia Leiva e Alejandro Micco. Unemployment Insurance and Search Effort in Chile. Inter-American Development Bank, giugno 2012. http://dx.doi.org/10.18235/0011390.
Testo completoAbstract (sommario):
Unemployment is a pressing problem in many countries in Latin America. Financial crises and increased globalization increase job turnover and therefore the risk of unemployment. To protect workers, Chile implemented an innovative unemployment insurance (UI) system. UI protects workers but creates moral hazard and self-selection issues. Using administrative data for the period 2007 to 2010, the effect of the 2009 reform of UI on job search behavior was studied. The results revealed different job search behavior between workers who use unemployment benefits and those who do not. Search efforts were found to fall as long as unemployment benefits are in place. There is strong evidence that workers who decide not to take UI despite having the right to do so have a higher probability of finding a new job.