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Artykuły w czasopismach na temat "Stress response pathways"
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Leiser, Scott, Christopher Choi, Ajay Bhat i Charles Evans. "A Metabolic Stress Response". Innovation in Aging 4, Supplement_1 (1.12.2020): 123. http://dx.doi.org/10.1093/geroni/igaa057.404.
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Abstract An organism’s ability to respond to stress is crucial for long-term survival. These stress responses are coordinated by distinct but overlapping pathways, many of which have been found to also regulate longevity in multiple organisms across species. Despite extensive effort, our understanding of these pathways and how they affect aging remains incomplete and thus is a key area of study in Geroscience. Our previous work identified flavin-containing monooxygenase-2 (fmo-2) as a key longevity-promoting gene downstream of at least three longevity promoting pathways, including the hypoxic response, the pentose phosphate pathway, and the dietary restriction pathway. Based on the commonalities of these pathways, we hypothesized that fmo-2, a classically annotated xenobiotic enzyme, might play a key endogenous role in responding to metabolic stress. Our resulting data, using metabolic profiling and further epistatic analysis, both support this hypothesis and link fmo-2’s mechanism to modifications to one-carbon metabolism (OCM), a key intermediate pathway between the nucleotide metabolism, methylation, and transsulfuration pathways. Using mathematical modeling and a novel metabolomics approach, we were able to further identify the likely mechanism of fmo-2-mediated metabolic effects, and connect them to both OCM and downstream components. We propose a model whereby nematode fmo-2 represents a class of enzymes that are able to modify large aspects of metabolism, similar to how transcription factors modify gene expression, and that fmo-2 is a key member of a conserved metabolic stress response.
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Jennings, Paul. "Stress response pathways, toxicity pathways and adverse outcome pathways". Archives of Toxicology 87, nr 1 (13.11.2012): 13–14. http://dx.doi.org/10.1007/s00204-012-0974-4.
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Vonlaufen, Nathalie, Stefan M. Kanzok, Ronald C. Wek i William J. Sullivan Jr. "Stress response pathways in protozoan parasites". Cellular Microbiology 10, nr 12 (grudzień 2008): 2387–99. http://dx.doi.org/10.1111/j.1462-5822.2008.01210.x.
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Jayasinghe, Sisitha Udara, Sarah Janet Hall, Susan Jane Torres i Anne Isabella Turner. "Stress system dysfunction revealed by integrating reactivity of stress pathways to psychological stress in lean and overweight/obese men". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 322, nr 2 (1.02.2022): R144—R151. http://dx.doi.org/10.1152/ajpregu.00276.2021.
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Although the patterns of response within the sympathoadrenal medullary (SAM) system and hypothalamo-pituitary adrenal (HPA) axis are interesting and important in their own accord, the overall response to acute psychological stress involves reactivity of both pathways. We tested the hypothesis that consideration of the integrated response of these pathways may reveal dysregulation of the stress systems, which is not evident when considering either system alone. Age-matched lean and overweight/obese men were subjected to a Trier Social Stress Test and reactivity of the SAM system (salivary α-amylase, systolic blood pressure, diastolic blood pressure, and heart rate) and the HPA axis (salivary cortisol) were measured. Relative reactivity of SAM system and HPA axis was calculated as the ratio between the measures from each pathway. Although analysis of reactivity of individual stress pathways showed no evidence of dysfunction in overweight/obese compared with lean men, analysis of HPA/SAM reactivity revealed significantly lower cortisol over systolic blood pressure (CoSBP) and cortisol over diastolic blood pressure (CoDBP) reactivity in overweight/obese compared with lean men. Other measures of HPA/SAM reactivity and all measures of SAM/HPA reactivity were unaltered in overweight/obese compared with lean men. These findings suggest that the cortisol response per unit of blood pressure response is blunted in men with elevated adiposity. Furthermore, these findings support a notion of a coordinated overall approach to activation of the stress pathways with the degree of activation in one pathway being related to the degree of activation in the other.
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Romero, L. M., i B. M. G. Gormally. "How Truly Conserved Is the “Well-Conserved” Vertebrate Stress Response?" Integrative and Comparative Biology 59, nr 2 (22.04.2019): 273–81. http://dx.doi.org/10.1093/icb/icz011.
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Abstract The vertebrate stress response is considered to be a highly conserved suite of responses that are evolved to help animals survive noxious environmental stimuli. The two major pathways of the stress response include the catecholamine release that is part of the autonomic nervous system and comprises the immediate fight-or-flight response, and the slower release of corticosteroids from the hypothalamic–pituitary–adrenal axis that help orchestrate longer-term responses. These two pathways are present in every vertebrate yet examined, and the anatomical and physiological architecture underlying these pathways are consistent. Despite these structural similarities, however, recent data indicate substantial temporal and species variation in the actual regulation of these pathways. For example, activation of both pathways varies seasonally in some species but not others, and responses of both pathways can be extensively modulated by an individual’s previous experience. Consequently, even though the anatomy of the stress response is highly conserved, the activation and functional output is not highly conserved. Given this variation, it is perhaps not surprising that it is proving difficult to correlate individual stress responses with differences in fitness outcomes. This review summarizes the challenge of making broad generalized assumptions about fitness consequences of the stress response given the functional variation we observe.
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Araki, Eiichi, Tatsuya Kondo i Hirofumi Kai. "Cellular stress response pathways and diabetes mellitus". Diabetology International 6, nr 4 (18.08.2015): 239–42. http://dx.doi.org/10.1007/s13340-015-0229-8.
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Tew, Kenneth D. "Hematopoiesis, S-Glutathionylation and Stress Response Pathways". Free Radical Biology and Medicine 96 (lipiec 2016): S10. http://dx.doi.org/10.1016/j.freeradbiomed.2016.04.051.
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Moore, James, Ivan Osinnii, Amandine Grimm, Björn Oettinghaus, Anne Eckert, Stephan Frank i Erik C. Böttger. "Silencing of the ER and Integrative Stress Responses in the Liver of Mice with Error-Prone Translation". Cells 10, nr 11 (23.10.2021): 2856. http://dx.doi.org/10.3390/cells10112856.
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Translational errors frequently arise during protein synthesis, producing misfolded and dysfunctional proteins. Chronic stress resulting from translation errors may be particularly relevant in tissues that must synthesize and secrete large amounts of secretory proteins. Here, we studied the proteostasis networks in the liver of mice that express the Rps2-A226Y ribosomal ambiguity (ram) mutation to increase the translation error rate across all proteins. We found that Rps2-A226Y mice lack activation of the eIF2 kinase/ATF4 pathway, the main component of the integrated stress response (ISR), as well as the IRE1 and ATF6 pathways of the ER unfolded protein response (ER-UPR). Instead, we found downregulation of chronic ER stress responses, as indicated by reduced gene expression for lipogenic pathways and acute phase proteins, possibly via upregulation of Sirtuin-1. In parallel, we observed activation of alternative proteostasis responses, including the proteasome and the formation of stress granules. Together, our results point to a concerted response to error-prone translation to alleviate ER stress in favor of activating alternative proteostasis mechanisms, most likely to avoid cell damage and apoptotic pathways, which would result from persistent activation of the ER and integrated stress responses.
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Kim, Eunjung, Jae-Young Kim i Joo-Yong Lee. "Mathematical Modeling of p53 Pathways". International Journal of Molecular Sciences 20, nr 20 (18.10.2019): 5179. http://dx.doi.org/10.3390/ijms20205179.
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Cells have evolved balanced systems that ensure an appropriate response to stress. The systems elicit repair responses in temporary or moderate stress but eliminate irreparable cells via apoptosis in detrimental conditions of prolonged or severe stress. The tumor suppressor p53 is a central player in these stress response systems. When activated under DNA damage stress, p53 regulates hundreds of genes that are involved in DNA repair, cell cycle, and apoptosis. Recently, increasing studies have demonstrated additional regulatory roles of p53 in metabolism and mitochondrial physiology. Due to the inherent complexity of feedback loops between p53 and its target genes, the application of mathematical modeling has emerged as a novel approach to better understand the multifaceted functions and dynamics of p53. In this review, we discuss several mathematical modeling approaches in exploring the p53 pathways.
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Doonan, Liam B., Ashlie Hartigan, Beth Okamura i Paul F. Long. "Stress-Free Evolution: The Nrf-Coordinated Oxidative Stress Response in Early Diverging Metazoans". Integrative and Comparative Biology 59, nr 4 (23.05.2019): 799–810. http://dx.doi.org/10.1093/icb/icz055.
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Abstract Environmental stress from ultraviolet radiation, elevated temperatures or metal toxicity can lead to reactive oxygen species in cells, leading to oxidative DNA damage, premature aging, neurodegenerative diseases, and cancer. The transcription factor nuclear factor (erythroid-derived 2)-like 2 (Nrf2) activates many cytoprotective proteins within the nucleus to maintain homeostasis during oxidative stress. In vertebrates, Nrf2 levels are regulated by the Kelch-family protein Keap1 (Kelch-like ECH-associated protein 1) in the absence of stress according to a canonical redox control pathway. Little, however, is known about the redox control pathway used in early diverging metazoans. Our study examines the presence of known oxidative stress regulatory elements within non-bilaterian metazoans including free living and parasitic cnidarians, ctenophores, placozoans, and sponges. Cnidarians, with their pivotal position as the sister phylum to bilaterians, play an important role in understanding the evolutionary history of response to oxidative stress. Through comparative genomic and transcriptomic analysis our results show that Nrf homologs evolved early in metazoans, whereas Keap1 appeared later in the last common ancestor of cnidarians and bilaterians. However, key Nrf–Keap1 interacting domains are not conserved within the cnidarian lineage, suggesting this important pathway evolved with the radiation of bilaterians. Several known downstream Nrf targets are present in cnidarians suggesting that cnidarian Nrf plays an important role in oxidative stress response even in the absence of Keap1. Comparative analyses of key oxidative stress sensing and response proteins in early diverging metazoans thus provide important insights into the molecular basis of how these lineages interact with their environment and suggest a shared evolutionary history of regulatory pathways. Exploration of these pathways may prove important for the study of cancer therapeutics and broader research in oxidative stress, senescence, and the functional responses of early diverging metazoans to environmental change.
Rozprawy doktorskie na temat "Stress response pathways"
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Crowley, Cara Leilani. "Bile salt induced stress response pathways". Diss., The University of Arizona, 2000. http://hdl.handle.net/10150/289231.
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Our lab has shown that the bile salt found in the highest concentration in human fecal water, sodium deoxycholate, induces apoptosis in several cell types including Jurkat cells as well as human colonic epithelial cells. We have also found that cells within the normal appearing flat mucosa of patients with a history of colon cancer are relatively resistant to apoptosis induced by NaDOC. The current studies test the hypothesis that sodium deoxycholate induces multiple stress response pathway s that protect against apoptosis. I have tested this hypothesis by developing and analyzing cell lines that are resistant to sodium deoxycholate-induced apoptosis and focusing on two stress-response proteins known to be activated by sodium deoxycholate, poly(ADP-ribose) polymerase (PARP) and the redo-sensitive transcription factor nuclear factor-kappa B (NF-κB). I found that PARP is protective against NaDOC-induced apoptosis, and by independently inhibiting the individual subunits of NF-κB, I found that the p65 subunit is protective, while the p50 subunit is not. Development and subsequent characterization of the NaDOC-resistant HCT-116 cell lines identified several proteins that may be responsible for the development of apoptosis resistance. These proteins will be further tested in future studies.
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Bouman, Lena. "A role of parkin in stress response pathways". Diss., lmu, 2010. http://nbn-resolving.de/urn:nbn:de:bvb:19-120918.
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Mutavchiev, Delyan Rumenov. "Regulation of fission yeast cell polarity by stress-response pathways". Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/29006.
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Cell polarisation is a key biological process crucial for the functioning of essentially all cells. Regulation of cell polarity is achieved through various processes determined by both internal and external factors. An example of the latter is that cell polarity can be disrupted or lost as a consequence of a variety of external stresses. When facing such stresses, cells adapt to unfavourable conditions by activating a range of molecular signalling pathways, collectively termed ‘stress response’. Despite the connections between external stress and cell polarity, whether stress-response signalling regulates cell polarisation and what the molecular basis for such regulation remains an open question. The fission yeast Schizosaccharomyces pombe presents an excellent biological platform to study the complexity of cell polarity regulation on a systematic level. This study is aimed at understanding the functional relationship between stress-response signalling and maintenance of cell polarity in this model organism. The findings presented in this thesis set the basis for establishing a functional link between the activation of the S.pombe stress-response pathway and the activity of the master regulator of cell polarity- the Rho GTPase Cdc42. Here, I describe experiments that identify an active involvement of the stress-response mitogen-activated kinase (MAPK) Sty1 in the dispersal of active Cdc42 from the sites of growth. This new role for Sty1 occurs independently from its involvement in transcription regulation and other previously identified signalling pathways involving Sty1. Furthermore, I also find that Sty1’s involvement in Cdc42 regulation has direct implications for fission yeast physiology as it is essential for the maintenance of cellular quiescence upon nitrogen starvation. This thesis also focuses on identifying the targets of Sty1 orchestrating the active Cdc42 disruption. Here, I describe a candidate-based approach, where I investigate the role of proteins from the Cdc42 regulatory network during Sty1 activation. Additionally, I present a global phospho-proteomics approach to identify novel targets of Sty1 and offer preliminary findings which might explain Sty1’s involvement in Cdc42 regulation.
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Chalmers, Fiona. "Improving protein yield from mammalian cells by manipulation of stress response pathways". Thesis, University of Glasgow, 2016. http://theses.gla.ac.uk/7666/.
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Monoclonal antibodies are a class of therapeutic that is an expanding area of the lucrative biopharmaceutical industry. These complex proteins are predominantly produced from large cultures of mammalian cells; the industry standard cell line being Chinese Hamster Ovary (CHO) cells. A number of optimisation strategies have led to antibody titres from CHO cells increasing by a hundred-fold, and it has been proposed that a further bottleneck in biosynthesis is in protein folding and assembly within the secretory pathway. To alleviate this bottleneck, a CHO-derived host cell line was generated by researchers at the pharmaceutical company UCB that stably overexpressed two critical genes: XBP1, a transcription factor capable of expanding the endoplasmic reticulum and upregulating protein chaperones; and Ero1α, an oxidase that replenishes the machinery of disulphide bond formation. This host cell line, named CHO-S XE, was confirmed to have a high yield of secreted antibody. The work presented in this thesis further characterises CHO-S XE, with the aim of using the information gained to lead the generation of novel host cell lines with more optimal characteristics than CHO-S XE. In addition to antibodies, it was found that CHO-S XE had improved production of two other secreted proteins: one with a simple tertiary structure and one complex multi-domain protein; and higher levels of a number of endogenous protein chaperones. As a more controlled system of gene expression to unravel the specific roles of XBP1 and Ero1α in the secretory properties of CHO-S XE, CHO cells with inducible overexpression of XBP1, Ero1α, or a third gene involved in the Unfolded Protein Response, GADD34, were generated. From these cell lines, it was shown that more antibody was secreted by cells with induced overexpression of XBP1; however, Ero1α and GADD34 overexpression did not improve antibody yield. Further investigation revealed that endogenous XBP1 splicing was downregulated in the presence of an abundance of the active form of XBP1. This result indicated a novel aspect of the regulation of the activity of IRE1, the stress-induced endoribonuclease responsible for XBP1 splicing. Overall, the work described in this thesis confirms that the overexpression of XBP1 has an enhancing effect on the secretory properties of CHO cells; information which could contribute to the development of host cells with a greater capacity for antibody production.
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Richards, Siân Louise. "The involvement of Arabidopsis thaliana Annexin 1 in abiotic stress response pathways". Thesis, University of Cambridge, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648626.
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Edwards, Clare B. "The effects of supplemented metabolites on lifespan and stress response pathways in Caenorhabditis elegans". Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/5681.
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Understanding how metabolites contribute to anaplerosis, antioxidant effects, and hormetic pathways during aging is fundamental to creating supplements and dietary habits that may decrease age-associated disease and decline, thus improving the quality of life in old age. In order to uncover metabolic pathways that delay aging, the effects of large sets of metabolites associated with mitochondrial function on lifespan were investigated.
Malate, the tricarboxylic acid (TCA) cycle metabolite, increased lifespan and thermotolerance in C. elegans. Addition of fumarate and succinate also extended lifespan and all three metabolites activated nuclear translocation of the cytoprotective DAF-16/FOXO transcription factor and protected from paraquat-induced oxidative stress. The increased longevity provided by malate addition did not occur in fumarase (fum-1), glyoxylate shunt (gei-7), succinate dehydrogenase flavoprotein (sdha-2), or soluble fumarate reductaseF48E8.3 RNAi knockdown worms. Therefore, to increase lifespan, malate must be first converted to fumarate, then fumarate must be reduced to succinate by soluble fumarate reductase and the mitochondrial electron transport chain complex II. Lifespan extension induced by malate depended upon the longevity regulators DAF-16 and SIR-2.1. Malate supplementation did not extend the lifespan of long-lived eat-2 mutant worms, a model of dietary restriction. Malate and fumarate addition increased oxygen consumption, but decreased ATP levels and mitochondrial membrane potential suggesting a mild uncoupling of oxidative phosphorylation.
Each of the twenty amino acids was individually supplemented to C. elegans and the effects on lifespan were determined. All amino acids except phenylalanine were found to extend lifespan at least to a small extent at one or more of the 3 concentrations tested with serine, histidine, and proline showing the largest effects. In most cases, amino acid supplementation did not extend lifespan in eat-2 worms, a model of dietary restriction or in daf-16, sir-2.1, rsks-1 (S6 kinase), or aak-2 (AMPK) longevity pathway mutants or in worms fed RNAi to skn-1, the C. elegans Nrf2 homolog. Serine and tryptophan addition further protected worms from Alzheimer’s amyloid-beta toxicity. Tryptophan and its catabolites nicotinic acid, picolinic acid, and NAD further induced a broad heat shock response. These results indicate that dietary amino acid imbalance and amino acid catabolism affect organismal longevity.
The ketone body beta-hydroxybutyrate (βHB) is a histone deacetylase (HDAC) inhibitor and has been shown to be protective in many disease models, but its effects on aging are not well studied. Therefore we determined the effect of βHB supplementation on the lifespan of C. elegans. βHB supplementation extended mean lifespan by approximately 20%. RNAi knockdown of HDACs hda-2 or hda-3 also increased lifespan and further prevented βHB-mediated lifespan extension. βHB-mediated lifespan extension required the DAF-16/FOXO and SKN-1/Nrf longevity pathways, the sirtuin SIR-2.1, and the AMP kinase subunit AAK-2. βHB did not extend lifespan in a genetic model of dietary restriction indicating that βHB is likely functioning through a similar mechanism. βHB addition also upregulated ΒHB dehydrogenase activity and increased oxygen consumption in the worms. RNAi knockdown of F55E10.6, a short chain dehydrogenase and SKN-1 target gene, prevented the increased lifespan and βHB dehydrogenase activity induced by βHB addition, suggesting that F55E10.6 functions as an inducible βHB dehydrogenase. Furthermore, βHB supplementation delayed Alzheimer's amyloid-beta toxicity and decreased Parkinson's alpha-synuclein aggregation. The results indicate that D-βHB extends lifespan through inhibiting HDACs and through the activation of conserved stress response pathways.
Aging is a progressive disease caused by the time dependent decline of an organism and is the primary risk factor for many human ailments, including heart disease, cancer, and Alzheimer’s disease. Uncovering metabolic pathways and metabolites that delay the onset of age-related decline was the primary drive of this investigation.
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Ryan, Ellis Louise. "Investigating the role of TAB182 in the DNA damage response and replication stress pathways". Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/6741/.
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It is well established that adenoviruses degrade components of the cellular DNA damage response, such as p53, DNA ligase IV and Mre11, in order to avoid detection from the host cell and thus, promote viral replication. Here we show TAB182, a protein of previously unknown function, is degraded following adenovirus serotype 5 and 12 infection. Similarly to other DNA damage proteins, together with the cellular Cullin 5 (during Ad5 infection) and Cullin 2 (during Ad12 infection). Interestingly, siRNA-mediated knockdown of TAB182 appears to be beneficial for adenovirus infection, as denoted by an increased expression of the adenoviral E1A protein and Cyclin E during adenovirus infection. Together with other studies, we confirm that TAB182 interacts with the large, multi-subunit CNOT complex. This complex has no defined function in mammalian cells, but is known to play a role in gene regulation in yeast. Interestingly, components of the CNOT complex are also degraded during adenovirus infection, whether adenovirus degrades TAB182 as well as CNOT for the same advantage is currently unknown. Cells deficient in TAB182 are hypersensitive to agents that induce DNA replication stress and also exhibit abnormal replication dynamics following release from hydroxyurea-induced fork stalling. In particular, they display increased fork restart and elevated new origin firing following release from hydroxyurea treatment, suggesting that TAB182 prevents fork recovery and suppresses new origin firing following replication stress. Depletion of some components of the CNOT complex is able to rescue the phenotypes observed in TAB182 deficient cells, suggesting that TAB182 and the CNOT complex may act in concert at the replication fork. TAB182 deficient cells display less DNA gaps and breaks but increased levels of 53BP1 bodies in G1 and micronuclei, which are markers of genome instability, following replication stress. Whether TAB182 acts directly at the replication fork, or in conjunction with other proteins known to be involved in replication restart such as helicases, nucleases, or chromatin remodelling complexes, remains to be elucidated.
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Weatherbee, Jessica L. "Exploiting DNA Repair and ER Stress Response Pathways to Induce Apoptosis in Glioblastoma Multiforme: A Dissertation". eScholarship@UMMS, 2016. https://escholarship.umassmed.edu/gsbs_diss/865.
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Glioblastoma multiforme (GBM) is a deadly grade IV brain tumor characterized by a heterogeneous population of cells that are drug resistant, aggressive, and infiltrative. The current standard of care, which has not changed in over a decade, only provides GBM patients with 12-14 months survival post diagnosis. We asked if the addition of a novel endoplasmic reticulum (ER) stress inducing agent, JLK1486, to the standard chemotherapy, temozolomide (TMZ), which induces DNA double strand breaks (DSBs), would enhance TMZ’s efficacy. Because GBMs rely on the ER to mitigate their hypoxic environment and DNA repair to fix TMZ induced DSBs, we reasoned that DSBs occurring during heightened ER stress would be deleterious.
Treatment of GBM cells with TMZ+JLK1486 decreased cell viability and increased cell death due to apoptosis. We found that TMZ+JLK1486 prolonged ER stress induction, as indicated by elevated ER stress marker BiP, ATF4, and CHOP, while sustaining activation of the DNA damage response pathway. This combination produced unresolved DNA DSBs due to RAD51 reduction, a key DNA repair factor. The combination of TMZ+JLK1486 is a potential novel therapeutic combination and suggests an inverse relationship between ER stress and DNA repair pathways.
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Melgar, Katelyn M. "A polypharmacologic strategy for overcoming adaptive therapy resistance in AML by targeting immune stress response pathways". University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1571061798761171.
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Weatherbee, Jessica L. "Exploiting DNA Repair and ER Stress Response Pathways to Induce Apoptosis in Glioblastoma Multiforme: A Dissertation". eScholarship@UMMS, 2008. http://escholarship.umassmed.edu/gsbs_diss/865.
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Glioblastoma multiforme (GBM) is a deadly grade IV brain tumor characterized by a heterogeneous population of cells that are drug resistant, aggressive, and infiltrative. The current standard of care, which has not changed in over a decade, only provides GBM patients with 12-14 months survival post diagnosis. We asked if the addition of a novel endoplasmic reticulum (ER) stress inducing agent, JLK1486, to the standard chemotherapy, temozolomide (TMZ), which induces DNA double strand breaks (DSBs), would enhance TMZ’s efficacy. Because GBMs rely on the ER to mitigate their hypoxic environment and DNA repair to fix TMZ induced DSBs, we reasoned that DSBs occurring during heightened ER stress would be deleterious.
Treatment of GBM cells with TMZ+JLK1486 decreased cell viability and increased cell death due to apoptosis. We found that TMZ+JLK1486 prolonged ER stress induction, as indicated by elevated ER stress marker BiP, ATF4, and CHOP, while sustaining activation of the DNA damage response pathway. This combination produced unresolved DNA DSBs due to RAD51 reduction, a key DNA repair factor. The combination of TMZ+JLK1486 is a potential novel therapeutic combination and suggests an inverse relationship between ER stress and DNA repair pathways.
Książki na temat "Stress response pathways"
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Wondrak, Georg T., red. Skin Stress Response Pathways. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-43157-4.
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Wondrak, Georg T., red. Stress Response Pathways in Cancer. Dordrecht: Springer Netherlands, 2015. http://dx.doi.org/10.1007/978-94-017-9421-3.
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Herman, James P. Limbic Pathways to Stress Control. Redaktorzy Israel Liberzon i Kerry J. Ressler. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780190215422.003.0008.
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Appropriate control of the HPA (hypothalamo-pituitary-adrenocortical axis) is required for adaptation to physiological and environmental challenges. Inadequate control is linked to numerous stress-related pathologies, including PTSD, highlighting its importance in linking physiological stress responses with behavioral coping strategies. This chapter highlights neurocircuit mechanisms underlying HPA axis adaptation and pathology. Control of the HPA stress response is mediated by the coordinated activity of numerous limbic brain regions, including the prefrontal cortex, hippocampus, and amygdala. In general, hippocampal output inhibits anticipatory HPA axis responses, whereas amygdala subnuclei participate in stress activation. The prefrontal cortex plays an important role in inhibition of context-dependent stress responses. These regions converge on subcortical structures that relay information to paraventricular nucleus corticotropin-releasing hormone neurons, controlling the magnitude and duration of HPA axis stress responses. The output of these neural networks determines the net effect on glucocorticoid secretion, both within the normal adaptive range and in pathological circumstances.
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Wondrak, Georg T. Skin Stress Response Pathways: Environmental Factors and Molecular Opportunities. Springer, 2018.
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Wondrak, Georg T. Skin Stress Response Pathways: Environmental Factors and Molecular Opportunities. Springer, 2016.
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Wondrak, Georg T. Skin Stress Response Pathways: Environmental Factors and Molecular Opportunities. Springer London, Limited, 2016.
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Wondrak, Georg T. Stress Response Pathways in Cancer: From Molecular Targets to Novel Therapeutics. Springer, 2016.
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Wondrak, Georg T. Stress Response Pathways in Cancer: From Molecular Targets to Novel Therapeutics. Springer, 2014.
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Wondrak, Georg T. Stress Response Pathways in Cancer: From Molecular Targets to Novel Therapeutics. Springer, 2014.
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Huang, Ruili, i Menghang Xia, red. Tox21 Challenge to Build Predictive Models of Nuclear Receptor and Stress Response Pathways as Mediated by Exposure to Environmental Toxicants and Drugs. Frontiers Media SA, 2017. http://dx.doi.org/10.3389/978-2-88945-197-5.
Pełny tekst źródłaCzęści książek na temat "Stress response pathways"
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Miller, Dana L., Joseph Horsman i Frazer I. Heinis. "Stress Response Pathways". W Healthy Ageing and Longevity, 191–217. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-44703-2_9.
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Leonard, Martin O., Alice Limonciel i Paul Jennings. "Stress Response Pathways". W Methods in Pharmacology and Toxicology, 433–58. New York, NY: Springer New York, 2014. http://dx.doi.org/10.1007/978-1-4939-0521-8_19.
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Gruber, Florian. "The Skin Lipidome Under Environmental Stress—Technological Platforms, Molecular Pathways and Translational Opportunities". W Skin Stress Response Pathways, 1–27. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-43157-4_1.
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Byrne, Scott N., i Gary M. Halliday. "UV-Induced Chemokines as Emerging Targets for Skin Cancer Photochemoprevention". W Skin Stress Response Pathways, 211–34. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-43157-4_10.
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Tamagawa-Mineoka, Risa, Mayumi Ueta i Norito Katoh. "TLR3 and Inflammatory Skin Diseases: From Environmental Factors to Molecular Opportunities". W Skin Stress Response Pathways, 235–49. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-43157-4_11.
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He, Yu-Ying. "Sirtuins and Stress Response in Skin Cancer, Aging, and Barrier Function". W Skin Stress Response Pathways, 251–63. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-43157-4_12.
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Chajra, Hanane. "Cutaneous Opioid Receptors and Stress Responses: Molecular Interactions and Opportunities for Therapeutic Intervention". W Skin Stress Response Pathways, 265–80. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-43157-4_13.
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van Spyk, Elyse, Milton Greenberg, Faraj Mourad i Bogi Andersen. "Regulation of Cutaneous Stress Response Pathways by the Circadian Clock: From Molecular Pathways to Therapeutic Opportunities". W Skin Stress Response Pathways, 281–300. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-43157-4_14.
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Oddi, Sergio, i Mauro Maccarrone. "Endocannabinoids and Skin Barrier Function: Molecular Pathways and Therapeutic Opportunities". W Skin Stress Response Pathways, 301–23. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-43157-4_15.
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Justiniano, Rebecca, i Georg T. Wondrak. "The Aryl Hydrocarbon Receptor (AhR) as an Environmental Stress Sensor and Regulator of Skin Barrier Function: Molecular Mechanisms and Therapeutic Opportunities". W Skin Stress Response Pathways, 325–59. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-43157-4_16.
Pełny tekst źródłaStreszczenia konferencji na temat "Stress response pathways"
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Sridharan, Sriram, Ritwik Layek, Aniruddha Datta i Jijayanagaram Venkatraj. "Modelling oxidative stress response pathways". W 2011 IEEE International Workshop on Genomic Signal Processing and Statistics (GENSIPS). IEEE, 2011. http://dx.doi.org/10.1109/gensips.2011.6169471.
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Varghese, Rajani, Sriram Sridharan, Aniruddha Datta i Jijayanagaram Venkatraj. "Modeling hypoxia stress response pathways". W 2013 IEEE International Workshop on Genomic Signal Processing and Statistics (GENSIPS). IEEE, 2013. http://dx.doi.org/10.1109/gensips.2013.6735939.
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Sridharan, S., R. Layek, A. Datta i J. Venkatraj. "Boolean network model of oxidative stress response pathways". W 2012 American Control Conference - ACC 2012. IEEE, 2012. http://dx.doi.org/10.1109/acc.2012.6315168.
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Hu, Fu-Yan, Xing-Ming Zhao, Luonan Chen, Kun He, Le Lu, Yongwei Cao i Jingdong Liu. "Identifying rice arsenic stress response pathways based on molecular interaction network". W 2012 IEEE 4th International Symposium on Plant Growth Modeling, Simulation, Visualization and Applications (PMA). IEEE, 2012. http://dx.doi.org/10.1109/pma.2012.6524828.
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Li, G., S. S. Nair, S. J. Lees i F. W. Booth. "Regulation of G2/M Transition in Mammalian Cells by Oxidative Stress". W ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-82349.
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The regulation of the G2/M transition for the mammalian cell cycle has been modeled using 19 states to investigate the G2 checkpoint dynamics in response to oxidative stress. A detailed network model of G2/M regulation is presented and then a “core” subsystem is extracted from the full network. An existing model of Mitosis control is extended by adding two important pathways regulating G2/M transition in response to DNA damage induced by oxidative stress. Model predictions indicate that the p53 dependent pathway is not required for initial G2 arrest as the Chk1/Cdc25C pathway can arrest the cell in G2 right after DNA damage. However, p53 and p21 expression is important for a more sustained G2 arrest by inhibiting the Thr161 phosphorylation by CAK. By eliminating the phosphorylation effect of Chk1 on p53, two completely independent pathways are obtained and it is shown that it does not affect the G2 arrest much. So the p53/p21 pathway makes an important, independent contribution to G2 arrest in response to oxidative stress, and any defect in this pathway may lead to genomic instability and predisposition to cancer. Such strict control mechanisms probably provide protection for survival in the face of various environmental changes. The controversial issue related to the mechanism of inactivation of Cdc2 by p21 is addressed and simulation predictions indicate that G2 arrest would not be affected much by considering the direct binding of p21 to Cdc2/Cyclin B given that the inhibition of CAK by p21 is already present if the binding efficiency is within a certain range. Lastly, we show that the G2 arrest time in response to oxidative stress is sensitive to the p53 synthesis rate.
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Ahmed, Amira, Huda Farah, Omnia Ahmed, Dina Elsayegh, Abdelrahman Elgamal i Nasser Moustafa Rizk. "Profile Of Oxidative Stress Genes In Response To Obesity Treatment". W Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2021. http://dx.doi.org/10.29117/quarfe.2021.0150.
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Background: Oxidative stress (OS) is an imbalance between free radical production and the antioxidants defense in the body. Previous studies demonstrated the correlation of OS to the increased risk of developing metabolic disorders such as obesity. Sulforaphane (SFN), a bioactive compound, can protect against inflammation and OS, thus an effective anti-obesity supplement. Aim: This study explores the impact of SNF on OS in diet induced obese (DIO) mice via profiling of OS genes and pathways in skeletal muscles related to the anti-obesity effect. Methods: Wild-type CD1 male mice and the knockout of nuclear factor (erythroid-derived 2) like 2 (NrF2) mice were fed a high-fat diet (HFD) for 16 weeks; to induce obesity. Subsequently, each group was subdivided into two subgroups and received either Vehicle (25μl) or SFN (5 mg/kg BW) for four weeks. Body weight was measured daily, and a glucose tolerance test (GTT) was performed after 21 days of treatment. Afterward, mice were decapitated, blood and tissue samples were collected and snap-frozen immediately. Total RNA was extracted from Skeletal muscle and epididymal white adipose tissue (eWAT), leptin expression was measured in (eWAT), and 84 OS genes in skeletal muscle were examined using RT-PCR. Results: Significant reduction in body weight in SFN treated WT mice, while no change in KO mice. Plasma glucose, leptin, and leptin gene expression (eWAT) were significantly reduced in the WT-DIO SFN treated group, while no changes were detected in KO mice. SFN decreases OS damage in skeletal muscles, such as lipid peroxidation and production of reactive oxygen species (ROS). Conclusion: This study demonstrated that SFN had lowered body weight in WT-DIO mice by decreasing OS damage in skeletal muscles through the NrF2 pathway and can be a potential anti-obesity drug.
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Park, Jihyun, Qiantao Wang, Tamer S. Kaoud, Clint D. J. Tavares, Ramakrishna Edupuganti, Pengyu Ren i Kevin N. Dalby. "Abstract 513: Investigating stress-response pathways in pancreatic cancer cells using novel PERK inhibitors". W Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA. American Association for Cancer Research, 2014. http://dx.doi.org/10.1158/1538-7445.am2014-513.
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Tameire, Feven Tameire, i Costas Koumenis. "Abstract A34: The stress response transcription factor ATF4 mediates cytoprotective pathways in c-Myc overexpressing cells". W Abstracts: AACR Special Conference on Myc: From Biology to Therapy; January 7-10, 2015; La Jolla, CA. American Association for Cancer Research, 2015. http://dx.doi.org/10.1158/1557-3125.myc15-a34.
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Cao, Anthony, Ryan Heiser, Che-Leung Law i Shyra J. Gardai. "Abstract 4914: Auristatin-based antibody drug conjugates activate multiple ER stress response pathways resulting in immunogenic cell death and amplified T-cell responses". W Proceedings: AACR 107th Annual Meeting 2016; April 16-20, 2016; New Orleans, LA. American Association for Cancer Research, 2016. http://dx.doi.org/10.1158/1538-7445.am2016-4914.
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Zhou, B., M. Horie, P. Flodby, H. Wang, Y. Liu, A. Lee i Z. Borok. "Transcriptomic Analysis Identifies Pathways Mediating Alveolar Epithelial Type II (AT2) Cell Dysfunction and Fibrosis in Response to ER Stress Following Grp78 Knockout (KO)". W American Thoracic Society 2019 International Conference, May 17-22, 2019 - Dallas, TX. American Thoracic Society, 2019. http://dx.doi.org/10.1164/ajrccm-conference.2019.199.1_meetingabstracts.a7233.
Pełny tekst źródłaRaporty organizacyjne na temat "Stress response pathways"
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Zhou, Jizhong, i Zhili He. Deduction and Analysis of the Interacting Stress Response Pathways of Metal/Radionuclide-reducing Bacteria. Office of Scientific and Technical Information (OSTI), luty 2010. http://dx.doi.org/10.2172/1098145.
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Horwitz, Benjamin A., i Barbara Gillian Turgeon. Fungal Iron Acquisition, Oxidative Stress and Virulence in the Cochliobolus-maize Interaction. United States Department of Agriculture, marzec 2012. http://dx.doi.org/10.32747/2012.7709885.bard.
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Our project focused on genes for high affinity iron acquisition in Cochliobolus heterostrophus, a necrotrophic pathogen of maize, and their intertwined relationship to oxidative stress status and virulence of the fungus on the host. An intriguing question was why mutants lacking the nonribosomal peptide synthetase (NRPS) gene (NPS6) responsible for synthesis of the extracellular siderophore, coprogen, are sensitive to oxidative stress. Our overall objective was to understand the mechanistic connection between iron stress and oxidative stress as related to virulence of a plant pathogen to its host. The first objective was to examine the interface where small molecule peptide and reactive oxygen species (ROS) mechanisms overlap. The second objective was to determine if the molecular explanation for common function is common signal transduction pathways. These pathways, built around sensor kinases, response regulators, and transcription factors may link sequestering of iron, production of antioxidants, resistance to oxidative stress, and virulence. We tested these hypotheses by genetic manipulation of the pathogen, virulence assays on the host plant, and by following the expression of key fungal genes. An addition to the original program, made in the first year, was to develop, for fungi, a genetically encoded indicator of redox state based on the commercially available Gfp-based probe pHyper, designed for animal cell biology. We implemented several tools including a genetically encoded indicator of redox state, a procedure to grow iron-depleted plants, and constructed a number of new mutants in regulatory genes. Lack of the major Fe acquisition pathways results in an almost completely avirulent phenotype, showing how critical Fe acquisition is for the pathogen to cause disease. Mutants in conserved signaling pathways have normal ability to regulate NPS6 in response to Fe levels, as do mutants in Lae1 and Vel1, two master regulators of gene expression. Vel1 mutants are sensitive to oxidative stress, and the reason may be underexpression of a catalase gene. In nps6 mutants, CAT3 is also underexpressed, perhaps explaining the sensitivity to oxidative stress. We constructed a deletion mutant for the Fe sensor-regulator SreA and found that it is required for down regulation of NPS6 under Fe-replete conditions. Lack of SreA, though, did not make the fungus over-sensitive to ROS, though the mutant had a slow growth rate. This suggests that overproduction of siderophore under Fe-replete conditions is not very damaging. On the other hand, increasing Fe levels protected nps6 mutants from inhibition by ROS, implying that Fe-catalyzed Fenton reactions are not the main factor in its sensitivity to ROS. We have made some progress in understanding why siderophore mutants are sensitive to oxidative stress, and in doing so, defined some novel regulatory relationships. Catalase genes, which are not directly related to siderophore biosynthesis, are underexpressed in nps6 mutants, suggesting that the siderophore product (with or without bound Fe) may act as a signal. Siderophores, therefore, could be a target for intervention in the field, either by supplying an incorrect signal or blocking a signal normally provided during infection. We already know that nps6 mutants cause smaller lesions and have difficulty establishing invasive growth in the host. Lae1 and Vel1 are the first factors shown to regulate both super virulence conferred by T-toxin, and basic pathogenicity, due to unknown factors. The mutants are also altered in oxidative stress responses, key to success in the infection court, asexual and sexual development, essential for fungal dissemination in the field, aerial hyphal growth, and pigment biosynthesis, essential for survival in the field. Mutants in genes encoding NADPH oxidase (Nox) are compromised in development and virulence. Indeed the triple mutant, which should lack all Nox activity, was nearly avirulent. Again, gene expression experiments provided us with initial evidence that superoxide produced by the fungus may be most important as a signal. Blocking oxidant production by the pathogen may be a way to protect the plant host, in interactions with necrotrophs such as C. heterostrophus which seem to thrive in an oxidant environment.
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Miller, Gad, i Jeffrey F. Harper. Pollen fertility and the role of ROS and Ca signaling in heat stress tolerance. United States Department of Agriculture, styczeń 2013. http://dx.doi.org/10.32747/2013.7598150.bard.
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The long-term goal of this research is to understand how pollen cope with stress, and identify genes that can be manipulated in crop plants to improve reproductive success during heat stress. The specific aims were to: 1) Compare heat stress dependent changes in gene expression between wild type pollen, and mutants in which pollen are heat sensitive (cngc16) or heat tolerant (apx2-1). 2) Compare cngc16 and apx2 mutants for differences in heat-stress triggered changes in ROS, cNMP, and Ca²⁺ transients. 3) Expand a mutant screen for pollen with increased or decreased thermo-tolerance. These aims were designed to provide novel and fundamental advances to our understanding of stress tolerance in pollen reproductive development, and enable research aimed at improving crop plants to be more productive under conditions of heat stress. Background: Each year crop yields are severely impacted by a variety of stress conditions, including heat, cold, drought, hypoxia, and salt. Reproductive development in flowering plants is highly sensitive to hot or cold temperatures, with even a single hot day or cold night sometimes being fatal to reproductive success. In many plants, pollen tube development and fertilization is often the weakest link. Current speculation about global climate change is that most agricultural regions will experience more extreme environmental fluctuations. With the human food supply largely dependent on seeds, it is critical that we consider ways to improve stress tolerance during fertilization. The heat stress response (HSR) has been intensively studied in vegetative tissues, but is poorly understood during reproductive development. A general paradigm is that HS is accompanied by increased production of reactive oxygen species (ROS) and induction of ROS-scavenging enzymes to protect cells from excess oxidative damage. The activation of the HSR has been linked to cytosolic Ca²⁺ signals, and transcriptional and translational responses, including the increased expression of heat shock proteins (HSPs) and antioxidative pathways. The focus of the proposed research was on two mutations, which have been discovered in a collaboration between the Harper and Miller labs, that either increase or decrease reproductive stress tolerance in a model plant, Arabidopsis thaliana (i.e., cngc16--cyclic nucleotide gated channel 16, apx2-1--ascorbate peroxidase 2,). Major conclusions, solutions, achievements. Using RNA-seq technology, the expression profiles of cngc16 and apx2 pollen grains were independently compared to wild type under favourable conditions and following HS. In comparison to a wild type HSR, there were 2,776 differences in the transcriptome response in cngc16 pollen, consistent with a model in which this heat-sensitive mutant fails to enact or maintain a normal wild-type HSR. In a comparison with apx2 pollen, there were 900 differences in the HSR. Some portion of these 900 differences might contribute to an improved HSR in apx2 pollen. Twenty-seven and 42 transcription factor changes, in cngc16 and apx2-1, respectively, were identified that could provide unique contributions to a pollen HSR. While we found that the functional HS-dependent reprogramming of the pollen transcriptome requires specific activity of CNGC16, we identified in apx2 specific activation of flavonol-biosynthesis pathway and auxin signalling that support a role in pollen thermotolerance. Results from this study have identified metabolic pathways and candidate genes of potential use in improving HS tolerance in pollen. Additionally, we developed new FACS-based methodology that can quantify the stress response for individual pollen in a high-throughput fashion. This technology is being adapted for biological screening of crop plant’s pollen to identify novel thermotolerance traits. Implications, both scientific and agricultural. This study has provided a reference data on the pollen HSR from a model plant, and supports a model that the HSR in pollen has many differences compared to vegetative cells. This provides an important foundation for understanding and improving the pollen HSR, and therefor contributes to the long-term goal of improving productivity in crop plants subjected to temperature stress conditions. A specific hypothesis that has emerged from this study is that pollen thermotolerance can be improved by increasing flavonol accumulation before or during a stress response. Efforts to test this hypothesis have been initiated, and if successful have the potential for application with major seed crops such as maize and rice.
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Sela, Shlomo, i Michael McClelland. Investigation of a new mechanism of desiccation-stress tolerance in Salmonella. United States Department of Agriculture, styczeń 2013. http://dx.doi.org/10.32747/2013.7598155.bard.
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Low-moisture foods (LMF) are increasingly involved in foodborne illness. While bacteria cannot grow in LMF due to the low water content, pathogens such as Salmonella can still survive in dry foods and pose health risks to consumer. We recently found that Salmonella secretes a proteinaceous compound during desiccation, which we identified as OsmY, an osmotic stress response protein of 177 amino acids. To elucidate the role of OsmY in conferring tolerance against desiccation and other stresses in Salmonella entericaserovarTyphimurium (STm), our specific objectives were: (1) Characterize the involvement of OsmY in desiccation tolerance; (2) Perform structure-function analysis of OsmY; (3) Study OsmY expression under various growth- and environmental conditions of relevance to agriculture; (4) Examine the involvement of OsmY in response to other stresses of relevance to agriculture; and (5) Elucidate regulatory pathways involved in controlling osmY expression. We demonstrated that an osmY-mutant strain is impaired in both desiccation tolerance (DT) and in long-term persistence during cold storage (LTP). Genetic complementation and addition of a recombinantOsmY (rOsmY) restored the mutant survival back to that of the wild type (wt). To analyze the function of specific domains we have generated a recombinantOsmY (rOsmY) protein. A dose-response DT study showed that rOsmY has the highest protection at a concentration of 0.5 nM. This effect was protein- specific as a comparable amount of bovine serum albumin, an unrelated protein, had a three-time lower protection level. Further characterization of OsmY revealed that the protein has a surfactant activity and is involved in swarming motility. OsmY was shown to facilitate biofilm formation during dehydration but not during bacterial growth under optimal growth conditions. This finding suggests that expression and secretion of OsmY under stress conditions was potentially associated with facilitating biofilm production. OsmY contains two conserved BON domains. To better understand the role of the BON sites in OsmY-mediated dehydration tolerance, we have generated two additional rOsmY constructs, lacking either BON1 or BON2 sites. BON1-minus (but not BON2) protein has decreased dehydration tolerance compared to intact rOsmY, suggesting that BON1 is required for maximal OsmY-mediated activity. Addition of BON1-peptide at concentration below 0.4 µM did not affect STm survival. Interestingly, a toxic effect of BON1 peptide was observed in concentration as low as 0.4 µM. Higher concentrations resulted in complete abrogation of the rOsmY effect, supporting the notion that BON-mediated interaction is essential for rOsmY activity. We performed extensive analysis of RNA expression of STm undergoing desiccation after exponential and stationary growth, identifying all categories of genes that are differentially expressed during this process. We also performed massively in-parallel screening of all genes in which mutation caused changes in fitness during drying, identifying over 400 such genes, which are now undergoing confirmation. As expected OsmY is one of these genes. In conclusion, this is the first study to identify that OsmY protein secreted during dehydration contributes to desiccation tolerance in Salmonella by facilitating dehydration- mediated biofilm formation. Expression of OsmY also enhances swarming motility, apparently through its surfactant activity. The BON1 domain is required for full OsmY activity, demonstrating a potential intervention to reduce pathogen survival in food processing. Expression and fitness screens have begun to elucidate the processes of desiccation, with the potential to uncover additional specific targets for efforts to mitigate pathogen survival in desiccation.
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Chejanovsky, Nor, Diana Cox-Foster, Victoria Soroker i Ron Ophir. Honeybee modulation of infection with the Israeli acute paralysis virus, in asymptomatic, acutely infected and CCD colonies. United States Department of Agriculture, grudzień 2013. http://dx.doi.org/10.32747/2013.7594392.bard.
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Honey bee (Apis mellifera) colony losses pose a severe risk to the food chain. The IAPV (Israeli acute paralysis virus) was correlated with CCD, a particular case of colony collapse. Honey bees severely infected with IAPV show shivering wings that progress to paralysis and subsequent death. Bee viruses, including IAPV, are widely present in honey bee colonies but often there are no pathological symptoms. Infestation of the beehive with Varroa mites or exposure to stress factors leads to significant increase in viral titers and fatal infections. We hypothesized that the honey bee is regulating/controlling IAPV and viral infections in asymptomatic infections and this control is broken through "stress" leading to acute infections and/or CCD. Our aims were: 1. To discover genetic changes in IAPV that may affect tissue tropism in the host, and/or virus infectivity and pathogenicity. 2. To elucidate mechanisms used by the host to regulate/ manage the IAPV-infection in vivo and in vitro. To achieve the above objectives we first studied stress-induced virus activation. Our data indicated that some pesticides, including myclobutanil, chlorothalonil and fluvalinate, result in amplified viral titers when bees are exposed at sub lethal levels by a single feeding. Analysis of the level of immune-related bee genes indicated that CCD-colonies exhibit altered and weaker immune responses than healthy colonies. Given the important role of viral RNA interference (RNAi) in combating viral infections we investigated if CCD-colonies were able to elicit this particular antiviral response. Deep-sequencing analysis of samples from CCD-colonies from US and Israel revealed high frequency of small interfering RNAs (siRNA) perfectly matching IAPV, Kashmir bee virus and Deformed wing virus genomes. Israeli colonies showed high titers of IAPV and a conserved RNAi pattern of targeting the viral genome .Our findings were further supported by analysis of samples from colonies experimentally infected with IAPV. Following for the first time the dynamics of IAPV infection in a group of CCD colonies that we rescued from collapse, we found that IAPV conserves its potential to act as one lethal, infectious factor and that its continuous replication in CCD colonies deeply affects their health and survival. Ours is the first report on the dominant role of IAPV in CCD-colonies outside from the US under natural conditions. We concluded that CCD-colonies do exhibit a regular siRNA response that is specific against predominant viruses associated with colony losses and other immune pathways may account for their weak immune response towards virus infection. Our findings: 1. Reveal that preventive measures should be taken by the beekeepers to avoid insecticide-based stress induction of viral infections as well as to manage CCD colonies as a source of highly infectious viruses such as IAPV. 2. Contribute to identify honey bee mechanisms involved in managing viral infections.
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Ginzberg, Idit, i Walter De Jong. Molecular genetic and anatomical characterization of potato tuber skin appearance. United States Department of Agriculture, wrzesień 2008. http://dx.doi.org/10.32747/2008.7587733.bard.
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Potato (Solanum tuberosum L.) skin is composed of suberized phellem cells, the outer component of the tuber periderm. The focus of the proposed research was to apply genomic approaches to identify genes that control tuber skin appearance - smooth and shiny skin is highly preferred by the customers while russeted/netted skin potatoes are rejected. The breeding program (at Cornell University) seeks to develop smooth-skin varieties but has encountered frequent difficulties as inheritance of russeting involves complementary action by independently segregating genes, where a dominant allele at each locus is required for any degree of skin russeting. On the other hand, smooth-skin varieties frequently develop unsightly russeting in response to stress conditions, mainly high soil temperatures. Breeding programs in Israel aimed towards the improvement of heat tolerant varieties include skin quality as one of the desired characteristics. At the initiation of the present project it was unclear whether heat induced russeting and genetically inherited russeting share the same genes and biosynthesis pathways. Nevertheless, it has been suggested that russeting might result from increased periderm thickness, from strong cohesion between peridermal cells that prevents the outer layers from sloughing off, or from altered suberization processes in the skin. Hence, the original objectives were to conduct anatomical study of russet skin development, to isolate skin and russeting specific genes, to map the loci that determine the russet trait, and to compare with map locations the candidate russet specific genes, as well as to identify marker alleles that associated with russet loci. Anatomical studies suggested that russet may evolve from cracking at the outer layers of the skin, probably when skin development doesn’t meet the tuber expansion rate. Twodimensional gel electrophoresis and transcript profiling (cDNA chip, potato functional genomic project) indicated that in comparison to the parenchyma tissue, the skin is enriched with proteins/genes that are involved in the plant's responses to biotic and abiotic stresses and further expand the concept of the skin as a protective tissue containing an array of plantdefense components. The proteomes of skin from heat stressed tubers and native skin didn’t differ significantly, while transcript profiling indicated heat-related increase in three major functional groups: transcription factors, stress response and protein degradation. Exceptional was ACC synthase isogene with 4.6 fold increased level in the heat stressed skin. Russeting was mapped to two loci: rusB on chromosome 4 and rusC on chromosome 11; both required for russeting. No evidence was found for a third locus rusA that was previously proposed to be required for russeting. In an effort to find a link between the russeting character and the heat-induced russeting an attempt was made to map five genes that were found in the microarray experiment to be highly induced in the skin under heat stress in the segregating russet population. Only one gene was polymorphic; however it was localized to chromosome 2, so cannot correspond to rusB or rusC. Evaluation of AFLP markers tightly linked to rusB and rusC showed that these specific alleles are not associated with russeting in unrelated germplasm, and thus are not useful for MAS per se. To develop markers useful in applied breeding, it will be necessary to screen alleles of additional tightly linked loci, as well as to identify additional russet (heat-induced and/or native) related genes.
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Fait, Aaron, Grant Cramer i Avichai Perl. Towards improved grape nutrition and defense: The regulation of stilbene metabolism under drought. United States Department of Agriculture, maj 2014. http://dx.doi.org/10.32747/2014.7594398.bard.
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The goals of the present research proposal were to elucidate the physiological and molecular basis of the regulation of stilbene metabolism in grape, against the background of (i) grape metabolic network behavior in response to drought and of (ii) varietal diversity. The specific objectives included the study of the physiology of the response of different grape cultivars to continuous WD; the characterization of the differences and commonalities of gene network topology associated with WD in berry skin across varieties; the study of the metabolic response of developing berries to continuous WD with specific attention to the stilbene compounds; the integration analysis of the omics data generated; the study of isolated drought-associated stress factors on the regulation of stilbene biosynthesis in plantaand in vitro. Background to the topic Grape quality has a complex relationship with water input. Regulated water deficit (WD) is known to improve wine grapes by reducing the vine growth (without affecting fruit yield) and boosting sugar content (Keller et al. 2008). On the other hand, irregular rainfall during the summer can lead to drought-associated damage of fruit developmental process and alter fruit metabolism (Downey et al., 2006; Tarara et al., 2008; Chalmers et al., 792). In areas undergoing desertification, WD is associated with high temperatures. This WD/high temperature synergism can limit the areas of grape cultivation and can damage yields and fruit quality. Grapes and wine are the major source of stilbenes in human nutrition, and multiple stilbene-derived compounds, including isomers, polymers and glycosylated forms, have also been characterized in grapes (Jeandet et al., 2002; Halls and Yu, 2008). Heterologous expression of stilbenesynthase (STS) in a variety of plants has led to an enhanced resistance to pathogens, but in others the association has not been proven (Kobayashi et al., 2000; Soleas et al., 1995). Tomato transgenic plants harboring a grape STS had increased levels of resveratrol, ascorbate, and glutathione at the expense of the anthocyanin pathways (Giovinazzo et al. 2005), further emphasizing the intermingled relation among secondary metabolic pathways. Stilbenes are are induced in green and fleshy parts of the berries by biotic and abiotic elicitors (Chong et al., 2009). As is the case for other classes of secondary metabolites, the biosynthesis of stilbenes is not very well understood, but it is known to be under tight spatial and temporal control, which limits the availability of these compounds from plant sources. Only very few studies have attempted to analyze the effects of different environmental components on stilbene accumulation (Jeandet et al., 1995; Martinez-Ortega et al., 2000). Targeted analyses have generally shown higher levels of resveratrol in the grape skin (induced), in seeded varieties, in varieties of wine grapes, and in dark-skinned varieties (Gatto et al., 2008; summarized by Bavaresco et al., 2009). Yet, the effect of the grape variety and the rootstock on stilbene metabolism has not yet been thoroughly investigated (Bavaresco et al., 2009). The study identified a link between vine hydraulic behavior and physiology of stress with the leaf metabolism, which the PIs believe can eventually lead to the modifications identified in the developing berries that interested the polyphenol metabolism and its regulation during development and under stress. Implications are discussed below.
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Barash, Itamar, i Robert Rhoads. Translational Mechanisms Governing Milk Protein Levels and Composition. United States Department of Agriculture, 2006. http://dx.doi.org/10.32747/2006.7696526.bard.
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Original objectives: The long-term goal of the research is to achieve higher protein content in the milk of ruminants by modulating the translational apparatus of the mammary gland genetically, nutritionally, or pharmacologically. The short-term objectives are to obtain a better understanding of 1) the role of amino acids (AA) as regulators of translation in bovine and mouse mammary epithelial cells and 2) the mechanism responsible for the synergistic enhancement of milk-protein mRNA polyadenylation by insulin and prolactin. Background of the topic: In many cell types and tissues, individual AA affect a signaling pathway which parallels the insulin pathway to modulate rates and levels of protein synthesis. Diverse nutritional and hormonal conditions are funneled to mTOR, a multidomain serine/threonine kinase that regulates a number of components in the initiation and elongation stages of translation. The mechanism by which AA signal mTOR is largely unknown. During the current grant period, we have studied the effect of essential AA on mechanisms involved in protein synthesis in differentiated mammary epithelial cells cultured under lactogenic conditions. We also studied lactogenic hormone regulation of milk protein synthesis in differentiated mammary epithelial cells. In the first BARD grant (2000-03), we discovered a novel mechanism for mRNA-specific hormone-regulated translation, namely, that the combination of insulin plus prolactin causes cytoplasmic polyadenylation of milk protein mRNAs, which leads to their efficient translation. In the current BARD grant, we have pursued the signaling pathways of this novel hormone action. Major conclusions/solutions/achievements: The positive and negative signaling from AA to the mTOR pathway, combined with modulation of insulin sensitization, mediates the synthesis rates of total and specific milk proteins in mammary epithelial cells. The current in vitro study revealed cryptic negative effects of Lys, His, and Thr on cellular mechanisms regulating translation initiation and protein synthesis in mammary epithelial cells that could not be detected by conventional in vivo analyses. We also showed that a signaling pathway involving Jak2 and Stat5, previously shown to lead from the prolactin receptor to transcription of milk protein genes, is also used for cytoplasmic polyadenylation of milk protein mRNAs, thereby stabilizing these mRNAs and activating them for translation. Implications: In vivo, plasma AA levels are affected by nutritional and hormonal effects as well as by conditions of exercise and stress. The amplitude in plasma AA levels resembles that applied in the current in vitro study. Thus, by changing plasma AA levels in the epithelial cell microenvironment or by sensitizing the mTOR pathway to their presence, it should be possible to modulate the rate of milk protein synthesis. Furthermore, knowledge that phosphorylation of Stat5 is required for enhanced milk protein synthesis in response to lactogenic opens the possibility for pharmacologic approaches to increase the phosphorylation of Stat5 and, thereby, milk protein production.
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Horwitz, Benjamin, i Barbara Gillian Turgeon. Secondary Metabolites, Stress, and Signaling: Roles and Regulation of Peptides Produced by Non-ribosomal Peptide Synthetases. United States Department of Agriculture, 2005. http://dx.doi.org/10.32747/2005.7696522.bard.
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Fungal pathogens of plants produce a diverse array of small molecules. Often referred to as secondary metabolites because they were thought to be dispensable for basic functions, they may indeed have central roles as signals for the fungal cell, and in interactions with the host. We have identified more than a dozen genes encoding nonribosomal peptide synthetases (NPS) in Cochliobolusheterostrophus, the agent of southern corn leaf blight. The aim of this project was to identify roles of these genes in stress responses and signaling. The first objective was to test a complete collection of C. heterostrophus nonribosomal peptide synthetase (NRPS)-encoding gene deletion mutant and wildtype (WT) strains for sensitivity to various agents of oxidative (ROS) and nitrosative (RNOS) stress, in vitro. The second objective and next step in this part of the project was to study the relevance of sensitivity to ROS and RNOS in the host pathogen interaction, by measuring the production of ROS and RNOS in planta, when plants are inoculated with wild type and mutant strains. A third objective was to study expression of any genes shown to be involved in sensitivity to ROS or RNOS, in vitro and in planta. Another objective was to determine if any of the genes involved in oxidative or nitrosative stress responses are regulated by components of signal transduction pathways (STP) that we have identified and to determine where mechanisms overlap. Study of the collection of nps mutants identified phenotypes relevant for virulence, development and oxidative stress resistance for two of the genes, NPS2 and NPS6. Mutants in genes related to RNOS stress have no virulence phenotypes, while some of those related to ROS stress have reduced virulence as well as developmental phenotypes, so we focused primarily on ROS stress pathways. Furthermore, the identification of NPS2 and NPS6 as encoding for NRPS responsible for siderophore biosynthesis lent a new focus to the project, regulation by Fe. We have not yet developed good methods to image ROS in planta and work in this direction is continuing. We found that NPS6 expression is repressed by Fe, responding over the physiological Fe concentration range. Studying our collection of mutants, we found that conserved MAPK and G protein signal transduction pathways are dispensable for Fe regulation of NPS6, and initiated work to identify other pathways. The transcription factor SreA is one candidate, and is responsible for part, but not all, of the control of NPS6 expression. The results of this project show that the pathogen contends with oxidative stress through several signaling pathways. Loss of the siderophore produced by Nps6 makes the fungus sensitive to oxidative stress, and decreases virulence, suggesting a central role of the ability to sequester and take up extracellular iron in the host-pathogen interaction. Siderophores, and manipulation of Fe levels, could be targets for new strategies to deal with fungal pathogens of maize and other plants.
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Pell, Eva J., Sarah M. Assmann, Amnon Schwartz i Hava Steinberger. Ozone Altered Stomatal/Guard Cell Function: Whole Plant and Single Cell Analysis. United States Department of Agriculture, grudzień 2000. http://dx.doi.org/10.32747/2000.7573082.bard.
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Original objectives (revisions from original proposal are highlighted) 1. Elucidate the direct effects O3 and H2O2 on guard cell function, utilizing assays of stomatal response in isolated epidermal peels and whole cell gas exchange. 2. Determine the mechanistic basis of O3 and H2O2 effects on the plasma membrane through application of the electrophysiological technique of patch clamping to isolated guard cells. 3. Determine the relative sensitivity of Israeli cultivars of economically important crops to O3 and determine whether differential leaf conductance responses to O3 can explain relative sensitivity to the air pollutant: transfer of technological expertise to Israel. Background to the topic For a long time O3 has been known to reduce gas exchange in plants; it has however been unclear if O3 can affect the stomatal complex directly. Ion channels are essential in stomatal regulation, but O3 has never before been shown to affect these directly. Major conclusions, solution, achievements 1. Ozone inhibits light-induced stomatal opening in epidermal peels isolated from Vicia faba, Arabidopsis thaliana and Nicotiana tabacum in V. faba plants this leads to reduced assimilation without a direct effect on the photosynthetic apparatus. Stomatal opening is more sensitive to O3 than stomatal closure. 2. Ozone causes inhibition of inward K+ channels (involved in stomatal opening) while no detectable effect is observed o the outward K+ channels (stomatal closure). 3. Hydrogen peroxide inhibits stomatal opening and induces stomatal closure in epidermal peels isolated from Vicia faba. 4. Hydrogen peroxide enhances stomatal closure by increasing K+ efflux from guard cells via outward rectifying K+ channels. 5. Based on epidermal peel experiments we have indirectly shown that Ca2+ may play a role in the guard cell response to O3. However, direct measurement of the guard cell [Ca2+]cyt did not show a response to O3. 6. Three Israeli cultivars of zucchini, Clarita, Yarden and Bareqet, were shown to be relatively sensitive to O3 (0.12 ml1-1 ). 7. Two environmentally important Israeli pine species are adversely affected by O3, even at 0.050 ml1-1 , a level frequently exceeded under local tropospheric conditions. P. brutia may be better equipped than P. halepensis to tolerate O3 stress. 8. Ozone directly affects pigment biosynthesis in pine seedlings, as well as the metabolism of O5 precursors, thus affecting the allocation of resources among various metabolic pathways. 9. Ozone induces activity of antioxidant enzymes, and of ascorbate content i the mesophyll and epidermis cells of Commelina communis L. Implications, both scientific and agricultural We have improved the understanding of how O3 and H2O2 do affect guard cell and stomatal function. We have shown that economical important Israeli species like zucchini and pine are relatively sensitive to O3.