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Articles de revues sur le sujet "GNPAT"
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Phillips, John D., Colin P. Farrell, Jessica Overbey, Hetanshi Naik, Gordon D. McLaren, Christine E. McLaren, Luming Zhou et Charles J. Parker. « Identification of Polymorphic Gnpat As a Risk Factor for Porphyria Cutanea Tarda ». Blood 126, no 23 (3 décembre 2015) : 3353. http://dx.doi.org/10.1182/blood.v126.23.3353.3353.
Texte intégralRésumé :
Abstract Symptoms of porphyria cutanea tarda (PCT) resolve when iron stores are depleted by phlebotomy, and a sequence variant of HFE (C282Y) that increases iron absorption by reducing hepcidin expression is a risk factor for PCT. These observations suggest that PCT is an iron dependent disease and that factors that affect iron homeostasis influence the risk of developing the PCT. Recently, a polymorphic variant (D519G) of GNPAT was shown to be enriched in male patients with type I hereditary hemochromatosis (HFE C282Y homozygotes) who presented with a high iron phenotype [McLaren CE, et al. Hepatology Aug;62(2):429-39 2015]. Available evidence suggests that like HFE C282Y, GNPAT D519G increases iron absorption by reducing expression of hepcidin. Therefore, we investigated the prevalence GNPAT D519G in patients with PCT. The study population consisted of 247 patients with PCT. High-resolution DNA melting analysis and Taqman SNP assays were used to identify HFE (C282Y) and GNPAT (D519G) allelic variants, respectively and mutations in uroporphyrinogen decarboxylase (UROD) were identified by nucleotide sequencing. Patients with mutant UROD were categorized as familial PCT (F-PCT) (n=87, 36.0%) and those with wild-type UROD were categorized as sporadic PCT (S-PCT) (n=155, 64.0%). GNPAT D519G was significantly enriched in the patient population (prevalence 22.1%, p<0.001) compared to the general population (prevalence 13.6%) as was HFE C282Y (prevalence of 19.2% in the study population compared to 1.5% in the general population, p<0.001). The relative risk of GNPAT D519G was significantly increased in patients with F-PCT compared to those with S-PCT (odds ratio 1.81, CI 1.06-3.08) whereas the relative risk of HFE C282Y in the F-PCT was lower than in the S-PCT population (odds ratio 0.82, CI 0.46-1.47). Together, these observations suggest that GNPAT D519G, is more likely to require a cofactor (e. g., mutant UROD) to produce PCT whereas HFE C282Y functions as an independent PCT risk factor. This difference may be a consequence of the relative potency of GNPAT D519G (weak) and HFE C282Y (strong) with respect to effects on iron homeostasis. Our studies have identified a new risk factor (polymorphic GNPAT) for PCT that adds support for the involvement of aberrant iron metabolism in the pathobiology of PCT. Disclosures No relevant conflicts of interest to declare.
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McLaren, Gordon D., Mary J. Emond, V. Nathan Subramaniam, Pradyumna D. Phatak, James C. Barton, Paul C. Adams, Justin B. Goh et al. « Exome Sequencing Identifies a GNPAT Variant Associated with Severe Iron Overload in HFE C282Y Homozygous Men with Extreme Phenotypes ; Possible Role in Regulation of Hepcidin Expression ». Blood 124, no 21 (6 décembre 2014) : 745. http://dx.doi.org/10.1182/blood.v124.21.745.745.
Texte intégralRésumé :
Abstract Variability in the severity of iron overload among homozygotes for the HFE C282Y polymorphism is one of the major unsolved problems in our understanding of hereditary hemochromatosis (HH). We previously conducted exome sequencing of DNA from 35 HFE C282Y male homozygotes with either markedly increased iron stores (n=22; cases) or normal to mildly increased iron stores (n=13; controls) to identify rare and common causal variants associated with variability of disease expression in HH. The 35 participants, residents of the U.S., Canada, and Australia, reported little or no alcohol consumption. Criteria for HFE C282Y homozygotes with increased iron stores included serum ferritin >1000 µg/L at diagnosis and either (a) hepatic iron concentration >236 µmol/g dry weight (reference range 0-36 µmol/g) or (b) mobilized body iron >10 g by quantitative phlebotomy. Criteria for HFE C282Y homozygotes with normal or mildly elevated iron stores included (a) serum ferritin <300 µg/L or either (a) age ≥40 y with ≤2.5 g iron removed by phlebotomy to achieve serum ferritin <50 µg/L, or (b) age ≥50 y with ≤3.0 g iron removed by phlebotomy. After quality control filtering, sequencing data included 82,068 single nucleotide variants and 1,403 insertions/deletions (indels); 10,337 genes were tested for a difference between cases and controls. We identified the polymorphism GNPAT p.D519G (1556A>G; exon 11; chromosome 1q42; rs11558492) as the most significantly different variant between cases and controls (p=0.033 by the likelihood ratio test after correction for multiple comparisons). In a principal components analysis of ancestry, all 35 study participants were clustered closely together within a larger group of Europeans. Mean (SD) ages at presentation were 53 (11.5) y and 57 (10.0) y for cases and controls, respectively. Median serum ferritin was 2391 µg/L in cases and 302 μg/L in controls. The median transferrin saturation (96%) was greater in cases than controls (70%). Sixteen of 22 case participants had polymorphism GNPAT p.D519G (rs11558492) (15 heterozygotes, 1 homozygote); no control participant had this polymorphism. The homozygous case presented at age 26 y with severe iron overload but no cirrhosis. One GNPAT p.D519G heterozygote presented at age 36 y with severe iron overload and cirrhosis. GNPAT p.D519G is common among people of European descent (allele frequency 20.6%) and might interact with aberrant HFE to increase the risk of hepatic iron overload. More recently, we compared the allele frequencies of GNPAT p.D519G in the present 22 cases and 13 controls with that of 4300 European Americans in the NHLBI Exome Sequencing Project Exome Variant Server. The allele frequency in cases was greater than that of European Americans (38.6% vs. 20.6%, respectively; p = 0.0076). The allele frequency in controls was significantly lower (0% vs. 20.6%, p = 0.0054). Next, to determine whether other known mutations influenced iron phenotypes, the exome data were used to screen for mutations in HAMP, HJV, TFR2, FPN1, and TMPRSS6. One case participant was heterozygous for HJV p.G320V; he was among the six case participants who did not have GNPAT p.D519G. No other known or probable mutation that would possibly explain differences in expression between cases and controls was found. To examine functional consequences of GNPAT deficiency, we now have performed siRNA-based knockdown of GNPAT in the human liver cell line HepG2/C3A. GNPAT was efficiently knocked down by its siRNA by ~85% compared to control siRNA as assayed by qPCR. This knockdown resulted in a >17-fold decrease in HAMP mRNA expression. mRNA expression of two genes coordinately regulated with HAMP, ID1 (inhibitor of DNA binding protein 1) and SMAD7 (SMAD family member 7), was similarly decreased, as was expression of phospho-SMAD 1/5/8, suggesting that GNPAT knockdown affects the baseline activity of the bone morphogenetic protein 6 (BMP6)-SMAD pathway. Our data indicate that GNPAT p.D519G is associated with a high-iron phenotype in male HFE C282Y homozygotes and may participate in hepcidin regulation, thereby modifying severity of iron overload. The results identify GNPAT as a candidate gene for expanded studies to examine its function in regulating iron absorption and metabolism and to identify newly-diagnosed C282Y homozygotes whose risk for development of severe iron overload is great. Disclosures No relevant conflicts of interest to declare.
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Azad, Abul Kalam, Abdullah Md Sheikh, Md Ahsanul Haque, Harumi Osago, Hiromichi Sakai, Abu Zaffar Shibly, Shozo Yano et al. « Time-Dependent Analysis of Plasmalogens in the Hippocampus of an Alzheimer’s Disease Mouse Model : A Role of Ethanolamine Plasmalogen ». Brain Sciences 11, no 12 (2 décembre 2021) : 1603. http://dx.doi.org/10.3390/brainsci11121603.
Texte intégralRésumé :
Plasmalogens are alkenyl-acyl glycerophospholipids and decreased in post-mortem Alzheimer’s disease (AD) brains. The aim of this study is to investigate the time-dependent changes of plasmalogens in the hippocampus of an AD model mouse (J20). Plasmalogen levels at 3, 6, 9, 12 and 15 months were analyzed by liquid-chromatography-targeted-multiplexed-selected-reaction-monitoring-tandem-mass-spectrometry (LC-SRM/MS). Reactive oxygen species (ROS) levels were evaluated using dichlorofluorescein diacetate (DCF-DA). Plasmalogen synthesizing enzyme glycerone-phosphate O-acyltransferase (GNPAT) and late endosome marker Rab7 levels were quantified by Western blotting. GNPAT localization, changes of neuronal and glial cell numbers were evaluated by immunostaining. Compared to wild-type mice (WT), total plasmalogen-ethanolamine, but not plasmalogen-choline levels, were increased at 9 months and subsequently decreased at 15 months in J20 mice. A principal component analysis of plasmalogen-ethanolamine species could separate WT and J20 mice both at 9 and 15 months. Both GNPAT and Rab7 protein were increased in J20 mice at 9 months, whereas GNPAT was decreased at 15 months. ROS levels were increased in J20 mice except for 9 months. Our results suggest that increased plasmalogen-ethanolamine could counteract ROS levels and contribute to the phagocytosis process in J20 mice at 9 months. Such results might indicate a transient protective response of plasmalogen-ethanolamine in AD conditions.
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Tachon, Gaelle, Marie-Paule Roth, Fabienne Calcoen, Celine Besson-Fournier, Michael Bismuth et Patricia Aguilar-Martinez. « Phenotypic Variability in Genetic Hemochromatosis : Study of Five SNPs in a Cohort of 342 Compound Heterozygotes for the HFE Cys282Tyr / His63Asp Mutations ». Blood 126, no 23 (3 décembre 2015) : 3361. http://dx.doi.org/10.1182/blood.v126.23.3361.3361.
Texte intégralRésumé :
Abstract The HFE p.Cys282Tyr (C282Y) mutation is the disease-causing defect in most cases of genetic hemochromatosis, but involvement of the p.His63Asp (H63D) variant in the pathogenesis of the illness is still a matter of debate. Some authors consider C282Y/H63D (YD) subjects as at risk of developing hemochromatosis, whereas others argue that iron overload, seen in some of these subjects, is related to external factors. As for the C282Y homozygotes, genetic modifiers might contribute to the phenotypic variability of hemochromatosis in YD subjects. This work was thus aimed at assessing the possible influence of Single Nucleotide Polymorphism (SNPs) suspected to play a role in iron metabolism on disease expression in compound heterozygotes. We genotyped five SNPs in 342 YD unrelated Caucasian patients (208 males, 134 females) from South France. Information on demographics, clinical manifestations, laboratory tests, viral status and alcohol consumption was obtained from the medical records of the participants. The selected SNPs were already described as modifiers of iron overload by previous studies. They are located in the TMPRSS6 (rs855791 and rs4820268), TF (rs3811647), CYBRD1 (rs884409) and GNPAT (rs11558492) genes. The role of GNPAT in iron metabolism is unknown but it has been recently associated with the severity of the clinical expression in C282Y homozygous subjects1. Analysis of the SNPs was performed using Endpoint TaqMan Genotyping technology. For each SNP, the additive effect of the minor allele on the logarithm of serum ferritin (SF) was first assessed through a linear regression, controlling for age, sex, alcohol consumption, and patient's referral motive. We found a marginally significant association between rs884409 allele G of CYBRD1 and SF (p = 0.014). In a second step, we restricted our analysis to the 77 most severe males (SF > 500 µg/l and no past or current history of alcohol consumption > 20g/day), and found that the GNPAT rs11558492 allele G was significantly enriched in this subset. Indeed, 8 subjects were homozygous for allele G and 40 were heterozygous AG. G allele frequency in these 77 males was 36%, which is higher than the 19% found in the individuals from Northwest Europe (CEU) used for the HapMap project (p<0.0001) and the 21% reported in 4300 European Americans from the National Heart, Lung, and Blood Institute (NHLBI) Exome Sequencing Project (p <0.0001). It is also higher than in the 26% found in the rest of the YD cohort (p=0.0029) which includes a large number of younger subjects recruited because of family history of hemochromatosis and of premenopausal women whose severity on the long term is difficult to assess. In conclusion, our study draws attention to two SNPs (rs884409 and rs11558492) in genes DCYTB and GNPAT, respectively, that are appear to worsen the phenotypic expression of YD patients. These results also support the hypothesis that GNPAT plays a still undiscovered role in iron homeostasis. 1. McLaren, C. E. et al. Exome sequencing in HFE C282Y homozygous men with extreme phenotypes identifies a GNPAT variant associated with severe iron overload. Hepatol. Baltim. Md (2015). doi:10.1002/hep.27851 The authors are grateful to the members of the "Centre de competence" on rare iron disorders of CHU de Montpellier Disclosures No relevant conflicts of interest to declare.
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Dorninger, Fabian, Attila Kiss, Peter Rothauer, Alexander Stiglbauer-Tscholakoff, Stefan Kummer, Wedad Fallatah, Mireia Perera-Gonzalez et al. « Overlapping and Distinct Features of Cardiac Pathology in Inherited Human and Murine Ether Lipid Deficiency ». International Journal of Molecular Sciences 24, no 3 (18 janvier 2023) : 1884. http://dx.doi.org/10.3390/ijms24031884.
Texte intégralRésumé :
Inherited deficiency in ether lipids, a subgroup of glycerophospholipids with unique biochemical and biophysical properties, evokes severe symptoms in humans resulting in a multi-organ syndrome. Mouse models with defects in ether lipid biosynthesis have widely been used to understand the pathophysiology of human disease and to study the roles of ether lipids in various cell types and tissues. However, little is known about the function of these lipids in cardiac tissue. Previous studies included case reports of cardiac defects in ether-lipid-deficient patients, but a systematic analysis of the impact of ether lipid deficiency on the mammalian heart is still missing. Here, we utilize a mouse model of complete ether lipid deficiency (Gnpat KO) to accomplish this task. Similar to a subgroup of human patients with rhizomelic chondrodysplasia punctata (RCDP), a fraction of Gnpat KO fetuses present with defects in ventricular septation, presumably evoked by a developmental delay. We did not detect any signs of cardiomyopathy but identified increased left ventricular end-systolic and end-diastolic pressure in middle-aged ether-lipid-deficient mice. By comprehensive electrocardiographic characterization, we consistently found reduced ventricular conduction velocity, as indicated by a prolonged QRS complex, as well as increased QRS and QT dispersion in the Gnpat KO group. Furthermore, a shift of the Wenckebach point to longer cycle lengths indicated depressed atrioventricular nodal function. To complement our findings in mice, we analyzed medical records and performed electrocardiography in ether-lipid-deficient human patients, which, in contrast to the murine phenotype, indicated a trend towards shortened QT intervals. Taken together, our findings demonstrate that the cardiac phenotype upon ether lipid deficiency is highly heterogeneous, and although the manifestations in the mouse model only partially match the abnormalities in human patients, the results add to our understanding of the physiological role of ether lipids and emphasize their importance for proper cardiac development and function.
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Secondes, Eriza S., Daniel F. Wallace, Gautam Rishi, Gordon D. McLaren, Christine E. McLaren, Wen-Pin Chen, Louise Ramm et al. « Increased Allele Frequency of GNPAT p.D519G in Compound HFE p.C282Y/p.H63D Heterozygotes with Elevated Serum Ferritin Levels ». Blood 134, Supplement_1 (13 novembre 2019) : 4807. http://dx.doi.org/10.1182/blood-2019-128240.
Texte intégralRésumé :
In hemochromatosis, iron overload is due to increased intestinal iron absorption attributable to mutations in several genes involved in the regulation of iron absorption and metabolism. The most common type of hemochromatosis is caused by mutations in the HFE gene, and homozygosity for the HFE p.C282Y mutation is associated with a risk of iron overload. Approximately 1:200 people of Caucasian origin are homozygous for p.C282Y, but only a minority of p.C282Y homozygotes develop significant iron overload. This is attributed in part to the presence of putative genetic modifiers of iron absorption. Recently, we identified GNPAT, encoding glyceronephosphate O-acyltransferase, as a potential modifier of HFE hemochromatosis in a whole-exome sequencing study of p.C282Y homozygotes with extreme iron overload phenotypes. A GNPAT polymorphism (p.D519G, rs11558492) was associated with severe iron overload among p.C282Y homozygous men (Hepatology 2015;62:429-39). Other studies have either substantiated or contradicted the importance of GNPAT p.D519G as a genetic modifier of iron phenotypes in HFE p.C282Y homozygotes. p.D519G is also a risk factor for familial (but not sporadic) porphyria cutanea tarda (Plos One 2016;11:e0163322). Some patients with hemochromatosis phenotypes are heterozygous for p.C282Y and a different HFE polymorphism, p.H63D (which is also common but usually not itself associated with clinically significant iron overload). Many p.C282Y/p.H63D compound heterozygotes have milder iron overload phenotypes than p.C282Y homozygotes. Herein, we report studies of the prevalence of p.D519G in a cohort of compound heterozygous p.C282Y/p.H63D Australian patients, with or without elevated serum ferritin (SF) levels. We also compared p.D519G allele frequency of the present p.C282Y/p.H63D compound heterozygotes with those of large population cohorts. We identified 72 HFE p.C282Y/p.H63D compound heterozygotes with DNA available for analysis. Of these, 9 had missing SF data and were excluded. GNPAT p.D519G was assessed in the remaining 63 subjects. Compound heterozygotes with elevated SF levels ≥300 µg/mL (males) and ≥200 µg/mL (females) were selected as cases (n=28), and participants with SF levels below these cut-offs were classified as controls (n=35). The mean age at the time of testing was 31 y (males 31, females 31) in the control group and 48 y (males 47, females 51) in subjects with elevated SF levels. Among cases, mean SF was 612 µg/L (median 557 µg/L, IQR 361- 821 µg/L). Mean SF in the control group was 85 µg/L (median 58 µg/L, IQR 38 - 121 µg/L). All samples were genotyped for GNPAT p.D519G. We compared the p.D519G allele frequency of the present subjects, with and without elevated SF, to the p.D519G frequency in publically available datasets. p.D519G allele frequency was greater in the elevated SF group (37.5%) than the control group (24.3%), but this difference was not significant (p=0.1285). p.D519G was more prevalent in our cohort of p.C282Y/p.H63D compound heterozygotes with elevated SF (37.5%) than in European populations reported in public datasets: ExAC 19.7%, 1000G 21.3%, gnomAD 20.4%, and ESP 20.6%. There was a significant association between allele count and case/control status among men (type 3 analysis of effects; p = 0.049) but not women. For a male case, the odds of having either 1 or 2 alleles versus having 0 alleles was 5.08 (95% CI, 1.01, 25.66) times higher than that of a male control. In conclusion, our results demonstrate that GNPAT p.D519G is associated with elevated SF levels in Australian HFE p.C282Y/p.H63D compound heterozygotes and that the p.D519G allele frequency is greater in p.C282Y/p.H63D compound heterozygotes with elevated SF than in several large European population cohorts. We found a statistically significant association between the allele count and the case/control status among men. The small number of subjects with elevated SF in our study may have limited our ability to demonstrate significant differences in some comparisons. Some subjects with p.D519G do not have elevated SF, suggesting that there are other factors, genetic or environmental, which also affect iron absorption in p.C282Y/p.H63D compound heterozygotes. Disclosures No relevant conflicts of interest to declare.
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Valcárcel, Luis Vitores V., Raquel Ordoñez, Iñigo Apaolaza, Ana Valcárcel, Leire Garate, Cem Meydan, Bruno Paiva et al. « Computational Systems Biology Models for the Identification of Metabolic Vulnerabilities in Multiple Myeloma ». Blood 134, Supplement_1 (13 novembre 2019) : 3084. http://dx.doi.org/10.1182/blood-2019-123970.
Texte intégralRésumé :
Multiple myeloma (MM) is a hematological malignancy characterized by an abnormal accumulation of clonal plasma cells in the bone marrow. MM heterogeneity is associated to the presence of different genomic and transcriptomic profiles that have a clear impact on the prognosis of the disease. Metabolism has been deeply studied in cancer research, unveiling several vulnerabilities in different tumors. However, information regarding the role of metabolism in the pathogenesis of MM has not been explored in detail. Previous studies from our group using Systems Biology approach, explained the essentiality of metabolic gene RRM1 in several MM cell lines. The aim of our current study was to identify metabolic vulnerabilities in MM based on the application of a system biology approach focus on metabolic networks and trascriptomic data from MM patients. Our hypothesis being that changes in the metabolic landscape of MM could be exploited to uncover novel targets for prognosis and treatment in MM patients. We have analyzed the strand specific RNA-seq data from 35 samples from different subpopulations of B cells (Naïve, Centroblast, Centrocyte, Memory, Tonsilar and Bone Marrow Plasma cells (PCs)) and PCs of 37 MM patient samples. Using only the expression of 3287 metabolic genes included in Recon3D, the latest human metabolic reconstruction, we identified metabolic transcription patterns that clearly differentiate the different B cells from MM plasma cells (Figure 1A). MM samples were more similar to the normal PCs than to other B cells, which suggest that they maintain part of the metabolic pattern of the PCs, but in turn showed significant differences in the expression of metabolic genes. Interestingly, differential expression analysis of metabolic genes in MM PCs revealed a decrease in the expression of genes involved in mitochondrial activity and an increase in those that participate in metabolic proliferation, indicating that these alterations could probably play an important role in the development of this tumor. Using our novel systems biology approach, based on Recon3D and transcriptomic profiles, we predicted essential genes and synthetic lethals (involving two or more genes) that were specific for MM patients and not for the rest of the B cell subpopulations. Our approach makes use of the concept of genetic Minimal Cut Sets, previously introduced by our group in cancer research, which defines subsets of genes that if knocked out at the same time, induce a blockage of cellular proliferation. A metabolic vulnerability is found when only one gene is highly expressed in one of these gMCSs. We also analyzed the essentiality of these genes in more than 500 MM patients samples included in CoMMpass project and MM cell lines analyzed in Cancer Cell Line encyclopedia (CCLE). Using this computational strategy, we detected 8 essential genes involved in 42 gMCS specific for MM patients. From those candidates, GNPAT was our most promising target gene, as it was predicted to be essential for more than 40% of MM patients in our group, approximately 10% of patients of CoMMpass and in the majority of MM cell lines (Figure 1B). Validation of GNPAT expression and other 18 genes involved in the GNPAT gMCS was carried out by RT-qPCR showing similar results that were obtained with our RNA-seq data. Interestingly, the expression of the partner genes included in the GNPAT gMCS, such as DGK gene family, could also be indicators of the effectiveness of knocking-out, where their high expression is an indicator of resistance and their low expression an indicator of sensitivity. In conclusion, our findings suggest that our systems biology computational approach, driven by RNA-seq data, identifies metabolic vulnerabilities (defined as essential genes or synthetic lethal genes) providing pairs of new targets (essential gene) and their associated biomarkers (gMCS) in patients with MM. Figure 1: Metabolic genes expression analysis in human humoral immune response and MM patient samples. A) Standardized PCA result using the expression of metabolic genes included in Recon3D, in distinct subpopulations of B cells and MM samples. B) GNPAT gMCS showing the expression (in TPM) of GNPAT and associated 18 genes in MM cell lines. Figure 1 Disclosures Paiva: Amgen, Bristol-Myers Squibb, Celgene, Janssen, Merck, Novartis, Roche, and Sanofi; unrestricted grants from Celgene, EngMab, Sanofi, and Takeda; and consultancy for Celgene, Janssen, and Sanofi: Consultancy, Honoraria, Research Funding, Speakers Bureau. Melnick:Epizyme: Consultancy; KDAc Therapeutics: Membership on an entity's Board of Directors or advisory committees; Constellation Pharmaceuticals: Consultancy; Janssenn: Research Funding. San-Miguel:Amgen, Bristol-Myers Squibb, Celgene, Janssen, MSD, Novartis, Roche, Sanofi, and Takeda: Consultancy, Honoraria.
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McLaren, Christine E., Mary J. Emond, Pradyumna D. Phatak, Paul C. Adams, V. Nathan Subramaniam, James C. Barton, Lawrie W. Powell et al. « Exome Sequencing Identifies Genes and Variant Alleles Associated With Severity Of Iron Overload In Hemochromatosis HFE C282Y Homozygotes ». Blood 122, no 21 (15 novembre 2013) : 179. http://dx.doi.org/10.1182/blood.v122.21.179.179.
Texte intégralRésumé :
Abstract Variability in the severity of iron overload among homozygotes for the HFE C282Y polymorphism is one of the major problems extant in our understanding of hereditary hemochromatosis (HH). We conducted exome sequencing of DNA from C282Y homozygotes with markedly increased iron stores (cases) and C282Y homozygotes with normal or mildly increased iron stores (controls) to identify rare and common causal variants associated with variability of disease expression in HH. Criteria for cases included serum ferritin >1000 µg/L at diagnosis, and (a) mobilized body iron >10 g by quantitative phlebotomy, and/or (b) hepatic iron concentration >236 µmol/g dry weight. Criteria for controls included (a) serum ferritin <300 µg/L, or (b) age ≥50 y with ≤3.0 g iron removed by phlebotomy or age ≥40 y with ≤2.5 g iron removed by phlebotomy to achieve serum ferritin <50 µg/L. Deep sequencing of the full exome was performed in 33 cases and 14 controls. After quality control filtering, the dataset included 82,068 SNPs and 1,403 insertions/deletions (indels). Our initial analysis tested for differences in the distribution of variants between groups for each gene separately using the Sequence Kernel Association Test (SKAT) that includes rare and common variants but downweights the contribution of common variants to the test statistic. Only non-synonymous variants were included in the by-gene tests. Principal components were constructed from the exome variants to adjust for possible confounding by ancestry and to confirm no ancestral outliers. All study participants were male, and all clustered closely together within a larger group of Europeans in a principal components analysis of ancestry. Mean (SD) ages at presentation were 54 (11.0) y and 56 (9.4) y for cases and controls, respectively. Median serum ferritin was 2788 µg/L in those with increased iron stores and 309 μg/L in those with normal or mildly increased iron stores. The median transferrin saturation (94%) was greater in cases than in the comparison group (70%). In a preliminary analysis, we found 9 genes associated with case-control status. To separate effects of alcohol use and/or alcohol addiction variants, an analysis was conducted to compare the 13 controls and 22 cases who reported never using alcohol or only very light use. The two most significant genes identified in this comparison were GNPAT (p=7.4x10-6) and CDHR2 (p=2.8x10-4). A quantile-quantile (QQ) plot is shown in the Figure, comparing the observed distribution of –(log10p-values) from 10,337 genes to the expected uniform distribution if there were no variants modifying severity of expression, and gives evidence of the effect of the GNPAT gene.Figure 1Figure 1. Inspection of the two variants contributing to the GNPAT by-gene p-value revealed one missense variant (rs11558492) for which 0/13 controls had a polymorphism, while 16/22 cases had at least one missense variant, and one case was homozygous for this missense variant. The latter case presented at the early age of 26 with a serum ferritin of 1762 µg/L, 4+ hepatocellular iron and hepatic iron concentration of 284.4 µmol/g dry weight. GNPAT (aka DHAPAT) mutations/deletions have been found in peroxisomal disease, a class of diseases in which increased hepatic iron is observed (Biochim Biophys Acta 1801:272-280, 2010). GNPAT rs11558492 is common among people of European descent but might interact with aberrant HFE to increase risk of hepatic iron overload. Three rare variants in CDHR2 accounted for its low p-value, having a cumulative frequency of 4/13 among controls and 0/22 among cases: rs115050587, rs752138, rs143224505 with minor allele frequencies, MAF = 1.4%, 4.7% and 0.06%, respectively. The first two polymorphisms are predicted to be highly damaging by PolyPhen2 and the third probably damaging. Expression levels of CDHR2 recently have been associated with increased hepatocyte iron and elevated serum ferritin in liver allograft patients (J Clin Invest 122:368-382, 2012). These data indicate associations between iron status in HFE C282Y homozygotes and genes with previous links to iron overload that may modify severity of disease expression. Of note, the data suggest that more than one modifier gene may be involved in determining severity of disease in HFE C282Y homozygotes. Our results identify candidate genes for expanded studies that would examine their functional significance for iron absorption and metabolism. Disclosures: No relevant conflicts of interest to declare.
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Rametta, Raffaela, Paola Dongiovanni, Silvia Fargion et Luca Valenti. « GNPAT p.D519G variant and iron metabolism during oral iron tolerance test ». Hepatology 65, no 1 (24 août 2016) : 384–85. http://dx.doi.org/10.1002/hep.28745.
Texte intégral
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Dorninger, Fabian, Anna Gundacker, Gerhard Zeitler, Daniela D. Pollak et Johannes Berger. « Ether Lipid Deficiency in Mice Produces a Complex Behavioral Phenotype Mimicking Aspects of Human Psychiatric Disorders ». International Journal of Molecular Sciences 20, no 16 (13 août 2019) : 3929. http://dx.doi.org/10.3390/ijms20163929.
Texte intégralRésumé :
Ether lipids form a specialized subgroup of phospholipids that requires peroxisomes to be synthesized. We have previously detected that deficiency in these lipids leads to a severe disturbance of neurotransmitter homeostasis and release as well as behavioral abnormalities, such as hyperactivity, in a mouse model. Here, we focused on a more detailed examination of the behavioral phenotype of ether lipid-deficient mice (Gnpat KO) and describe a set of features related to human psychiatric disorders. Gnpat KO mice show strongly impaired social interaction as well as nestlet shredding and marble burying, indicating disturbed execution of inborn behavioral patterns. Also, compromised contextual and cued fear conditioning in these animals suggests a considerable memory deficit, thus potentially forming a connection to the previously determined ether lipid deficit in human patients with Alzheimer’s disease. Nesting behavior and the preference for social novelty proved normal in ether lipid-deficient mice. In addition, we detected task-specific alterations in paradigms assessing depression- and anxiety-related behavior. The reported behavioral changes may be used as easy readout for the success of novel treatment strategies against ether lipid deficiency in ameliorating nervous system-associated symptoms. Furthermore, our findings underline that ether lipids are paramount for brain function and demonstrate their relevance for cognitive, social, and emotional behavior. We hereby substantially extend previous observations suggesting a link between deficiency in ether lipids and human mental illnesses, particularly autism and attention-deficit hyperactivity disorder.
Thèses sur le sujet "GNPAT"
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GRENI, FEDERICO. « Variabilità fenotipica nell'emocromatosi : studio di due potenziali modificatori genetici in PCSK7 e GNPAT ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2017. http://hdl.handle.net/10281/140994.
Texte intégralRésumé :
Introduction and aim: Hereditary hemochromatosis (HH) is a genetic disease characterized by a progressive iron overload in different tissues. Homozygosity for the p.C282Y mutation is the most frequent genotype associated with the disease and it is directly responsible for an inappropriate production of hepcidin, the main regulator of iron homeostasis. Several evidences indicated that p.C282Y homozygous genotype has an incomplete penetrance due to the combined action of genetic and acquired modifier factors. Recently, the attention was focused on GNPAT rs11558492 and PCSK7 rs236918 single nucleotide polymorphisms (SNPs). The aim of my thesis was to analyse the role of these potential genetic modifiers in an Italian cohort of p.C282Y homozygotes.
Materials and methods: Patients: 298 patients (205 males and 93 females) and 169 healthy controls. Exclusion criteria were: alcohol intake >50 g/day in men and >30 g/day in women, chronic hepatitis, inflammatory status. SNPs genotyping was performed by ARMS-PCR or PCR-RFLP. Random samples were confirmed by direct sequencing. Patients and controls allelic and genotypic frequencies were compared to EVS database and analysed according to serum ferritin levels (SF), liver iron concentration (LIC) measured by liver biopsy or magnetic resonance, iron removed (IR) and liver fibrosis histologically assessed by Ishak score (IS). Fisher’s exact test, chi-squared test and t-test were used to perform statistical comparisons between groups and averages of considered variables.
Results: GNPAT rs11558492 analysis. Our results demonstrated that: a. allelic and genotypic frequencies were comparable among patients, controls and EVS data. No significant differences were found even considering two subgroups of males only with extreme phenotypes (SF <1000 mcg/L, IR <5 g and/or LIC <100 mcmol/g vs SF >2000 mcg/L, IR >10 g and/or LIC> 50 mcmol/g); b. according to iron indices, allelic and genotypic frequencies did not significantly differ neither among patients nor compared to controls, limited to SF; c. similarly, minor allele (G) frequency did not differ between patients with absent/mild fibrosis and patients with severe fibrosis/cirrhosis (20.5% vs 25%).
PCSK7 rs236918 analysis. Our study demonstrated that: a. minor allele (C) frequency was higher in patients with severe fibrosis/cirrhosis than in patients with absent/mild fibrosis (21.9% vs 7.1%; p=0.003); b. C-allele carriers were more likely to have worse liver staging scores than wild-type patients (OR=2.77, p=0.0018; ORmale-only=2.56, p=0.0233); c. PCSK7 genotype has a direct effect on severe fibrosis/cirrhosis (OR=3.11, p=0.0157) and a mild nonsignificant indirect effect mediated through SF and IR (mediation analysis: 22% and 28%, respectively).
Conclusions: Our results demonstrated that: a. GNPAT rs11558492 is not a major modifier of iron status in HH patients and controls, and is not associated with severe fibrosis/cirrhosis in HH patients. b. PCSK7 rs236918 C allele is a risk factor for cirrhosis development in Italian HH patients.
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Correia, Bárbara Catarina Gonçalves. « Determinig how membrane phospholipids regulate CNS myelination and myelin composition ». Master's thesis, Universidade de Aveiro, 2017. http://hdl.handle.net/10773/22236.
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Mestrado em Biologia Molecular e CelularRhizomelic chondrodysplasia punctata (RCDP) is an autosomal recessive disorder characterized by a defect in peroxisomal enzymes responsible for the biosynthesis of plasmalogens. This leads to a deficiency of this type of glycerophospholipid, and patients present bone abnormalities, and mental retardation. This disorder can be caused by mutations in the GNPAT gene, which encodes the first enzyme necessary for plasmalogen synthesis. Some studies have shown that myelination in the peripheral and central nervous system is affected by the loss of plasmalogens. However, it is unknown how this defect in myelination is orchestrated in a cellular and molecular scenario. With this work, we showed that it is possible to use in vitro co-cultures of cortical neurons and oligodendrocytes, from WT and Gnpat KO mice, to investigate the relation between both cells and what leads to demyelination. This strategy can also help to test different candidates for therapies. Alkyl-glycerols have been indicated as an alternative precursor of plasmalogens, but until now their efficiency to restore plasmalogen levels is still not proven in nervous tissue. We used one type of alkyl-glycerol named 1-O-tetradecyl-glycerol, and it was able to restore the defective myelination in Gnpat KO co-cultures. Myelin is also rich in proteins, and some have important functions for compaction and maintenance of the myelin sheaths. Therefore, it is important to analyze how the proteins are affected by the lack of plasmalogens. We used Western blot to analyze different proteins present in compact and non-compact myelin. We observed a significant decrease in the amount of myelin basic proteins (MBP) in myelin isolated from brain and spinal cord of Gnpat KO mice. MBP is essential to keep the myelin sheaths compact and functional. Other proteins like tubulin polymerization-promoting protein (TPPP) showed no differences in brain or in spinal cord myelin, since this protein is known to regulate the differentiation of oligodendrocytes, and our previous results did not evidence any problems during differentiation.
Condrodisplasia rizomélica puncata é uma doença autossómica recessiva caracterizada por um defeito em enzimas peroxisomais responsáveis pela biossíntese de plasmalogénios. Estes defeitos causam uma deficiência na produção deste fosfolípido e os doentes apresentam anormalidades ósseas e um atraso mental. Esta doença pode ser causada por mutações no gene que codifica a enzima GNPAT que é a primeira enzima necessária para a síntese de plasmalogénios. Alguns estudos demonstraram que a mielinização é afetada pela perda de plasmlalogéneos no sistema nervoso central e periférico. Contudo, ainda não se sabe como é que este defeito se processa a nível celular e molecular. Com o presente trabalho, demonstramos que é possível usar co-culturas in vitro de neurónios corticais e de oligodendrócitos, provenientes de ratinhos wildtype (WT) e knockout (KO), possibilitando a investigação da relação entre os dois tipos de células e o que origina a desmielinização observada in vivo. Este método in vitro também pode ser usado para testar diferentes candidatos para eventuais terapias. Os alquil-glicerois já foram indicados como um percursor alternativo de plasmalogénios, mas a sua eficácia nunca foi comprovada em tecidos neuronais. Neste trabalho usámos um tipo de alquil-glicerol, denominado 1-O-tetradecil-glicerol, capaz de restaurar os defeitos da mielina nas co-culturas de ratinhos Gnpat KO. A mielina é também rica em proteínas e algumas têm funções importantes na compactação e manutenção da mielina. Por esse motivo, é importante estudar como é que as proteínas da mielina são afetadas pela deficiência em plasmlalogéneos. O western blot foi usado para analisar as diferentes proteínas presentes tanto na mielina compacta como na mielina não compacta. Os resultados demonstraram um decréscimo significativo da proteína básica de mielina (MBP) em mielina isolada do cérebro e espinal medula de ratinhos KO. Esta proteína é essencial para manter os segmentos de mielina compactos e funcionais. A proteína promotora de polimerização de tubulina (TPPP) não demonstrou diferenças, quer em mielina do cérebro quer da espinal medula. Esta proteína é responsável por regular a diferenciação dos oligodendrócitos e os nossos resultados mostram que um defeito em plasmalogénios não afeta a diferenciação dos oligodendrócitos, mas especificamente a produção de mielina por estas células.
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Bealmear, Stacey. « Fungus Gnat Integrated Pest Management ». College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2010. http://hdl.handle.net/10150/144781.
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Biktchourina, Angelina. « Les verbes gnat' / gonjat' : sémantique, catégorie grammaticale, dérivation et phraséologie ». Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE3030/document.
Texte intégralRésumé :
Dans cette thèse, nous avons étudié d’une manière structurée et détaillée la sémantique des verbes gnat’ et gonjat’. Pour cela, nous avons tout d’abord formalisé leur potentiel sémantique qui comprend les composants de leur valeur de base et ce qu’ils génèrent dans des situations nouvelles, dans des cotextes particuliers. Pour chaque valeur sémantique, nous avons présenté un schéma sémantique, un schéma actantiel en précisant les rôles sémantiques, la nature des actants et leur réalisation syntaxique, ainsi que des illustrations d’emploi dans des cotextes des plus représentatifs, des synonymes, la famille morphologique. Les valeurs plus ou moins communes à gnat’ et à gonjat’ ont été étudiées ensemble, ce qui nous a permis de mettre en évidence leurs similitudes et différences. Puis, nous avons traité la question de la catégorie grammaticale des verbes de mouvement. Après avoir exposé les propriétés traditionnellement attribuées aux corrélats déterminé / indéterminé et les particularités qui sont générées dans l’emploi de chacun de ces corrélats, nous avons analysé la corrélation déterminé / indéterminé en général, et en particulier, entre gnat’ et gonjat’. Faisant partie de la catégorie grammaticale des verbes de mouvement, gnat’ et gonjat’ s’opposent sur le plan grammatical en tant que déterminé vs indéterminé et leurs caractéristiques grammaticales induisent quelques différences sémantiques. Ainsi, la plupart des différences observées entre gnat’ et gonjat’ ne sont pas en fait pas d’ordre lexical, mais résultent des différences grammaticales du déterminé gnat’ et de l’indéterminé gonjat’. Dans la partie consacrée à la dérivation morphologique, nous avons eu pour objectif d’examiner les effets de la préverbation et les modifications de sens que la préverbation entraîne pour ces verbes. Nous avons étudié les préverbés formés sur la base de gnat’ / gonjat’ à valeur spatiale en les regroupant en fonction de l’orientation spatiale : à partir du point de départ, vers le point d’arrivée, les deux en même temps ou en rapport avec un repère. Une attention minutieuse a été accordée aux différences sémantiques et aspectuelles de certains préverbés partageant les mêmes valeurs spatiales. L’étude des préverbés combinés aux préverbes à valeur non spatiale a été organisée en fonction de la morphologie de l’aspect : les préverbés hors couple et les couples de verbes. Quelques particularités ont été observées. Pour que l’étude sémantique soit complète, nous y avons inclus la question des phrasèmes comportant ces verbes. Puis, nous avons analysé le parallélisme qui existe entre gnat’ / gonjat’ simples et préverbés et le verbe dit de position sidet’ : les valeurs que ces verbes ont en commun et aussi, les limites de leur corrélation, Enfin, en partant directement des situations linguistiques concrètes avec gnat’ / gonjat’ simples et préverbés nous avons exposé un certain nombre de mécanismes qui aboutissent à un effet expressifIn this thesis, we have studied the semantics of the verbs gnat’ and gonjat’ in a structured and extensive way. To achieve this, we began by structuring their semantic potential, which includes their basic value and what it produces in new situations, in specific cotexts. For each semantic value, we have presented a semantic schema, mapping the semantic roles of the actants, their nature and their syntactic development, together with examples of usage in the most representative cotexts, the synonyms, the morphological family. The more or less common values of gnat’ and gonjat’ have been studied together, so that we could bring their similarities and differences to light. Then, we dealt with the question of the grammatical category of the verbs of motion. Having presented the usually attributed properties of the correlate determined / indetermined and the particularities that emerge in the usage of each of these correlates, we have focused on the determined / indetermined correlation in general and between gnat’ and gonjat’ in particular. While belonging to the same grammatical category of the verbs of motion, both gnat’ and gonjat’ are opposed on a grammatical level, as determined and indetermined, and their grammatical characteristics lead to some semantical differences. Hence, most of the observed differences between gnat’ and gonjat’ are not of a lexical type; they are rather the result of the semantical differences between the determined gnat’ and the indetermined gonjat’. In the part of our thesis dedicated to morphological derivation, our goal was to study the impacts of verbal prefixation and the change of meaning as a result of the prefixation for these verbs. We have studied prefixed verbs based on gnat’ / gonjat’ with spatial meanings, clustering them depending on their spatial orientation: from the starting point, to the point of arrival, both at the same time or in relation to a landmark. A particular focus has been placed on the semantical and aspectual differences of some verbs with prefixes that share the same spatial values. The analysis of verbs with spatial prefixes was done according to the morphology of the aspect: the verbs with prefixes outside aspectual pairs and the pair of verbs. Some particularities have been observed. For the semantic study to be complete, we have added the question of the phrasemes using these verbs. Then, we studied the similarity between gnat’ and gonjat’ in their simple and prefixed forms and the verb of position sidet’: what those verbs have in common but also the limits of their similarities. Finally, we have taken concrete linguistic situations involving gnat’ and gonjat’ in their simple and prefixed forms in order to outline a number of mechanisms leading to an expressive result
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Mallinson, Helen. « The gnat and the vacuum : Robert Boyle and the history of air ». Thesis, Birkbeck (University of London), 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.581441.
Texte intégralRésumé :
The thesis presents an intellectual history of air. It investigates a critical period when the concept of air changed from being an all pervasive 'element' within a predominantly Aristotelian cosmology, to an 'ocean', or a fluid and particulate body with mass and weight. The thesis is set in the context of the seventeenth-century revolution in science in England and is focused on the pneumatic work of Robert Boyle. The question behind the thesis is raised by a specific experiment published by Boyle in 1672 when he describes how he tried, and failed, to produce gnats in a flask that had been evacuated of air by his air-pump. The historical aspect of the thesis examines the development of the vacuum, a new and revolutionary experimental site, in tandem with the equally revolutionary developments in physiology. The philosophical aspect of the thesis examines the conceptual ideas being played out in the Gnat Experiment and the relation between natural philosophy and theology. In terms of its empirical method the experiment was emblematic of the new science being developed by Boyle. The ambition behind the experiment, however, and Boyle's disappointment at its failure, engages another level of enquiry. Of particular interest is the problem of 'thinking matter' and the conflicts it provoked in relation to discussions of air and the vacuum, life and soul. Though reignited by Descartes, the discussion can be traced back to the early theories of air in Presocratic philosophy and the development of the 'pneumatic tradition' through later Socratic and Stoic philosophy, as well as Christian theology, in the guise of pneuma. It becomes apparent that Boyle's 'air' engages a complex field of concepts and arguments that can be traced back to the beginnings of philosophy and science, and that are still burning.
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Nigh, Edward L. Jr, Christopher Sumner et Thomas Svodoba. « An Evaluation of Biological Agents for Control of Citrus Nematode and Liohippelates Eye Gnat ». College of Agriculture, University of Arizona (Tucson, AZ), 1997. http://hdl.handle.net/10150/220522.
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Biological agents have been employed in a series of experiments to evaluate their efftcacy,in control of the citrus nematode and Liohippelates eye gnat in the Yuma mesa area. Steinernema riobravis, an entomopathological nematode, considered climatically adapted to western Arizona temperatures, was selected from commercially available sources. Three field trials and a greenhouse study utilizing the nematodes at population ratés of one and two billion juveniles per acre were each unsuccessful in reducing the nematode or insect pest. Poor viability and survival were attributed to the negative results in each of the investigations. The microbial nematicide, DiTera, which was included in two limited trials, was found to be highly effective in suppression of citrus nematode populations infecting Yuma citrus. These results have prompted Abbott Laboratories, manufactures of the product; to establish two demonstration plots in the Yuma mesa area.
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MONROY, MEJIA MANUEL RODRIGO. « Control de Fungus gnat durante el enraizamiento ex vitro de esquejes de planta de papa ». Tesis de Licenciatura, Universidad Autónoma del Estado de México, 2019. http://hdl.handle.net/20.500.11799/99441.
Texte intégralRésumé :
Con el objetivo de controlar Fungus gnat (Bradysia difformis) durante el enraizamiento ex
vitro de esquejes de plantas de papa (Solanum tuberosum L.) dentro del área de
enraizamiento de la empresa Agrícola Villarreal S.P.R. de R.L., dedicada a la producción
de semilla de papa, se realizó el estudio en el siguiente orden, primero se inició con la
colecta e identificación de ejemplares del insecto plaga, la cual fue identificada como:
Bradysia difformis. En seguida se hicieron diferentes pruebas a diferentes
concentraciones de enraizadores (Hormovit® y Raizal 400®) y sustratos como control
cultural, obteniéndose la mejor calidad de planta con el tratamiento de fibra de coco y 0.1
g.L-1 de Raizal 400®. Después de obtener plantas de calidad se hicieron pruebas con dos
productos amigables con el ambiente: VectoBac® (Bacillus Thurigensis var. Israelensis)
y Azanim® (Azadiractina 3% CE) a diferentes dosis (0.5, 1.0, 2.5 y g.L-1 o mL.L-1, según
el caso) y testigo. El control químico se realizó con una mezcla de tres productos:
HERALD ® (Fenpropatrin), AMBUSH 34® (Permetrina) más TIRANO 200 CE®
(Cipermetrina) a una dosis de 0.5 mL.L-1 de cada uno y, se comparó con VectoBac® a
una dosis de 2.5 g.L-1, que resultó ser el insecticida y la concentración más eficiente en
el control de Fungus gnat. Las aplicaciones de dichos productos se realizaron bajo
invernadero plagado. Se realizaron cuatro aplicaciones, una por semana en aspersión al
igual que los conteos de plantas (% de mortandad y/o sobrevivencia). Una vez realizadas
las pruebas con los insecticidas se aplicó el mejor producto en el área de enraizamiento
de la empresa y finalmente se colocaron trampas para evaluar el índice de población y el
conteo de hembras y machos en el área de enraizamiento de Agricola Villarreal S.P.R.
de R.L., en todas las semanas se obtuvo una relación de 2:1 machos:hembras (66:33
XIII
machos:hembras). Finalmente se erradicó Bradysia difformis en el lugar, con una quinta
aplicación.
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Anas, Osama. « Interactions between Sclerotinia sclerotiorum (Lib.) de Bary, Bradysia coprophila Lintner (dark-winged fungus gnat) and mycoparasitic fungi ». Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=75777.
Texte intégralRésumé :
Sclerotinia sclerotiorum is a pathogen of crops grown in the muck soil regions of Quebec. Soil baiting tests indicated that the sclerotia of S. sclerotiorum are attacked and destroyed by the larvae of Bradysia coprophila and mycoparasites. Sclerotia with rinds partially damaged by the larvae were found to be more susceptible to mycoparasitism by Trichoderma viride. Increasing the organic matter content and porosity of soils resulted in increased damage to sclerotia when larvae were present. Studies conducted to determine if larvae could be reared on diets of various fungi and plant tissue showed that mycelia and sclerotia of S. sclerotiorum were the most successful food sources, followed by mycelia and sclerotia of Botrytis porri and Rhizoctonia solani. Adults produced on mycelia and sclerotia of Sclerotinia minor, Fusarium solani f. sp. pisi, and Botrytis cinerea seldom were fertile. Larvae generally failed to survive when reared on cultures of Trichoderma viride. Larval development occurred on all plants inoculated with the above pathogens but failed to occur on noninoculated healthy plants. Salivary gland secretions of the larvae were found to inhibit the germination of sclerotia. Analyses of the secretion determined that it contains 4.3% protein and had chitinase activity. Mechanically damaged and undamaged sclerotia exhibited an increase in eruptive mycelial germination when treated with 1.5 $ mu$g ml$ sp{-1}$ chitinase but germination decreased at 50, 100 and 150 $ mu$g ml$ sp{-1}$ chitinase concentrations. Noneruptive mycelial germination and carpogenic germination occurred when sclerotia were treated with acetate buffer and distilled water.
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Mochizuki, Ko. « Diversity of plants pollinated by fungus gnats and associated floral syndrome ». Kyoto University, 2018. http://hdl.handle.net/2433/232293.
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Vaughan, Martha Marie. « Molecular and Functional Characterization of Terpene Chemical Defense in Arabidopsis Roots in Interaction with the Herbivore Bradysia spp. (fungus gnat) ». Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/77974.
Texte intégralRésumé :
Roots and leaves are integrated structural elements that together sustain plant growth and development. Insect herbivores pose a constant threat to both above- and belowground plant tissues. To ward off herbivorous insects, plants have developed different strategies such as direct and indirect chemical defense mechanisms. Research has primarily focused on visible aboveground interactions between plants and herbivores. Root-feeding insects, although often overlooked, play a major role in inducing physical and physiological changes in plants. However, little is known about how plants deploy chemical defense against root herbivores.
We have developed an Arabidopsis aeroponic culture system based on clay granulate, which provides access to root tissue and accommodates subterranean insect herbivores. Using this system, feeding performance and plant tissue damage by the root herbivore Bradysia (fungus gnat) were evaluated. Larval feeding was found to reduce Arabidopsis root biomass and water uptake.
Furthermore, we have characterized a root-specific terpene synthase AtTPS08, which is responsible for the constitutive formation of the novel volatile diterpene compound, rhizathalene, in Arabidopsis roots. Rhizathalene synthase is a class I diterpene synthase that has high affinity for the substrate geranylgeranyl diphosphate (GGPP) and is targeted to the root leucoplast. Expression of the β-glucuronidase (GUS) reporter gene fused to the upstream genomic region of AtTPS08 demonstrated constitutive promoter activity in the root vascular tissue and root tips. Using the established bioassay with Arabidopsis and Bradysia larvae, in aeroponic culture we could show that roots deficient in rhizathalene synthesis were more susceptible to herbivory. Our work provides in vivo-evidence that diterpene compounds are involved in belowground direct defense against root-feeding insects.
Future work is still required to improve our understanding of plant root defense. This study has provided a basis for future investigations on the biochemistry, molecular regulation and defensive function of Arabidopsis root chemicals in interaction with both above- and belowground herbivores (and pathogens).Ph. D.
Livres sur le sujet "GNPAT"
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Benedict, Kitty. Gnat. Mankato, MN, USA : Creative Education, 1993.
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Jim, Minter, dir. Life on the gnat line. Marietta : SpeakingDirect Publishing, 2010.
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Virgil. The gnat and other minor poems of Virgil. Berkeley : University of California Press, 2011.
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Gnat Stokes and the Foggy Bottom Swamp Queen. New York : Philomel Books, 2005.
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Stone, Christopher D. The gnat is older than man : Global environment andhuman agenda. Princeton, N.J : Princeton University Press, 1993.
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Teachers, Ghana National Association of. GNAT, our diamond jubilee : 60 years, 1931-1991 : souvenir brochure. Accra : Ghana National Association of Teachers, 1994.
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Stone, Christopher D. The gnat is older than man : Global environment and human agenda. Princeton, N.J : Princeton University Press, 1993.
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Rutstein, Nathan. From a gnat to an eagle : The story of Nathan Rutstein. Wilmette, Ill : Bahá'í Pub., 2008.
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Ghana National Association of Teachers. Constitution and rules of the Ghana National Association of Teachers (GNAT). Accra : General Secretary, GNAT, 1987.
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Stone, Christopher D. The gnat is older than man : Global environment and human agenda. Princeton, NJ : Princeton University Press, 1995.
Trouver le texte intégralChapitres de livres sur le sujet "GNPAT"
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Peck, Stewart B., Carol C. Mapes, Netta Dorchin, John B. Heppner, Eileen A. Buss, Gustavo Moya-Raygoza, Marjorie A. Hoy et al. « Gnat Bugs ». Dans Encyclopedia of Entomology, 1630. Dordrecht : Springer Netherlands, 2008. http://dx.doi.org/10.1007/978-1-4020-6359-6_1126.
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Plake, Conrad. « Gene Normalization with GNAT ». Dans Encyclopedia of Systems Biology, 796–97. New York, NY : Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4419-9863-7_147.
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Erdmann, Michael. « GNAT Ada Database Development Environment ». Dans Lecture Notes in Computer Science, 334–43. Berlin, Heidelberg : Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/3-540-48046-3_26.
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Rybin, Sergey, Alfred Strohmeier, Vasiliy Fofanov et Alexei Kuchumov. « ASIS-for-GNAT : A Report of Practical Experiences ». Dans Reliable Software Technologies Ada-Europe 2000, 125–37. Berlin, Heidelberg : Springer Berlin Heidelberg, 2000. http://dx.doi.org/10.1007/10722060_13.
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de la Puente, Juan A., José F. Ruiz et Juan Zamorano. « An Open Ravenscar Real-Time Kernel for GNAT ». Dans Reliable Software Technologies Ada-Europe 2000, 5–15. Berlin, Heidelberg : Springer Berlin Heidelberg, 2000. http://dx.doi.org/10.1007/10722060_4.
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Rybin, Sergey, Alfred Strohmeier et Eugene Zueff. « ASIS for GNAT : Goals, problems and implementation strategy ». Dans Ada in Europe, 139–51. Berlin, Heidelberg : Springer Berlin Heidelberg, 1996. http://dx.doi.org/10.1007/bfb0015489.
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Crawford, David L., Eric R. Craine et Roy A. Tucker. « GNAT—A Global Network of Small Astronomical Telescopes ». Dans Astrophysics and Space Science Library, 189–200. Dordrecht : Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-010-0253-0_17.
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Miranda, Javier, et Edmond Schonberg. « Abstract Interface Types in GNAT : Conversions, Discriminants, and C++ ». Dans Reliable Software Technologies – Ada-Europe 2006, 179–90. Berlin, Heidelberg : Springer Berlin Heidelberg, 2006. http://dx.doi.org/10.1007/11767077_15.
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Ruiz, José F. « GNAT Pro for On-board Mission-Critical Space Applications ». Dans Reliable Software Technology – Ada-Europe 2005, 248–59. Berlin, Heidelberg : Springer Berlin Heidelberg, 2005. http://dx.doi.org/10.1007/11499909_20.
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Blieberger, Johann, et Bernd Burgstaller. « Eliminating Redundant Range Checks in GNAT Using Symbolic Evaluation ». Dans Lecture Notes in Computer Science, 153–67. Berlin, Heidelberg : Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/3-540-44947-7_11.
Texte intégralActes de conférences sur le sujet "GNPAT"
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Miranda, Javier, et Edmond Schonberg. « GNAT ». Dans the 2004 annual ACM SIGAda international conference. New York, New York, USA : ACM Press, 2004. http://dx.doi.org/10.1145/1032297.1032307.
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Gicca, Greg, et Ben Brosgol. « GNAT BoF ». Dans the 2008 ACM annual international conference. New York, New York, USA : ACM Press, 2008. http://dx.doi.org/10.1145/1454474.1454496.
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Schonberg, Edmond, et Bernard Banner. « The GNAT project ». Dans the conference. New York, New York, USA : ACM Press, 1994. http://dx.doi.org/10.1145/197694.197706.
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Dewar, Robert. « The GNAT compilation model ». Dans the conference. New York, New York, USA : ACM Press, 1994. http://dx.doi.org/10.1145/197694.197708.
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Kenner, Richard. « Integrating GNAT and GCC ». Dans the conference. New York, New York, USA : ACM Press, 1994. http://dx.doi.org/10.1145/197694.197710.
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de la Puente, Juan A., José F. Ruiz et Jesús M. González-Barahona. « Real-time programming with GNAT ». Dans the ninth international workshop. New York, New York, USA : ACM Press, 1999. http://dx.doi.org/10.1145/329607.334742.
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Kermarrec, Yvon, Laurent Nana et Laurent Pautet. « Implementing recovery blocks in GNAT ». Dans the conference. New York, New York, USA : ACM Press, 1995. http://dx.doi.org/10.1145/376503.376722.
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Crawford, David L., et Eric R. Craine. « Global network of astronomical telescopes : GNAT ». Dans 1994 Symposium on Astronomical Telescopes & Instrumentation for the 21st Century, sous la direction de David L. Crawford et Eric R. Craine. SPIE, 1994. http://dx.doi.org/10.1117/12.176714.
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Comar, Cyrille, Gary Dismukes et Franco Gasperoni. « The GNAT implementation of controlled types ». Dans the conference. New York, New York, USA : ACM Press, 1995. http://dx.doi.org/10.1145/376503.376724.
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Gasperoni, Franco, et Patrick Bazire. « Smart recompilation and the GNAT compiler ». Dans the conference. New York, New York, USA : ACM Press, 1994. http://dx.doi.org/10.1145/197694.197712.
Texte intégralRapports d'organisations sur le sujet "GNPAT"
1
Peer, C. F. NATO SEA GNAT Program. Fort Belvoir, VA : Defense Technical Information Center, mars 1985. http://dx.doi.org/10.21236/ada153868.
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2
Gehrke, R. J., R. Aryaeinejad, K. D. Watts, D. R. Staples et D. W. Akers. Application of PINS and GNAT to the assay of 55-gal containers of radioactive waste. Office of Scientific and Technical Information (OSTI), mars 1994. http://dx.doi.org/10.2172/10167553.
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