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1.
Mol Cytogenet ; 15(1): 16, 2022 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-35366924

RESUMO

BACKGROUND: Noninvasive prenatal testing (NIPT) is the most recent modality widely used in prenatal diagnostics. Commercially available NIPT has high sensitivity and specificity for the common fetal chromosomal aneuploidies. As future advancements in NIPT sequencing technology are becoming promising and more reliable, the ability to detect beyond aneuploidies and to expand detection of submicroscopic genomic alterations, as well as single-gene disorders might become possible. CASE PRESENTATION: Here we present a case of a 34-year-old pregnant woman, G2P1, who had NIPT screening which detected a terminal microduplication of 10.34 Mb on the long arm of chromosome 15 (15q26.1q26.3). Subsequent prenatal diagnostic testing including karyotype, microarray and fluorescence in situ hybridization (FISH) analyses were performed. Microarray testing confirmed and particularized a copy number gain of 10.66 Mb of the distal end of the long arm of chromosome 15. The G-banding cytogenetic studies yielded results consistent with unbalanced translocation between chromosome 15 and 18. To further characterize the abnormality involving the long arm of chromosome 18 and to map the genomic location of the duplicated 15q more precisely, FISH analysis using specific sub-telomeric probes was performed. FISH analysis confirmed that the extra duplicated segment of chromosome 15 is translocated onto the distal end of the long arm of chromosome 18 at band 18q23. Parental karyotype and FISH studies were performed to see if this unbalanced rearrangement was inherited from a healthy balanced translocation carrier versus being a de novo finding. Parental chromosomal analysis provided no evidence of a rearrangement between chromosome 15 and chromosome 18. The final fetal karyotype was reported as 46,XX,der(18)t(15;18)(q26.2;q23)dn. CONCLUSIONS: In this case study, the microduplication of fetal chromosome 15q26.1q26.3 was accurately detected using NIPT. Our results suggest that further refinements in NIPT have the potential to evolve to a powerful and efficient screening method, which might be used to detect a broad range of chromosomal imbalances. Since microduplications and microdeletions are a potential reportable result with NIPT, this must be included in pre-test counseling. Prenatal diagnostic testing of such findings is strongly recommended.

3.
Antioxidants (Basel) ; 9(9)2020 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-32858836

RESUMO

Plants are a reservoir of high-value molecules with underexplored biomedical applications. With the aim of identifying novel health-promoting attributes in underexplored natural sources, we scrutinized the diversity of (poly)phenols present within the berries of selected germplasm from cultivated, wild, and underutilized Rubus species. Our strategy combined the application of metabolomics, statistical analysis, and evaluation of (poly)phenols' bioactivity using a yeast-based discovery platform. We identified species as sources of (poly)phenols interfering with pathological processes associated with redox-related diseases, particularly, amyotrophic lateral sclerosis, cancer, and inflammation. In silico prediction of putative bioactives suggested cyanidin-hexoside as an anti-inflammatory molecule which was validated in yeast and mammalian cells. Moreover, cellular assays revealed that the cyanidin moiety was responsible for the anti-inflammatory properties of cyanidin-hexoside. Our findings unveiled novel (poly)phenolic bioactivities and illustrated the power of our integrative approach for the identification of dietary (poly)phenols with potential biomedical applications.

4.
BMC Genomics ; 20(1): 995, 2019 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-31856735

RESUMO

BACKGROUND: Flavonoids are produced in all flowering plants in a wide range of tissues including in berry fruits. These compounds are of considerable interest for their biological activities, health benefits and potential pharmacological applications. However, transcriptomic and genomic resources for wild and cultivated berry fruit species are often limited, despite their value in underpinning the in-depth study of metabolic pathways, fruit ripening as well as in the identification of genotypes rich in bioactive compounds. RESULTS: To access the genetic diversity of wild and cultivated berry fruit species that accumulate high levels of phenolic compounds in their fleshy berry(-like) fruits, we selected 13 species from Europe, South America and Asia representing eight genera, seven families and seven orders within three clades of the kingdom Plantae. RNA from either ripe fruits (ten species) or three ripening stages (two species) as well as leaf RNA (one species) were used to construct, assemble and analyse de novo transcriptomes. The transcriptome sequences are deposited in the BacHBerryGEN database (http://jicbio.nbi.ac.uk/berries) and were used, as a proof of concept, via its BLAST portal (http://jicbio.nbi.ac.uk/berries/blast.html) to identify candidate genes involved in the biosynthesis of phenylpropanoid compounds. Genes encoding regulatory proteins of the anthocyanin biosynthetic pathway (MYB and basic helix-loop-helix (bHLH) transcription factors and WD40 repeat proteins) were isolated using the transcriptomic resources of wild blackberry (Rubus genevieri) and cultivated red raspberry (Rubus idaeus cv. Prestige) and were shown to activate anthocyanin synthesis in Nicotiana benthamiana. Expression patterns of candidate flavonoid gene transcripts were also studied across three fruit developmental stages via the BacHBerryEXP gene expression browser (http://www.bachberryexp.com) in R. genevieri and R. idaeus cv. Prestige. CONCLUSIONS: We report a transcriptome resource that includes data for a wide range of berry(-like) fruit species that has been developed for gene identification and functional analysis to assist in berry fruit improvement. These resources will enable investigations of metabolic processes in berries beyond the phenylpropanoid biosynthetic pathway analysed in this study. The RNA-seq data will be useful for studies of berry fruit development and to select wild plant species useful for plant breeding purposes.


Assuntos
Flavonoides/biossíntese , Frutas/genética , Genes de Plantas , Rubus/genética , Transcriptoma , Antocianinas/biossíntese , Vias Biossintéticas/genética , Frutas/crescimento & desenvolvimento , Frutas/metabolismo , Magnoliopsida/classificação , Magnoliopsida/genética , Fenóis/análise , Filogenia , Proteínas de Plantas/genética , RNA-Seq , Rubus/química , Rubus/crescimento & desenvolvimento , Rubus/metabolismo
5.
Metabolomics ; 15(1): 12, 2019 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-30830439

RESUMO

INTRODUCTION: Blackcurrant (Ribes nigrum L.) is an excellent example of a "super fruit" with potential health benefits. Both genotype and cultivation environment are known to affect the chemical composition of blackcurrant, especially ascorbic acid and various phenolic compounds. Environmental conditions, like temperature, solar radiation and precipitation can also have significant impact on fruit chemical composition. The relevance of the study is further accentuated by the predicted and ongoing changes in global climate. OBJECTIVES: The aim of the present study was to provide new knowledge and a deeper understanding of the effects of post flowering environmental conditions, namely temperature and day length, on fruit quality and chemical composition of blackcurrant using an untargeted high performance liquid chromatography-photo diode array-mass spectrometry (HPLC-PDA-MS) metabolomics approach. METHODS: A phytotron experiment with cultivation of single-stemmed potted plants of blackcurrant cv. Narve Viking was conducted using constant temperatures of 12, 18 or 24 °C and three different photoperiods (short day, short day with night interruption, and natural summer daylight conditions). Plants were also grown under ambient outdoor conditions. Ripe berries were analysed using an untargeted HPLC-PDA-MS metabolomics approach to detect the presence and concentration of molecules as affected by controlled climatic factors. RESULTS: The untargeted metabolomics dataset contained a total of 7274 deconvolved retention time-m/z pairs across both electrospray ionisation (ESI) positive and negative polarities, from which 549 metabolites were identified or minimally annotated based upon accurate mass MS. Conventional principal component analysis (PCA) in combination with the Friedman significance test were applied to first identify which metabolites responded to temperature in a linear fashion. Multi-block hierarchical PCA in combination with the Friedman significance test was secondly applied to identify metabolites that were responsive to different day length conditions. Temperature had significant effect on a total of 365 metabolites representing a diverse range of chemical classes. It was observed that ripening of the blackcurrant berries under ambient conditions, compared to controlled conditions, resulted in an increased accumulation of 34 annotated metabolites, mainly anthocyanins and flavonoids. 18 metabolites were found to be regulated differentially under the different daylength conditions. Moreover, based upon the most abundant anthocyanins, a comparison between targeted and untargeted analyses, revealed a close convergence of the two analytical methods. Therefore, the study not just illustrates the value of non-targeted metabolomics approaches with respect to the huge diversity and numbers of significantly changed metabolites detected (and which would be missed by conventional targeted analyses), but also shows the validity of the non-targeted approach with respect to its precision compared to targeted analyses. CONCLUSIONS: Blackcurrant maturation under controlled ambient conditions revealed a number of insightful relationships between environment and chemical composition of the fruit. A prominent reduction of the most abundant anthocyanins under the highest temperature treatments indicated that blackcurrant berries in general may accumulate lower total anthocyanins in years with extreme hot summer conditions. HPLC-PDA-MS metabolomics is an excellent method for broad analysis of chemical composition of berries rich in phenolic compounds. Moreover, the experiment in controlled phytotron conditions provided additional knowledge concerning plant interactions with the environment.


Assuntos
Ribes/crescimento & desenvolvimento , Ribes/metabolismo , Cromatografia Líquida de Alta Pressão/métodos , Ritmo Circadiano/fisiologia , Flavonoides/metabolismo , Frutas/química , Frutas/genética , Frutas/metabolismo , Interação Gene-Ambiente , Metabolômica/métodos , Fenóis/metabolismo , Ribes/genética , Espectrometria de Massas por Ionização por Electrospray/métodos , Temperatura
6.
J Agric Food Chem ; 66(4): 831-841, 2018 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-29257861

RESUMO

The reduction of the environmental footprint of crop production without compromising crop yield and their nutritional value is a key goal for improving the sustainability of agriculture. In 2009, the Balruddery Farm Platform was established at The James Hutton Institute as a long-term experimental platform for cross-disciplinary research of crops using two agricultural ecosystems. Crops representative of UK agriculture were grown under conventional and integrated management systems and analyzed for their water-soluble vitamin content. Integrated management, when compared with the conventional system, had only minor effects on water-soluble vitamin content, where significantly higher differences were seen for the conventional management practice on the levels of thiamine in field beans (p < 0.01), Spring barley (p < 0.05), and Winter wheat (p < 0.05), and for nicotinic acid in Spring barley (p < 0.05). However, for all crops, variety and year differences were of greater importance. These results indicate that the integrated management system described in this study does not significantly affect the water-soluble vitamin content of the crops analyzed here.


Assuntos
Agricultura/métodos , Produtos Agrícolas/química , Grão Comestível/química , Solanum tuberosum/química , Vicia faba/química , Vitaminas/análise , Ácido Ascórbico/análise , Hordeum/química , Niacina/análise , Valor Nutritivo , Estações do Ano , Tiamina/análise , Triticum/química , Reino Unido , Complexo Vitamínico B/análise
7.
Front Plant Sci ; 7: 1263, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27610114

RESUMO

Solanesol is a high value 45-carbon, unsaturated, all-trans-nonaprenol isoprenoid. Recently solanesol has received particular attention because of its utility, both in its own right and as a precursor in the production of numerous compounds used in the treatment of disease states. Solanesol is found mainly in solanaceous crops such as potato, tomato, tobacco and pepper where it accumulates in the foliage. There is considerable potential to explore the extraction of solanesol from these sources as a valuable co-product. In this study we have characterized the genetic variation in leaf solanesol content in a biparental, segregating diploid potato population. We demonstrate that potato leaf solanesol content is genetically controlled and identify several quantitative trait loci associated with leaf solanesol content. Transient over-expression of genes from the methylerythritol 4-phosphate (MEP) and mevalonic acid (MVA) pathways, either singly or in combination, resulted in enhanced accumulation of solanesol in leaves of Nicotiana benthamiana, providing insights for genetically engineering the pathway. We also demonstrate that in potato, leaf solanesol content is enhanced by up to six-fold on exposure to moderately elevated temperature and show corresponding changes in expression patterns of MEP and MVA genes. Our combined approaches offer new insights into solanesol accumulation and strategies for developing a bio-refinery approach to potato production.

8.
Nucleus ; 6(1): 66-76, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25738644

RESUMO

More than 20 mutations in the gene encoding A-type lamins (LMNA) cause progeria, a rare premature aging disorder. The major pathognomonic hallmarks of progeria cells are seen as nuclear deformations or blebs that are related to the redistribution of A- and B-type lamins within the nuclear lamina. However, the functional significance of these progeria-associated blebs remains unknown. We have carried out an analysis of the structural and functional consequences of progeria-associated nuclear blebs in dermal fibroblasts from a progeria patient carrying a rare point mutation p.S143F (C428T) in lamin A/C. These blebs form microdomains that are devoid of major structural components of the nuclear envelope (NE)/lamina including B-type lamins and nuclear pore complexes (NPCs) and are enriched in A-type lamins. Using laser capture microdissection and comparative genomic hybridization (CGH) analyses, we show that, while these domains are devoid of centromeric heterochromatin and gene-poor regions of chromosomes, they are enriched in gene-rich chromosomal regions. The active form of RNA polymerase II is also greatly enriched in blebs as well as nascent RNA but the nuclear co-activator SKIP is significantly reduced in blebs compared to other transcription factors. Our results suggest that the p.S143F progeria mutation has a severe impact not only on the structure of the lamina but also on the organization of interphase chromatin domains and transcription. These structural defects are likely to contribute to gene expression changes reported in progeria and other types of laminopathies.


Assuntos
Núcleo Celular/genética , Cromossomos Humanos/genética , Lamina Tipo B/deficiência , Progéria/genética , Progéria/patologia , Núcleo Celular/metabolismo , Criança , Feminino , Humanos , Lamina Tipo B/genética , Mutação , Transcrição Gênica
9.
Sci Transl Med ; 6(247): 247ra101, 2014 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-25080476

RESUMO

Glioblastoma multiforme (GBM) is the most frequent and aggressive brain tumor in adults. The dogma that GBM spread is restricted to the brain was challenged by reports on extracranial metastases after organ transplantation from GBM donors. We identified circulating tumor cells (CTCs) in peripheral blood (PB) from 29 of 141 (20.6%) GBM patients by immunostaining of enriched mononuclear cells with antibodies directed against glial fibrillary acidic protein (GFAP). Tumor cell spread was not significantly enhanced by surgical intervention. The tumor nature of GFAP-positive cells was supported by the absence of those cells in healthy volunteers and the presence of tumor-specific aberrations such as EGFR gene amplification and gains and losses in genomic regions of chromosomes 7 and 10. Release of CTCs was associated with EGFR gene amplification, suggesting a growth potential of these cells. We demonstrate that hematogenous GBM spread is an intrinsic feature of GBM biology.


Assuntos
Neoplasias Encefálicas/patologia , Glioblastoma/secundário , Células Neoplásicas Circulantes/patologia , Biomarcadores Tumorais/análise , Biomarcadores Tumorais/genética , Neoplasias Encefálicas/química , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/cirurgia , Estudos de Casos e Controles , Linhagem Celular Tumoral , Cromossomos Humanos Par 10 , Cromossomos Humanos Par 7 , Hibridização Genômica Comparativa , Receptores ErbB/genética , Feminino , Amplificação de Genes , Proteína Glial Fibrilar Ácida/análise , Glioblastoma/química , Glioblastoma/genética , Glioblastoma/cirurgia , Humanos , Imuno-Histoquímica , Hibridização in Situ Fluorescente , Masculino , Pessoa de Meia-Idade , Células Neoplásicas Circulantes/química
10.
Prenat Diagn ; 34(2): 185-91, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24222400

RESUMO

OBJECTIVE: The objective of this study is to validate the diagnostic accuracy of a non-invasive prenatal test for detecting trisomies 13, 18, and 21 for a population in Germany and Switzerland. METHODS: Random massively parallel sequencing was applied using Illumina sequencing platform HiSeq2000. Fetal aneuploidies were identified using a median absolute deviation based z-score equation. A bioinformatics algorithm based on guanine-cytosine normalization was applied after the data were unblinded. Results of massively parallel sequencing and invasive procedures were compared. RESULTS: Overall, 40/42 samples were correctly classified as trisomy 21-positive, including a translocation trisomy 21 [46,XY,der(13;21),+21] and a structural aberration of chromosome 21 [46,XX,rec(21)dup(21q)inv(21)(p12q21.1)] but not including a low percentage mosaic trisomy 21 [47,XY,+21/46,XY], [sensitivity: 95.2%; one-sided lower confidence limit: 85.8%]; 430/430 samples were correctly classified as trisomy 21-negative (specificity: 100%; one-sided lower CL: 99.3%). Using a new bioinformatics algorithm with guanine-cytosine normalization, detection of trisomy 21 was facilitated, and five of five trisomy 13 cases and eight of eight trisomy 18 cases were correctly identified. CONCLUSION: Our newly established non-invasive prenatal test allows detection of fetal trisomies 13, 18, and 21 with high accuracy in a population in Germany and Switzerland.


Assuntos
Transtornos Cromossômicos/diagnóstico , Síndrome de Down/diagnóstico , Sequenciamento de Nucleotídeos em Larga Escala , Diagnóstico Pré-Natal , Análise de Sequência de DNA , Trissomia/diagnóstico , Adulto , Algoritmos , Amniocentese , Aneuploidia , Amostra da Vilosidade Coriônica , Aberrações Cromossômicas , Transtornos Cromossômicos/genética , Cromossomos Humanos Par 13/genética , Cromossomos Humanos Par 18/genética , Síndrome de Down/genética , Feminino , Alemanha , Humanos , Cariotipagem , Masculino , Pessoa de Meia-Idade , Mosaicismo , Gravidez , Sensibilidade e Especificidade , Suíça , Trissomia/genética , Síndrome da Trissomia do Cromossomo 13 , Síndrome da Trissomía do Cromossomo 18 , Adulto Jovem
11.
Environ Sci Process Impacts ; 15(2): 463-9, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25208711

RESUMO

FePO4 based molluscicides (snail pellets) also contain a chelating agent. The influence of the chelating agent, which is intrinsically present in the molluscicide, on the phytoavailability of other metals present in the growth medium was investigated in the present study. Cucumber plants (Cucumis sativus) were grown in a hydroponic nutrient solution and exposed for one week to different metals in combination with a chelating agent containing molluscicide. Oven dried roots and shoots of plants were HNO 3/H2O2 microwave digested and analysed regarding total Fe, stable isotopic (54)Fe, Cd, Pb, and Bi concentrations using ICP-MS. The results showed that the addition of a chelating agent enhances the Fe phytoavailability to the plant, whether as an intrinsic part of the molluscicide or added individually. Additionally, the chelating agent present in the pesticide mobilises externally added metals and thus increases their phytoavailability. In particular the significantly higher Cd concentration in shoots from plants exposed to chelating agents indicates a potentially detrimental environmental effect.


Assuntos
Cucumis sativus/efeitos dos fármacos , Metais/análise , Moluscocidas/toxicidade , Poluentes do Solo/toxicidade , Animais , Cucumis sativus/fisiologia , Caramujos , Poluentes do Solo/análise
12.
Clin Chem ; 59(1): 252-60, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23136247

RESUMO

BACKGROUND: Molecular characterization of circulating tumor cells (CTCs) is pivotal to increasing the diagnostic specificity of CTC assays and investigating therapeutic targets and their downstream pathways on CTCs. We focused on epidermal growth factor receptor (EGFR) and genes relevant for its inhibition in patients with colorectal cancer (CRC). METHODS: We used the CellSearch® system for CTC detection in peripheral blood samples from 49 patients with metastatic CRC (mCRC) and 32 patients with nonmetastatic CRC (nmCRC). We assessed EGFR expression in 741 CTCs from 27 patients with mCRC and 6 patients with nmCRC using a fluorescein-conjugated antibody with the CellSearch Epithelial Cell Kit. DNA of a single CTC isolated by micromanipulation was propagated by whole-genome amplification and analyzed by quantitative PCR for EGFR gene amplification and sequencing for KRAS (v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog), BRAF (v-raf murine sarcoma viral oncogene homolog B1), and PIK3CA (phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit α) mutations. RESULTS: At least 2 CTCs were detected in 24 of 49 patients with mCRC and 7 of 32 patients with nmCRC. In 7 of 33 patients, CTCs with increased EGFR expression were identified. Heterogeneity in EGFR expression was observed between CTCs from the same patient. EGFR gene amplification was found in 7 of 26 CTCs from 3 patients. The investigated BRAF gene locus was not mutated in 44 analyzed CTCs, whereas KRAS mutations were detected in 5 of 15 CTCs from 1 patient and PIK3CA mutations in 14 of 36 CTCs from 4 patients. CONCLUSIONS: Molecular characterization of single CTCs demonstrated considerable intra- and interpatient heterogeneity of EGFR expression and genetic alterations in EGFR, KRAS, and PIK3CA, possibly explaining the variable response rates to EGFR inhibition in patients with CRC.


Assuntos
Neoplasias Colorretais/sangue , Receptores ErbB/sangue , Genes ras , Mutação , Células Neoplásicas Circulantes , Fosfatidilinositol 3-Quinases/genética , Classe I de Fosfatidilinositol 3-Quinases , Neoplasias Colorretais/genética , Humanos , Fosfatidilinositol 3-Quinases/sangue , Proteínas Proto-Oncogênicas B-raf/genética , Reação em Cadeia da Polimerase em Tempo Real , Transdução de Sinais
13.
Physiol Plant ; 146(2): 160-72, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22324764

RESUMO

The heathland lichen Cladonia portentosa was collected from sites in mainland Britain differing either in rates of wet N deposition or in annual mean N concentration in rainfall based on a modelled data set. Methanolic extracts of thalli were analyzed by liquid chromatography time-of-flight mass spectrometry to yield metabolic profiles. Differences between sites in metabolite concentration were quantified using multivariate statistical tools and used to identify potential biomarker molecules. The abundances of three structurally related betaine lipids showed an increase with increasing modelled N deposition to a threshold of 22.3 kg ha(-1) year(-1) after which they remained constant. In contrast, the abundance of a phosphatidylcholine (PC) lipid showed concomitant decrease. Correlations of the identified biomarkers with N deposition and precipitation were stronger than those with N concentrations. The results presented in this study clearly show that N enrichment associated with tissue P limitation changes lipid composition, leading to shifts from PCs to betaine lipids, and that these lipids identified have the potential to be used as biomarkers for nitrogen enrichment.


Assuntos
Betaína/metabolismo , Monitoramento Ambiental/métodos , Líquens/metabolismo , Lipotrópicos/metabolismo , Nitrogênio/metabolismo , Fósforo/metabolismo , Atmosfera/química , Biomarcadores/metabolismo , Líquens/química , Metabolismo dos Lipídeos , Estrutura Molecular , Nitrogênio/análise , Fosfatidilcolinas/metabolismo , Chuva/química , Reino Unido
14.
Physiol Plant ; 143(2): 107-14, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21569037

RESUMO

Nitrogen availability has profound ecological consequences in nutrient-limited systems. In terrestrial settings these would include the upland heaths, sand dunes and blanket bogs of temperate latitudes. Understanding the physiological consequences of nitrogen enrichment is a first critical step in predicting possible consequences. Results are presented from a metabolic fingerprinting study using Fourier transform-infrared spectroscopy (FTIR) to detect biochemical differences in the lichen Cladonia portentosa collected from 25 sites across mainland Britain varying in their nitrogen input. Partial least-squares regression analysis of the FTIR data demonstrated that changes in broad biochemical classes were consistently correlated with mean annual wet inorganic nitrogen deposition loads. These results demonstrated a direct coupling of a broad range of metabolic processes in C. portentosa to nitrogen deposition.


Assuntos
Líquens/metabolismo , Metaboloma , Nitrogênio/metabolismo , Algoritmos , Aminoácidos/metabolismo , Atmosfera/química , Polissacarídeos/metabolismo , Proteínas/metabolismo , Chuva/química , Análise de Regressão , Espectroscopia de Infravermelho com Transformada de Fourier , Reino Unido
15.
Biochem J ; 413(1): 115-24, 2008 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-18402553

RESUMO

PtdIns is an important precursor for inositol-containing lipids, including polyphosphoinositides, which have multiple essential functions in eukaryotic cells. It was previously proposed that different regulatory functions of inositol-containing lipids may be performed by independent lipid pools; however, it remains unclear how such subcellular pools are established and maintained. In the present paper, a previously uncharacterized Arabidopsis gene product with similarity to the known Arabidopsis PIS (PtdIns synthase), PIS1, is shown to be an active enzyme, PIS2, capable of producing PtdIns in vitro. PIS1 and PIS2 diverged slightly in substrate preferences for CDP-DAG [cytidinediphospho-DAG (diacylglycerol)] species differing in fatty acid composition, PIS2 preferring unsaturated substrates in vitro. Transient expression of fluorescently tagged PIS1 or PIS2 in onion epidermal cells indicates localization of both enzymes in the ER (endoplasmic reticulum) and, possibly, Golgi, as was reported previously for fungal and mammalian homologues. Constitutive ectopic overexpression of PIS1 or PIS2 in Arabidopsis plants resulted in elevated levels of PtdIns in leaves. PIS2-overexpressors additionally exhibited significantly elevated levels of PtdIns(4)P and PtdIns(4,5)P(2), whereas polyphosphoinositides were not elevated in plants overexpressing PIS1. In contrast, PIS1-overexpressors contained significantly elevated levels of DAG and PtdEtn (phosphatidylethanolamine), an effect not observed in plants overexpressing PIS2. Biochemical analysis of transgenic plants with regards to fatty acids associated with relevant lipids indicates that lipids increasing with PIS1 overexpression were enriched in saturated or monounsaturated fatty acids, whereas lipids increasing with PIS2 overexpression, including polyphosphoinositides, contained more unsaturated fatty acids. The results indicate that PtdIns populations originating from different PIS isoforms may enter alternative routes of metabolic conversion, possibly based on specificity and immediate metabolic context of the biosynthetic enzymes.


Assuntos
Arabidopsis/enzimologia , CDP-Diacilglicerol-Inositol 3-Fosfatidiltransferase/metabolismo , Fosfatidilinositóis/metabolismo , Sequência de Aminoácidos , Arabidopsis/genética , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , CDP-Diacilglicerol-Inositol 3-Fosfatidiltransferase/química , CDP-Diacilglicerol-Inositol 3-Fosfatidiltransferase/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Isoenzimas , Dados de Sequência Molecular , Plantas Geneticamente Modificadas
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