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991.
Background
Genetic interactions between phytohormones in the control of flowering time in Arabidopsis thaliana have not been extensively studied. Three phytohormones have been individually connected to the floral-timing program. The inductive function of gibberellins (GAs) is the most documented. Abscisic acid (ABA) has been demonstrated to delay flowering. Finally, the promotive role of brassinosteroids (BRs) has been established. It has been reported that for many physiological processes, hormone pathways interact to ensure an appropriate biological response.Methodology
We tested possible genetic interactions between GA-, ABA-, and BR-dependent pathways in the control of the transition to flowering. For this, single and double mutants deficient in the biosynthesis of GAs, ABA, and BRs were used to assess the effect of hormone deficiency on the timing of floral transition. Also, plants that over-express genes encoding rate-limiting enzymes in each biosynthetic pathway were generated and the flowering time of these lines was investigated.Conclusions
Loss-of-function studies revealed a complex relationship between GAs and ABA, and between ABA and BRs, and suggested a cross-regulatory relation between GAs to BRs. Gain-of-function studies revealed that GAs were clearly limiting in their sufficiency of action, whereas increases in BRs and ABA led to a more modest phenotypic effect on floral timing. We conclude from our genetic tests that the effects of GA, ABA, and BR on timing of floral induction are only in partially coordinated action. 相似文献992.
Whitaker HC Kote-Jarai Z Ross-Adams H Warren AY Burge J George A Bancroft E Jhavar S Leongamornlert D Tymrakiewicz M Saunders E Page E Mitra A Mitchell G Lindeman GJ Evans DG Blanco I Mercer C Rubinstein WS Clowes V Douglas F Hodgson S Walker L Donaldson A Izatt L Dorkins H Male A Tucker K Stapleton A Lam J Kirk J Lilja H Easton D;IMPACT Study Steering Committee;IMPACT Study Collaborators;UK GPCS Collaborators Cooper C Eeles R Neal DE 《PloS one》2010,5(10):e13363
Background
Microseminoprotein-beta (MSMB) regulates apoptosis and using genome-wide association studies the rs10993994 single nucleotide polymorphism in the MSMB promoter has been linked to an increased risk of developing prostate cancer. The promoter location of the risk allele, and its ability to reduce promoter activity, suggested that the rs10993994 risk allele could result in lowered MSMB in benign tissue leading to increased prostate cancer risk.Methodology/Principal Findings
MSMB expression in benign and malignant prostate tissue was examined using immunohistochemistry and compared with the rs10993994 genotype. Urinary MSMB concentrations were determined by ELISA and correlated with urinary PSA, the presence or absence of cancer, rs10993994 genotype and age of onset. MSMB levels in prostate tissue and urine were greatly reduced with tumourigenesis. Urinary MSMB was better than urinary PSA at differentiating men with prostate cancer at all Gleason grades. The high risk allele was associated with heterogeneity of MSMB staining and loss of MSMB in both tissue and urine in benign prostate.Conclusions
These data show that some high risk alleles discovered using genome-wide association studies produce phenotypic effects with potential clinical utility. We provide the first link between a low penetrance polymorphism for prostate cancer and a potential test in human tissue and bodily fluids. There is potential to develop tissue and urinary MSMB for a biomarker of prostate cancer risk, diagnosis and disease monitoring. 相似文献993.
Uptake of aggregating transthyretin by fat body in a Drosophila model for TTR-associated amyloidosis
Background
A functional link has been established between the severe neurodegenerative disorder Familial amyloidotic polyneuropathy and the enhanced propensity of the plasma protein transthyretin (TTR) to form aggregates in patients with single point mutations in the TTR gene. Previous work has led to the establishment of an experimental model based on transgenic expression of normal or mutant forms of human TTR in Drosophila flies. Remarkably, the severity of the phenotype was greater in flies that expressed a single copy than with two copies of the mutated gene.Methodology/Principal Findings
In this study, we analyze the distribution of normal and mutant TTR in transgenic flies, and the ultrastructure of TTR-positive tissues to clarify if aggregates and/or amyloid filaments are formed. We report the formation of intracellular aggregates of 20 nm spherules and amyloid filaments in thoracic adipose tissue and in brain glia, two tissues that do not express the transgene. The formation of aggregates of nanospherules increased with age and was more considerable in flies with two copies of mutated TTR. Treatment of human neuronal cells with protein extracts prepared from TTR flies of different age showed that the extracts from older flies were less toxic than those from younger flies.Conclusions/Significance
These findings suggest that the uptake of TTR from the circulation and its subsequent segregation into cytoplasmic quasi-crystalline arrays of nanospherules is part of a mechanism that neutralizes the toxic effect of TTR. 相似文献994.
995.
996.
Adam Jozwiak Malgorzata Gutkowska Katarzyna Gawarecka Liliana Surmacz Anna Buczkowska Malgorzata Lichocka Julita Nowakowska Ewa Swiezewska 《The Plant cell》2015,27(12):3336-3353
Dolichol is a required cofactor for protein glycosylation, the most common posttranslational modification modulating the stability and biological activity of proteins in all eukaryotic cells. We have identified and characterized two genes, PPRD1 and -2, which are orthologous to human SRD5A3 (steroid 5α reductase type 3) and encode polyprenol reductases responsible for conversion of polyprenol to dolichol in Arabidopsis thaliana. PPRD1 and -2 play dedicated roles in plant metabolism. PPRD2 is essential for plant viability; its deficiency results in aberrant development of the male gametophyte and sporophyte. Impaired protein glycosylation seems to be the major factor underlying these defects although disturbances in other cellular dolichol-dependent processes could also contribute. Shortage of dolichol in PPRD2-deficient cells is partially rescued by PPRD1 overexpression or by supplementation with dolichol. The latter has been discussed as a method to compensate for deficiency in protein glycosylation. Supplementation of the human diet with dolichol-enriched plant tissues could allow new therapeutic interventions in glycosylation disorders. This identification of PPRD1 and -2 elucidates the factors mediating the key step of the dolichol cycle in plant cells which makes manipulation of dolichol content in plant tissues feasible. 相似文献
997.
Ajit Rayamajhi Sam Nightingale Nisha Keshary Bhatta Rupa Singh Elizabeth Ledger Krishna Prasad Bista Penny Lewthwaite Chandeshwar Mahaseth Lance Turtle Jaimie Sue Robinson Sareen Elizabeth Galbraith Malgorzata Wnek Barbara Wilmot Johnson Brian Faragher Rachel Kneen Michael John Griffiths Tom Solomon 《PloS one》2015,10(8)
998.
The present study was an attempt to investigate the subjectively perceived role of dreams. It examined the private concepts of dreams and dreaming, attitude toward dreams, and the influence of dreams on behavior, which can manifest in sharing dreams with other people, trying to interpret one's own dreams, believing they have special meaning, or behaving according to the clues given by the dream. The sample consisted of 47 participants, students ages 19-20. A structured interview, individually administered, was used. The results indicate interesting relationships between analyzed variables and gender; they also show individual differences in both common notions about dreams and the way dreams can influence other kinds of behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
999.
1000.
Suwalsky M Rivera C Sotomayor CP Jemiola-Rzeminska M Strzalka K 《Biophysical chemistry》2008,132(1):1-8
Methylation of inorganic arsenic has been regarded as a detoxification mechanism because its metabolites monomethylarsonic acid (MMA(v)) and dimethylarsinic acid (DMA(v)) are supposed to be less toxic than inorganic arsenite and arsenate. In recent years, however, this interpretation has been questioned. Additionally, there are insufficient reports concerning the effects of arsenic compounds on cell membrane structure and functions. With the aim to better understand the molecular mechanisms of the interaction of MMA(v) and arsenate with cell membranes, we have utilized molecular models consisting in bilayers of dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylethanolamine (DMPE), representative of phospholipid classes located in the outer and inner monolayers of many cell membranes including that of the human erythrocyte. The capacity of MMA(v) and arsenate to perturb the bilayer structures of DMPC and DMPE was evaluated by X-ray diffraction; the modifications of their thermotropic behavior were followed by differential scanning calorimetry (DSC), while DMPC large unilamellar vesicles (LUV) were studied by fluorescence spectroscopy. It was found that MMA(v) and arsenate did not structurally perturb DMPC bilayers; however, DMPE bilayers did suffer structural perturbations by MMA(v). DSC measurements also revealed that DMPE's thermotropic properties were significantly affected by arsenicals, where MMA(v) was more effective than arsenate, whilst only slight modifications were observed in the case of DMPC-MMA(v) system. 相似文献