194 research outputs found

    Genome-Wide Transcriptional Changes and Lipid Profile Modifications Induced by Medicago truncatula N5 Overexpression at an Early Stage of the Symbiotic Interaction with Sinorhizobium meliloti.

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    Plant lipid-transfer proteins (LTPs) are small basic secreted proteins, which are characterized by lipid-binding capacity and are putatively involved in lipid trafficking. LTPs play a role in several biological processes, including the root nodule symbiosis. The Medicago truncatula nodulin 5 (MtN5) LTP has been proved to positively regulate the nodulation capacity, controlling rhizobial infection and nodule primordia invasion. To better define the lipid transfer protein MtN5 function during the symbiosis, we produced MtN5-downregulated and -overexpressing plants, and we analysed the transcriptomic changes occurring in the roots at an early stage of Sinorhizobium meliloti infection. We also carried out the lipid profile analysis of wild type (WT) and MtN5-overexpressing roots after rhizobia infection. The downregulation of MtN5 increased the root hair curling, an early event of rhizobia infection, and concomitantly induced changes in the expression of defence-related genes. On the other hand, MtN5 overexpression favoured the invasion of the nodules by rhizobia and determined in the roots the modulation of genes that are involved in lipid transport and metabolism as well as an increased content of lipids, especially galactolipids that characterize the symbiosome membranes. Our findings suggest the potential participation of LTPs in the synthesis and rearrangement of membranes occurring during the formation of the infection threads and the symbiosome membrane

    Comparison of regeneration capacity and Agrobacterium-mediated cell transformation efficiency of different cultivars and rootstocks of Vitis spp. via organogenesis.

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    The success of in vitro plant regeneration and the competence of genetic transformation greatly depends on the genotype of the species of interest. In previous work, we developed a method for the efficient Agrobacterium-mediated genetic transformation via organogenesis of V. vinifera cultivar Thompson Seedless, by using meristematic bulk (MB) as starting tissue. In this study, we applied this method for the regeneration and transformation of MBs obtained from the Italian cultivar Ciliegiolo and two of the commonly used Vitis rootstocks, 110 Richter and Kober 5BB, in comparison with Thompson Seedless. The A. tumefaciens strain EHA105, harbouring pK7WG2 binary vector, was used for the transformation trials, which allowed selection through the enhanced-green fluorescent protein (eGFP) and the neomycin phosphotransferase (nptII) gene. Putative transformed tissues and/or shoots were identified by either a screening based on the eGFP expression alone or its use in combination with kanamycin in the medium. MBs obtained from Thompson Seedless showed the highest regeneration and transformation cell competence, which subsequently allowed the recovery of stably transformed plants. Ciliegiolo, 110 Richter, and Kober 5BB, produced actively growing transgenic calli showing eGFP fluorescence, more consistently on selective media, but had no regenerative competence

    Off-label Utilization of Antihypertensive Medications in Children

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    Objective— To examine off-label utilization and costs of antihypertensive drugs in children using a national sample of prescription claims. Design— Cross-sectional study. Setting— 2002 Medstat MarketScan Database, a national sample of outpatient prescription claims of children ≥18 years old enrolled in private, employer-sponsored health plans. Main Outcome Measures— Off-label use of antihypertensive drugs by patient age and costs of antihypertensives calculated as mean cost per child per 30-day fill. Results— One-half of the index antihypertensive prescription claims were off-label, based on minimum age criteria. Boys were more likely (56%) than girls (46%) to be prescribed off-label antihypertensives (p<0.001). Children aged ≥12 years were more likely to be prescribed off-label antihypertensives (53%) compared with children aged ≥5 (46%) and 6–11 years (42%, p<0.001). Off-label use varied significantly by class of antihypertensive drugs (p<0.001). Overall, off-label antihypertensives were significantly more expensive than on-label antihypertensives. Conclusions— Despite availability of often less expensive on-label alternatives for the same class of antihypertensive drugs, off-label antihypertensive drugs were prescribed frequently in children. These findings underscore the potential clinical and economic implications of common off-label prescribing, for children, their parents, physicians and payers. Originally published Ambulatory Pediatrics, Vol. 7, No. 4, July 200

    Stimulation programs for pediatric drug research – do children really benefit?

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    Most drugs that are currently prescribed in pediatrics have not been tested in children. Pediatric drug studies are stimulated in the USA by the pediatric exclusivity provision under the Food and Drug Administration Modernization Act (FDAMA) that grants patent extensions when pediatric labeling is provided. We investigated the effectiveness of these programs in stimulating drug research in children, thereby increasing the evidence for safe and effective drug use in the pediatric population. All drugs granted pediatric exclusivity under the FDAMA were analyzed by studying the relevant summaries of medical and clinical pharmacology reviews of the pediatric studies or, if these were unavailable, the labeling information as provided by the manufacturer. A systematic search of the literature was performed to identify drug utilization patterns in children. From July 1998 to August 2006, 135 drug entities were granted pediatric exclusivity. Most frequent drug groups were anti-depressants and mood stabilizers, ACE inhibitors, lipid-lowering preparations, HIV antivirals, and non-steroidal anti-inflammatory and anti-rheumatic drugs. The distribution of the different drugs closely matched the distribution of these drugs over the adult market, and not the drug utilization by children

    Genomic positional conservation identifies topological anchor point RNAs linked to developmental loci

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    BACKGROUND: The mammalian genome is transcribed into large numbers of long noncoding RNAs (lncRNAs), but the definition of functional lncRNA groups has proven difficult, partly due to their low sequence conservation and lack of identified shared properties. Here we consider promoter conservation and positional conservation as indicators of functional commonality. RESULTS: We identify 665 conserved lncRNA promoters in mouse and human that are preserved in genomic position relative to orthologous coding genes. These positionally conserved lncRNA genes are primarily associated with developmental transcription factor loci with which they are coexpressed in a tissue-specific manner. Over half of positionally conserved RNAs in this set are linked to chromatin organization structures, overlapping binding sites for the CTCF chromatin organiser and located at chromatin loop anchor points and borders of topologically associating domains (TADs). We define these RNAs as topological anchor point RNAs (tapRNAs). Characterization of these noncoding RNAs and their associated coding genes shows that they are functionally connected: they regulate each other’s expression and influence the metastatic phenotype of cancer cells in vitro in a similar fashion. Furthermore, we find that tapRNAs contain conserved sequence domains that are enriched in motifs for zinc finger domain-containing RNA-binding proteins and transcription factors, whose binding sites are found mutated in cancers. CONCLUSIONS: This work leverages positional conservation to identify lncRNAs with potential importance in genome organization, development and disease. The evidence that many developmental transcription factors are physically and functionally connected to lncRNAs represents an exciting stepping-stone to further our understanding of genome regulation

    Rabies and canine distemper virus epidemics in the red fox population of Northern Italy (2006–2010)

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    Since 2006 the red fox (Vulpes vulpes) population in north-eastern Italy has experienced an epidemic of canine distemper virus (CDV). Additionally, in 2008, after a thirteen-year absence from Italy, fox rabies was re-introduced in the Udine province at the national border with Slovenia. Disease intervention strategies are being developed and implemented to control rabies in this area and minimise risk to human health. Here we present empirical data and the epidemiological picture relating to these epidemics in the period 2006-2010. Of important significance for epidemiological studies of wild animals, basic mathematical models are developed to exploit information collected from the surveillance program on dead and/or living animals in order to assess the incidence of infection. These models are also used to estimate the rate of transmission of both diseases and the rate of vaccination, while correcting for a bias in early collection of CDV samples. We found that the rate of rabies transmission was roughly twice that of CDV, with an estimated effective contact between infected and susceptible fox leading to a new infection occurring once every 3 days for rabies, and once a week for CDV. We also inferred that during the early stage of the CDV epidemic, a bias in the monitoring protocol resulted in a positive sample being almost 10 times more likely to be collected than a negative sample. We estimated the rate of intake of oral vaccine at 0.006 per day, allowing us to estimate that roughly 68% of the foxes would be immunised. This was confirmed by field observations. Finally we discuss the implications for the eco-epidemiological dynamics of both epidemics in relation to control measures

    Promoter-bound METTL3 maintains myeloid leukaemia by m6A-dependent translation control.

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    N6-methyladenosine (m6A) is an abundant internal RNA modification in both coding and non-coding RNAs that is catalysed by the METTL3-METTL14 methyltransferase complex. However, the specific role of these enzymes in cancer is still largely unknown. Here we define a pathway that is specific for METTL3 and is implicated in the maintenance of a leukaemic state. We identify METTL3 as an essential gene for growth of acute myeloid leukaemia cells in two distinct genetic screens. Downregulation of METTL3 results in cell cycle arrest, differentiation of leukaemic cells and failure to establish leukaemia in immunodeficient mice. We show that METTL3, independently of METTL14, associates with chromatin and localizes to the transcriptional start sites of active genes. The vast majority of these genes have the CAATT-box binding protein CEBPZ present at the transcriptional start site, and this is required for recruitment of METTL3 to chromatin. Promoter-bound METTL3 induces m6A modification within the coding region of the associated mRNA transcript, and enhances its translation by relieving ribosome stalling. We show that genes regulated by METTL3 in this way are necessary for acute myeloid leukaemia. Together, these data define METTL3 as a regulator of a chromatin-based pathway that is necessary for maintenance of the leukaemic state and identify this enzyme as a potential therapeutic target for acute myeloid leukaemia
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