1,071 research outputs found

    Presenilin-1 regulates induction of hypoxia inducible factor-1α: altered activation by a mutation associated with familial Alzheimer's disease

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    <p>Abstract</p> <p>Background</p> <p>Mutations in presenilin-1 (<it>Psen1</it>) cause familial Alzheimer's disease (FAD). Both hypoxia and ischemia have been implicated in the pathological cascade that leads to amyloid deposition in AD. Here we investigated whether Psen1 might regulate hypoxic responses by modulating induction of the transcription factor hypoxia inducible factor 1-α (HIF-1α).</p> <p>Results</p> <p>In fibroblasts that lack Psen1 induction of HIF-1α was impaired in response to the hypoxia mimetic cobalt chloride, as well as was induction by insulin and calcium chelation. Reintroduction of human Psen1 using a lentiviral vector partially rescued the responsiveness of <it>Psen1-/- </it>fibroblasts to cobalt chloride induction. HIF-1α induction did not require Psen1's associated γ-secretase activity. In addition, the failure of insulin to induce HIF-1α was not explicable on the basis of failed activation of the phosphatidylinositol 3-kinase (PI3K/Akt) pathway which activated normally in <it>Psen1-/- </it>fibroblasts. Rather we found that basal levels of HIF-1α were lower in <it>Psen1-/- </it>fibroblasts and that the basis for lower constitutive levels of HIF-1α was best explained by accelerated HIF-1α degradation. We further found that Psen1 and HIF-1α physically interact suggesting that Psen1 may protect HIF-1α from degradation through the proteasome. In fibroblasts harboring the M146V Psen1 FAD mutation on a mouse Psen1 null background, metabolic induction of HIF-1α by insulin was impaired but not hypoxic induction by cobalt chloride. Unlike <it>Psen1-/- </it>fibroblasts, basal levels of HIF-1α were normal in FAD mutant fibroblasts but activation of the insulin-receptor pathway was impaired. Interestingly, in <it>Psen1-/- </it>primary neuronal cultures HIF-1α was induced normally in response to cobalt chloride but insulin induction of HIF-1α was impaired even though activation of the PI3K/Akt pathway by insulin proceeded normally in <it>Psen1-/- </it>neuronal cultures. Basal levels of HIF-1α were not significantly different in <it>Psen1-/- </it>neurons and HIF-1α levels were normal in <it>Psen1-/- </it>embryos.</p> <p>Conclusions</p> <p>Collectively these studies show that Psen1 regulates induction of HIF-1α although they indicate that cell type specific differences exist in the effect of Psen1 on induction. They also show that the M146V Psen1 FAD mutation impairs metabolic induction of HIF-1α, an observation that may have pathophysiological significance for AD.</p

    Bacterial Symbionts in Ceratitis capitata

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    Ceratitis capitata (Diptera: Tephritidae) is responsible for extensive damage in agriculture with important economic losses. Several strategies have been proposed to control this insect pest including insecticides and the Sterile Insect Technique. Traditional control methods should be implemented by innovative tools, among which those based on insect symbionts seem very promising. Our study aimed to investigate, through the 16S Miseq analysis, the microbial communities associated with selected organs in three different medfly populations to identify possible candidates to develop symbiont-based control approaches. Our results confirm that Klebsiella and Providencia are the dominant bacteria in guts, while a more diversified microbial community has been detected in reproductive organs. Concertedly, we revealed for the first time the presence of Chroococcidiopsis and Propionibacterium as stable components of the medfly's microbiota. Additionally, in the reproductive organs, we detected Asaia, a bacterium already proposed as a tool in the Symbiotic Control of Vector-Borne Diseases. A strain of Asaia, genetically modified to produce a green fluorescent protein, was used to ascertain the ability of Asaia to colonize specific organs of C. capitata. Our study lays the foundation for the development of control methods for C. capitata based on the use of symbiont bacteria

    Monitoring of sensory attributes used in the quality payment system of Trentingrana cheese

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    Abstract Trentingrana is a Protected Designation of Origin (PDO) hard cheese manufactured in the valleys of Trento province (eastern Italian Alps) by several small cooperative dairies linked in a consortium. Nine months after production, wheels are delivered to a shared facility, ripened up to 18 mo, and assessed by a panel of 8 experts for 7 sensory attributes; namely, external aspect, rind thickness, paste color, texture, odor, taste, and aroma. The evaluation takes place every 2 mo on wheels sampled within each dairy. Based on the results of the assessment, dairies receive a price premium or penalty depending on a quality index, which is the weighted sum of the scores attributed to each sampled wheel. Sensory scores and quality index of 652 wheels representing 11 dairies and 10 yr of production were analyzed using a model that included fixed effects of dairy, year, and season of production, and first-order interactions between them. The coefficients of determination ranged from 0.50 (texture) to 0.66 (aroma). All factors significantly affected the studied traits, with the exception of interactions between dairy and season of production for texture and external aspect, and between year and season of production for odor. Dairy was the most important source of variation for visually assessed traits (external aspect, rind thickness, paste color, and texture) and for quality index, whereas year of production was the most important for flavor attributes (odor, taste, and aroma). The latter traits were always highly correlated among them and with the quality index, whereas correlations among visually assessed attributes, between them and flavor attributes, and between them and the quality index were more erratic. The sensory evaluation performed by the panel of experts has proven to be a useful tool to define the quality index and address the payment system of Trentingrana cheese, but it has some limitations in correctly describing the sensory profile of cheese and identifying specific defects and possible remedies

    Quantificação de propagulos de Fusarium solani f. sp. glycines no solo. (b)

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    Trabalho apresentado na XXVII ReuniĂŁo de Pesquisa de Soja da RegiĂŁo Sul, ChapecĂł, 1999

    Bioactivity of volatile organic compounds by Aureobasidium species against gray mold of tomato and table grape

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    Aureobasidium strains isolated from diverse unconventional environments belonging to the species A. pullulans, A. melanogenum, and A. subglaciale were evaluated for Volatile Organic Compounds (VOCs) production as a part of their modes of action against Botrytis cinerea of tomato and table grape. By in vitro assay, VOCs generated by the antagonists belonging to the species A. subglaciale showed the highest inhibition percentage of the pathogen mycelial growth (65.4%). In vivo tests were conducted with tomatoes and grapes artificially inoculated with B. cinerea conidial suspension, and exposed to VOCs emitted by the most efficient antagonists of each species (AP1, AM10, AS14) showing that VOCs of AP1 (A. pullulans) reduced the incidence by 67%, partially confirmed by the in vitro results. Conversely, on table grape, VOCs produced by all the strains did not control the fungal incidence but were only reducing the infection severity (< 44.4% by A. pullulans; < 30.5% by A. melanogenum, and A. subglaciale). Solid-phase microextraction (SPME) and subsequent gas chromatography coupled to mass spectrometry identified ethanol, 3-methyl-1-butanol, 2-methyl-1-propanol as the most produced VOCs. However, there were differences in the amounts of produced VOCs as well as in their repertoire. The EC50 values of VOCs for reduction of mycelial growth of B. cinerea uncovered 3-methyl-1-butanol as the most effective compound. The study demonstrated that the production and the efficacy of VOCs by Aureobasidium could be directly related to the specific species and pathosystem and uncovers new possibilities for searching more efficient VOCs producing strains in unconventional habitats other than plant

    Transcriptional variation of sensory-related genes in natural populations of Aedes albopictus

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    BACKGROUND: The Asian tiger mosquito, Aedes albopictus, is a highly dangerous invasive vector of numerous medically important arboviruses including dengue, chikungunya and Zika. In four decades it has spread from tropical Southeast Asia to many parts of the world in both tropical and temperate climes. The rapid invasion process of this mosquito is supported by its high ecological and genetic plasticity across different life history traits. Our aim was to investigate whether wild populations, both native and adventive, also display transcriptional genetic variability for functions that may impact their biology, behaviour and ability to transmit arboviruses, such as sensory perception. RESULTS: Antennal transcriptome data were derived from mosquitoes from a native population from Ban Rai, Thailand and from three adventive Mediterranean populations: Athens, Greece and Arco and Trento from Italy. Clear inter-population differential transcriptional activity was observed in different gene categories related to sound perception, olfaction and viral infection. The greatest differences were detected between the native Thai and the Mediterranean populations. The two Italian populations were the most similar. Nearly one million quality filtered SNP loci were identified. CONCLUSION: The ability to express this great inter-population transcriptional variability highlights, at the functional level, the remarkable genetic flexibility of this mosquito species. We can hypothesize that the differential expression of genes, including those involved in sensory perception, in different populations may enable Ae. albopictus to exploit different environments and hosts, thus contributing to its status as a global vector of arboviruses of public health importance. The large number of SNP loci present in these transcripts represents a useful addition to the arsenal of high-resolution molecular markers and a resource that can be used to detect selective pressure and adaptive changes that may have occurred during the colonization process

    Exploring blueberry aroma complexity by chromatographic and direct-injection spectrometric techniques

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    Blueberry (Vaccinium spp.) fruit consumption has increased over the last 5 years, becoming the second most important soft fruit species after strawberry. Despite the possible economic and sensory impact, the blueberry volatile organic compound (VOC) composition has been poorly investigated. Thus, the great impact of the aroma on fruit marketability stimulates the need to step forward in the understanding of this quality trait. Beside the strong effect of ripening, blueberry aroma profile also varies due to the broad genetic differences among Vaccinium species that have been differently introgressed in modern commercial cultivars through breeding activity. In the present study, divided into two different activities, the complexity of blueberry aroma was explored by an exhaustive untargeted VOC analysis, performed by two complementary methods: SPME-GC-MS (solid phase microextraction-gas chromatography-mass spectrometry) and PTR-ToF-MS (proton transfer reaction-time of flight-mass spectrometry). The first experiment was aimed at determining the VOC modifications during blueberry ripening for five commercially representative cultivars ("Biloxi," "Brigitta Blue," "Centurion," "Chandler," and "Ozark Blue") harvested at four ripening stages (green, pink, ripe, and over-ripe) to outline VOCs dynamic during fruit development. The objective of the second experiment was to confirm the analytical capability of PTR-ToF-MS to profile blueberry genotypes and to identify the most characterizing VOCs. In this case, 11 accessions belonging to different Vaccinium species were employed: V. corymbosum L. ("Brigitta," "Chandler," "Liberty," and "Ozark Blue"), V. virgatum Aiton ("Centurion," "Powder Blue," and "Sky Blue"), V. myrtillus L. (three wild genotypes of different mountain locations), and one accession of V. cylindraceum Smith. This comprehensive characterization of blueberry aroma allowed the identification of a wide pull of VOCs, for the most aldehydes, alcohols, terpenoids, and esters that can be used as putative biomarkers to rapidly evaluate the blueberry aroma variations related to ripening and/or senescence as well as to genetic background differences. Moreover, the obtained results demonstrated the complementarity between chromatographic and direct-injection mass spectrometric techniques to study the blueberry aroma

    Identification of pheromone components and their binding affinity to the odorant binding protein CcapOBP83a-2 of the Mediterranean fruit fly, Ceratitis capitata

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    The Mediterranean fruit fly (or medfly), Ceratitis capitata (Wiedemann; Diptera: Tephritidae), is a serious pest of agriculture worldwide, displaying a very wide larval host range with more than 250 different species of fruit and vegetables. Olfaction plays a key role in the invasive potential of this species. Unfortunately, the pheromone communication system of the medfly is complex and still not well established. In this study, we report the isolation of chemicals emitted by sexually mature individuals during the “calling” period and the electrophysiological responses that these compounds elicit on the antennae of male and female flies. Fifteen compounds with electrophysiological activity were isolated and identified in male emissions by gas chromatography coupled to electroantennography (GC–EAG). Within the group of 15 identified compounds, 11 elicited a response in antennae of both sexes, whilst 4 elicited a response only in female antennae. The binding affinity of these compounds, plus 4 additional compounds known to be behaviourally active from other studies, was measured using C. capitata OBP, CcapOBP83a-2. This OBP has a high homology to Drosophila melanogaster OBPs OS-E and OS-F, which are associated with trichoid sensilla and co-expressed with the well-studied Drosophila pheromone binding protein LUSH. The results provide evidence of involvement of CcapOBP83a-2 in the medfly's odorant perception and its wider specificity for (E,E)-α-farnesene, one of the five major compounds in medfly male pheromone emission. This represents the first step in the clarification of the C. capitata and pheromone reception pathway, and a starting point for further studies aimed towards the creation of new powerful attractants or repellents applicable in the actual control strategies
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