130,908 research outputs found
Perturbation of cytokinin and ethylene-signalling pathways explain the strong rooting phenotype exhibited by Arabidopsis expressing the Schizosaccharomyces pombe mitotic inducer, cdc25
Get PDFBackground
Entry into mitosis is regulated by cyclin dependent kinases that in turn are phosphoregulated. In most eukaryotes, phosphoregulation is through WEE1 kinase and CDC25 phosphatase. In higher plants a homologous CDC25 gene is unconfirmed and hence the mitotic inducer Schizosaccharomyces pombe (Sp) cdc25 has been used as a tool in transgenic plants to probe cell cycle function. Expression of Spcdc25 in tobacco BY-2 cells accelerates entry into mitosis and depletes cytokinins; in whole plants it stimulates lateral root production. Here we show, for the first time, that alterations to cytokinin and ethylene signaling explain the rooting phenotype elicited by Spcdc25 expression in Arabidopsis.
Results
Expressing Spcdc25 in Arabidopsis results in increased formation of lateral and adventitious roots, a reduction of primary root width and more isodiametric cells in the root apical meristem (RAM) compared with wild type. Furthermore it stimulates root morphogenesis from hypocotyls when cultured on two way grids of increasing auxin and cytokinin concentrations. Microarray analysis of seedling roots expressing Spcdc25 reveals that expression of 167 genes is changed by > 2-fold. As well as genes related to stress responses and defence, these include 19 genes related to transcriptional regulation and signaling. Amongst these was the up-regulation of genes associated with ethylene synthesis and signaling. Seedlings expressing Spcdc25 produced 2-fold more ethylene than WT and exhibited a significant reduction in hypocotyl length both in darkness or when exposed to 10 ppm ethylene. Furthermore in Spcdc25 expressing plants, the cytokinin receptor AHK3 was down-regulated, and endogenous levels of iPA were reduced whereas endogeous IAA concentrations in the roots increased.
Conclusions
We suggest that the reduction in root width and change to a more isodiametric cell phenotype in the RAM in Spcdc25 expressing plants is a response to ethylene over-production. The increased rooting phenotype in Spcdc25 expressing plants is due to an increase in the ratio of endogenous auxin to cytokinin that is known to stimulate an increased rate of lateral root production. Overall, our data reveal important cross talk between cell division and plant growth regulators leading to developmental changes
Analysis of Apple Flavours: The Use of Volatile Organic Compounds to Address Cultivar Differences and the Correlation between Consumer Appreciation and Aroma Profiling
No full textIn the selection of apple (Malus domestica Borkh) fruits, consumers predominantly use visual and organoleptic responses, such as aroma and texture, as quality/preference markers. Previous studies profiling the sensory properties and aroma profiles of apple varieties have provided a lexicon describing important attributes within the modalities of aroma, texture, and flavour. The range of volatile organic compounds (VOCs) produced by four apple cultivars was assessed by thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). To facilitate automated dynamic headspace extraction of the VOCs from bulk samples, a small multichamber thermal extraction system was used. Forty compounds were detected and putatively identified by mass spectral comparison with NIST libraries. Eight compounds were not previously identified in apples. Permutational multivariate analysis of variance (PerMANOVA) and canonical analysis of principal coordinates (CAP) done on the whole volatile organic compound profiles show separation of the four cultivars. The use of random forest classification enabled the determination of a minimum set of fifteen potential VOC markers that successfully differentiate the cultivars under study. Trends across samples, VOCs, and sensory evaluation are revealed. The association between 4-hexen-1-ol acetate with texture/consistency, and crispiness, and correlation of 2-methylbut-2-en-1-yl acetate with juiciness and acidity is shown for the first time. These sensory correlations indicate that the compounds determined by this experiment could be used as objective markers for the consumer appreciation of fresh apples, enabling the optimum conditions for processing and storage of individual cultivars to be identified without recourse to expensive sensory panels in every case. Such tests could also be used as part of routine quality control by the producer and retailer, reducing costs and eliminating waste due to batches of inferior product
San Giovanni in Fiore: morfologia urbana e territori
No full textIl presente contributo analizza, attraverso uno studio della cartografia storica e rilievi architettonici realizzati dagli autori, la relazione tra ambiente e architettura, in un’area montana compresa nella Calabria Citra che, nel 1188, vide la fondazione del primo monastero florense in Sila, ad opera di Gioacchino da Fiore.
Nello studio sugli insediamenti urbani, appaiono interessanti gli intrecci tra le motivazioni di ordine pratico (legate alla natura del suolo, all’approvvigionamento delle materie prime, al clima) e le questioni politico-religiose di governo del territorio. Si accennerà, quindi, ai rapporti tra l’organizzazione monastica florense e il potere politico, poiché le donazioni e le concessioni dei vari territori ci consentono, in parte, di definire gli ambiti territoriali abitati e sfruttati ai fini dell’agricoltura e del pascolo, nonché dell’estrazione del granito e della raccolta della pece. I piccoli aggregati urbani, che si sviluppano in maniera più sistematica a partire dal XVI secolo, si dislocavano su un territorio complesso, la cui orografia, accentuava l’isolamento connaturato all’organizzazione interna dei singoli feudi, nei quali il territorio rimase diviso fino all’inizio dell’Ottocento. Tale isolamento ha determinato il carattere essenziale degli agglomerati urbani e soprattutto dell’architettura, che si è espressa secondo forme e materiali che raccontano della complementarietà tra questa e l’ambiente.
Gli insediamenti d’alta quota, in particolare, presentano diversi e complessi problemi di impianto urbano, di collegamento e di sostentamento. Il presente contributo illustra, in maniera più estesa, come questi siano stati risolti nel caso di San Giovanni in Fiore, tra il secolo XVI e il secolo XIX. La configurazione urbana, determinata dal sapiente inserimento delle unità d’abitazione nel forte declivio del monte Difesa, dal tracciamento delle strade, dalla ingegnosa sistemazione degli slarghi, testimonia la sintonia tra paesaggio naturale e paesaggio costruito.This paper analyses, through the study of the historic cartography and architectural surveys made by its authors, the relationship between environment and architecture, in a mountain area in Calabria Citra where, in 1188, Gioacchino da Fiore founded the first Florensis monastery in Sila.
The study of the urban settlements has shown the interesting tangle of practical reasons (related to the nature of soil, the supply of raw materials and to climate) and political-religious matters of territorial administration. The relationship between Florensis monastic organization and political power is mentioned, as donations and concessions of the different territories allow us, partly, to determine built up areas exploited for agriculture, pasture, granite extraction and pitch collecting.
The small urban concentrations, which increased more systematically since the 16th century, were distributed in a complex area, whose orography heightened the isolation which characterized the domestic organization of each fief, in which the region remained divided until the early 19th century.
This isolation determined the basic nature of the urban agglomerations and above all the nature of architecture, which is characterized by shapes and materials that reflect the complementarity between architecture and environment.
High altitude settlements, in particular, have different and complex urban structure, connection and supply problems. This study explains, in more detail, how these problems were solved in San Giovanni in Fiore, between the 16th and the 19th centuries. The urban configuration, delineated by the masterly insertion of the dwelling units in the steep slope of the Monte Difesa, by the street layout and the ingenious placing of widenings, testifies to the harmony between natural and built landscapes
Use of TD-GC–TOF-MS to assess volatile composition during post-harvest storage in seven accessions of rocket salad (Eruca sativa). BELL L, SPADAFORA D.N. contributed equally to the work
No full textAn important step in breeding for nutritionally enhanced varieties is determining the effects of the postharvest
supply chain on phytochemicals and the changes in VOCs produced over time. TD-GC–TOF-MS
was used and a technique for the extraction of VOCs from the headspace using portable tubes is
described. Forty-two compounds were detected; 39 were identified by comparison to NIST libraries.
Thirty-five compounds had not been previously reported in Eruca sativa. Seven accessions were assessed
for changes in headspace VOCs over 7 days. Relative amounts of VOCs across 3 time points were significantly
different – isothiocyanate-containing molecules being abundant on ‘Day 0’. Each accession
showed differences in proportions/types of volatiles produced on each day. PCA revealed a separation
of VOC profiles according to the day of sampling. Changes in VOC profiles over time could provide a tool
for assessment of shelf life
L'arco di "Druso". Procedure per un rilevamento integrato
No full textQuesto lavoro presenta un primo risultato di una ricerca, svolta grazie alla collaborazione di studiosi nelle discipline della rappresentazione, del rilevamento e dell’archeologia, riguardante il cosiddetto Arco di Druso. Questo manufatto archeologico, risulta essere particolarmente complesso, riguardo la datazione ed interpretazione, in quanto presenta diverse strutture sovrapposte e stratificate nel tempo: una prima originaria (costruita in epoca pre-imperiale), relativa ad un arco di trionfo a tre fornici, una seconda riutilizzata come arco di un acquedotto (III sec. d. C.,) e una terza decorata da alcuni elementi architettonici (1800 ca.). Il lavoro di analisi dell’Arco di Druso, basato sulle necessarie indagini storiografiche, iconografiche e documentarie, ha avuto come principale obiettivo quello di fornire una descrizione grafica del manufatto che potesse essere, da una parte, quanto più accurata possibile dal punto di vista metrico-dimensionale e, dall’altra, rivelatrice dei diversi aspetti dell’edificio.
A questo scopo è stata sperimentata una metodologia di rilevamento che utilizza vari sistemi di misurazione: di tipo strumentale, topografico e GPS, fotogrammetrico e tradizionale diretto, che vanno a integrarsi tra di loro, in modo da restituire un modello tridimensionale informatizzato di riferimento per tutte le fasi successive di restituzione. Particolare importanza è stata data al rilevamento diretto, soprattutto nello studio degli elementi di dettaglio delle modanature che ha messo in evidenza alcuni aspetti indicatori delle diverse fasi costruttive, in particolare l’inserimento di elementi di restauro negli elementi dell’ordine architettonico del fronte Sud.
Il testo si divide in: una primo paragrafo introduttivo sullo stato di fatto, su una puntuale analisi iconografica, storica e documentaria dei recenti rilievi (D. Maestri), un secondo riguardo Il rilevamento integrato, secondo la descrizione delle diverse procedure di analisi, misurazione e restituzione grafica (M. Canciani), una terzo, riferito al rilevamento diretto ed alla elaborazione dei grafici di restituzione alla grande scala (G. Spadafora).
Molecular mechanisms underlying potential pathogen resistance in cannabis sativa
Get PDFCannabis (Cannabis sativa L.) is one of the earliest cultivated crops, valued for producing a broad spectrum of compounds used in medicinal products and being a source of food and fibre. Despite the availability of its genome sequences, few studies explore the molecular mechanisms involved in pathogen defense, and the underlying biological pathways are poorly defined in places. Here, we provide an overview of Cannabis defence responses against common pathogens, such as Golovinomyces spp., Fusarium spp., Botrytis cinerea and Pythium spp. For each of these pathogens, after a summary of their characteristics and symptoms, we explore studies identifying genes involved in Cannabis resistance mechanisms. Many studies focus on the potential involvement of disease-resistance genes, while others refer to other plants however whose results may be of use for Cannabis research. Omics investigations allowing the identification of candidate defence genes are highlighted, and genome editing approaches to generate resistant Cannabis species based on CRISPR/Cas9 technology are discussed. According to the emerging results, a potential defence model including both immune and defence mechanisms in Cannabis plant–pathogen interactions is finally proposed. To our knowledge, this is the first review of the molecular mechanisms underlying pathogen resistance in Cannabis
Developmental stimuli and stress factors affect expression of ClGLP1, an emerging allergen-related gene in Citrus limon.
No full textbe involved in many developmental and stress related processes. A novel GLP cDNA was isolated from
Citrus limon and structural features and genomic organization were investigated by in silico and Southern
blots analysis. In lemon, the ClGLP1 encodes a 24.38 kDa which possesses a conserved motif of plant GLPs
proteins. A phylogetic analysis mapped ClGLP1 as belonging to the GER3 subfamily into the GLP1 group of
large GLP family. ClGLP1 was differentially expressed in the various organs and was highest in mature
fruit. Moreover, expression in the fruit was tissue- and stage-related as well as dependent on agricultural
practice (organic vs conventional). ClGLP1 transcripts increased during the transition from the green (180
days after blooming) to the yellow (240 days after blooming) mature fruit and were strongly enhanced in
yellow mature fruit from organic compared with conventional culture. A sudden and systemic increase in
ClGLP1 expression level was observed in leaves injured by wounding, together with an increase of
endogenous H2O2 amount. Notably, an enhancement of H202 was observed in fruit peel during transition
from green to yellow fruit stage. All together our data showed that ClGLP1 expression can be modulated
in relation to both developmental stimuli and culture practices; evidence is also provided that through
an oxidase activity this gene could play a role in fruit maturation as well as in stress responses
Combining Thermal Desorption GC and TOF-MS for the Determination of Melon VOC Profiles
No full textThe quality and safety of ready-to-eat packaged foods—such as salads—is very difficult for
consumers and suppliers to judge, and improving this situation is the focus of a Europe-wide
research project. Part of the project is devoted to the development of better methods to detect
and analyze the volatile organic compounds released from relevant food types, in an effort to
identify biomarkers for quality and microbial contamination. This article examines one important
food—melon—and shows how a method based on thermal desorption with gas chromatography–
time-of-flight mass spectrometry (GC–TOF-MS) can elucidate how key volatiles vary
with the size of the melon pieces. The article highlights how such analytical information will be
of value in efforts to improve the quality and safety of ready-to-eat foods
Rocket salad aroma is affected by sampling method, species and degree of leaf damage
No full textRocket salad is a valuable commercial product often sold as a bagged ready to eat salad. Two
different species from the Brassicaceae family are sold as rocket salad: Diplotaxis tenuifolia and Eruca
sativa. Both are aromatic, and previous studies have shown that their aroma is composed of a complex
mixture of volatile organic compounds (VOCs) from several different chemical families. Of particular
interest are isothiocyanates that are generated from the metabolism of glucosinolates produced by
Brassicaceae species. Both types of rocket salad have a limited shelf-life and there has been interest in
assessing whether analysis of VOCs could be used to help set ‘use by dates’ assess quality changes, and
report on issues within the supply chain. However, different methods have been used to sample and
analyse the VOC profiles. Here we compare the profiles from D. tenuifolia using two VOC sampling
methods (solid phase microextraction, SPME) and sampling onto thermal desorption (TD) tubes. We
also compare the VOC profiles sampled onto TD tubes from both species from leaves subjected to different
levels of damage: intact, chopped and blended. We find that both the method of VOC sampling
and the level of leaf damage have important effects on the VOC profile. In the comparison, fewer VOCs
are detected when sampling with SPME compared to TD tubes. Overall, 41 different VOCs are detected
in the leaf damage experiment but many fewer are detected in intact leaves. While the two rocket
species are distinct based on the VOC profile of chopped leaves, they are not discriminated by VOC
profiles of blended or intact leaves. When species are considered separately VOC profile discriminates
level of damage. Very few isothiocyanates are detected in intact or chopped leaves, presumably due to
the requirement for leaf damage to activate their production from glucosinolates. To conclude, level of
leaf damage will strongly influence VOC profiles from rocket leaves, and medium damage seems to
elicit the most discriminatory profiles
- …
