118,372 research outputs found
Iron deficiency affects nitrogen metabolism in cucumber (<it>Cucumis sativus</it> L.) plants
No full textAbstract Background Nitrogen is a principal limiting nutrient in plant growth and development. Among factors that may limit NO3- assimilation, Fe potentially plays a crucial role being a metal cofactor of enzymes of the reductive assimilatory pathway. Very few information is available about the changes of nitrogen metabolism occurring under Fe deficiency in Strategy I plants. The aim of this work was to study how cucumber (Cucumis sativus L.) plants modify their nitrogen metabolism when grown under iron deficiency. Results The activity of enzymes involved in the reductive assimilation of nitrate and the reactions that produce the substrates for the ammonium assimilation both at root and at leaf levels in Fe-deficient cucumber plants were investigated. Under Fe deficiency, only nitrate reductase (EC 1.7.1.1) activity decreased both at the root and leaf level, whilst for glutamine synthetase (EC 6.3.1.2) and glutamate synthase (EC 1.4.1.14) an increase was found. Accordingly, the transcript analysis for these enzymes showed the same behaviour except for root nitrate reductase which increased. Furthermore, it was found that amino acid concentration greatly decreased in Fe-deficient roots, whilst it increased in the corresponding leaves. Moreover, amino acids increased in the xylem sap of Fe-deficient plants. Conclusions The data obtained in this work provided new insights on the responses of plants to Fe deficiency, suggesting that this nutritional disorder differentially affected N metabolism in root and in leaf. Indeed under Fe deficiency, roots respond more efficiently, sustaining the whole plant by furnishing metabolites (i.e. aa, organic acids) to the leaves.</p
The Vigani Cabinet - Analysis of historical resinous materials by gas chromatography - mass spectrometry and infrared spectroscopy
No full textNatural resins have been in use for a long time and for manifold purposes resulting in a long and complex terminological history. The investigation of this history has so far been based on the connection between nomenclature and chemical composition. Because resin chemistry and the botanical classification of source plants are connected as well, the investigation of natural resins can be enhanced by adding taxonomy as an additional dimension, providing a more complex and complete picture of resin chemistry and resin use.
The Vigani Cabinet, a collection of 300-year-old pharmaceutical and chemical materials owned by Queens’ College, Cambridge (UK), allows doing just that. A wide range of historical literature provides information about contemporary terminology, botanical and geographical origin, manufacture, trade and properties of resinous materials from the 18th century. This contemporary context is a particular feature of the Cabinet, which allows adding a historical dimension to the correlations between terminology, chemical composition and taxonomy.
The dissertation thesis presented here provides an investigation of 17 botanical, 80 reference materials and samples from 24 natural resins from the Vigani Cabinet, studying these complex correlations and changes over time. The analytical method employed in this study was gas chromatography-mass spectrometry (GC-MS) with and without methylation with trimethylsulfoniumhydroxide. This technique provided detailed molecular compositions of the studied materials. Analysed botanical samples are taken from Pinaceae, Cupressaceae and Pistacia resins, commerical references from Araucariaceae, Copaifera, Fabaceae, Myroxylon and Burseraceae. Additionally, the soluble fraction of Baltic amber was analysed.
Materials from the Vigani Cabinet analysed in this work were labelled as "turpentines", "pix burgundica", "sandaracha", "copaiba", "balsamum peruvianum and tolutanum", "mastiche", "anime", "copal", "elemi", "tacamahaca" and "succinum". Historical nomenclature of natural resins has not always been unequivocally associated with a botanical origin. The availability of natural resins changed throughout the centuries. Lack of knowledge, in particular about resins from over-seas, or adulterations resulting from changing harvesting methods, led to changes in trade names or variations in the composition of products traded under the same name. Generic names were used for resins with similar properties but different botanical (and geographical) origin. The thesis shows that a chemotaxonomic reference system is suitable for the identification of unknown resinous materials, and a number of new insights into the nomenclature of natural resins from the 17th and 18th century is obtained. The study of historical literature contributed in a significant way to the historico-cultural and archeometric research of the samples from the Vigani Cabinet and of natural resins in general and provided a basis for the interpretation of the chemical data from the Vigani samples.:CONTENTS
1 INTRODUCTION 1
1.1 Natural resins in a historical and modern context 1
1.2 The Vigani Cabinet and its historical background 3
1.3 Aim of the thesis - outline 6
2 LITERATURE REVIEW 8
2.1 Gymnosperm resins – conifer resins and products 9
2.1.1 Pinaceae 9
2.1.2 Cupressaceae 17
2.1.3 Araucariaceae 20
2.2 Angiosperm resins I – Fabales 21
2.3 Angiosperm resins II – Sapindales 30
2.3.1 Anacardiaceae 30
2.3.2 Burseraceae 35
2.3.3 Rutaceae 43
2.4 Fossil resins 45
2.5 Summary and research deficits 49
3 EXPERIMENTAL 53
3.1 Coupled gas chromatography and mass spectrometry 53
3.1.1 Materials 53
3.1.2 Sample preparation 54
3.1.3 Instrumentation 54
3.1.4 Data-Evaluation 58
3.2 Fourier transformation infrared spectroscopy 60
3.2.1 Sample preparation 61
3.2.2 Instrumentation 61
3.2.3 Data evaluation 61
4 RESULTS – REFERENCE MATERIALS 62
4.1 Gymnosperm resins – conifer resins and products 62
4.1.1 Pinaceae – Coniferous turpentines 62
4.1.1.1 Phytochemical markers – detection of adulterations 62
4.1.1.2 Aging by heat and light 73
4.1.2 Cupressaceae – Sandarac 80
4.1.3 Araucariaceae – Coniferous copals 88
4.1.4 Discussion 91
4.2 Angiosperm Resins I - Fabales 94
4.2.1 Copaifera – Copaiba balsam 94
4.2.2 Legume copals 102
4.2.3 Myroxylon – Balsam of Tolu and Peru 108
4.2.4 Discussion 117
4.3 Angiosperm resins II - Sapindales 120
4.3.1 Anacardiaceae – Pistacia resins 120
4.3.2 Burseraceae – Elemi, copal and others 127
4.3.3 Discussion 142
4.4 Fossil resins 144
4.4.1 Baltic amber 144
4.4.2 Discussion 153
4.5 Summary and research deficits 155
5 RESULTS – RESINOUS MATERIALS FROM THE VIGANI CABINET 160
5.1 Gymnosperm resins – conifer resins and products 162
5.1.1 1/8 Terebin. Strasb. 163
5.1.2 1/9 Tereb Com 170
5.1.3 1/10 Venice Turpentine 176
5.1.4 1/11 Venic. Turpent. 183
5.1.5 1/13 Tereb E Chio 188
5.1.6 A/23 Pix Burgundica 194
5.1.7 A/26 Sandaracha 203
5.2 Angiosperm resins I - Fabales 210
5.2.1 1/4 Balsam Cipivi 211
5.2.2 A/5 Gum Animi 218
5.2.3 La2/7 Unknown resin 228
5.2.4 1/31 Bals Peruv 230
5.2.5 2/1 Bals Peru 237
5.2.6 Z/17 Balsam Tolutanum 240
5. 3 Angiosperm resins II – Sapindales 245
5.3.1 A/11 Mastiche 246
5.3.2 1/14 Tereb i E Cypri 252
5.3.3 A/21 Gum Copal 258
5.3.4 A/24 [.] Elemi 268
5.3.5 A/22 Tacamahaca 276
5.3.6 Z/1 Tacamahaca 283
5.4 Fossil Resins 287
5.4.1 E/13 Succinum Citrinum 288
5.4.2 E/14 Succinum flavan 295
5.4.3 E/15 Succinum albam 302
5.4.4 E/16 Succinum nigram 307
5.4.5 F/13 L. Gagatis 313
6 CONCLUSIONS 316
7 REFERENCES 324
APPENDIX 365
Investigated materials from the Vigani Cabinet 366
Annotated list of historical literature 367
List of figures 374
List of tables 379
Compound lists 381
Atlas of mass spectra 422Naturharze werden schon lange für sehr unterschiedliche Zwecke verwendet. Dies hat zu einer oft komplizierten Terminologie geführt, deren Untersuchung sich bisher auf den Zusammenhang zwischen dem Namen des Harzes und seiner chemischer Zusammensetzung stützte. Letztere ist aber auch mit der botanischer Herkunft und damit der Biochemie der Stammpflanze verknüpft, weshalb man chemotaxonomische Aspekte für die systematische Untersuchung von Naturharzen als zusätzliche Variablen nutzen kann. Dadurch erhält man, wie die gezeigt werden soll, ein vollständigeres und komplexeres Bild der Chemie und Nutzung von Naturharzen.
Die hier präsentierte Untersuchung beschäftigt sich mit dem Vigani-Kabinett, einer 300 Jahre alten pharmazeutischen Materialiensammlung, die sich im Queens‘ College, Cambridge (UK), befindet. In der Literatur des ausgehenden 17. und des 18. Jahrhunderts finden sich zahlreiche Informationen zu Terminologie, botanischer und geographischer Herkunft, Verarbeitung, Handel und Eigenschaften von Naturharzen. Dadurch wird die historische Dimension des oben beschriebenen Zusammenhangs zwischen Terminologie, chemischer Zusammensetzung und Taxonomie erfahrbar.
In der Arbeit werden 17 botanische Proben, 80 moderne Referenzmaterialien und 24 Proben aus dem Vigani-Kabinett im Hinblick auf diese Zusammenhänge und Veränderungen untersucht.Die chemischen Analysen wurden mit gekoppelter Gaschromatografie-Massenspektrometrie mit und ohne Methylierung mit Trimethylsulfoniumhydroxid durchgeführt. Damit konnte die molekulare Zusammensetzung der Proben detailliert untersucht werden. Die untersuchten botanischen Proben stammten von Pinaceae, Cupressaceae und Pistaciaharzen, kommerzielle Referenzen von Araucariaceae, Copaifera, Fabaceae, Myroxylon und Burseraceaeharzen. Zusätzlich wurde noch die lösliche Fraktion von Baltischem Bernstein untersucht.
Die untersuchten Proben aus dem Vigani-Kabinett waren sowohl englisch als auch Latein mit "turpentines", "pix burgundica", "sandaracha", "copaiba", "mastiche", "anime", "copal", "elemi", "tacamahaca", "balsamum peruvianum and tolutanum" und "succinum" beschriftet.
Zusammenfassend lässt sich sagen, dass die historische Nomenklatur von Naturharzen nicht immer eindeutig mit ihrem botanischen Ursprung verknüpft war. Zusätzlich veränderte sich die Erhältlichkeit der Harze im Laufe der Jahrhunderte. Durch fehlendes Wissen, insbesondere für Materialien und Pflanzen aus Übersee, oder Verfälschungen aufgrund von veränderten Fördermethoden veränderten sich die Handelsnamen dieser Materialien oder die Zusammensetzung von Materialien, die unter demselben Namen gehandelt wurden. Harze mit ähnlichen Eigenschaften aber unterschiedlichen botanischen (und geographischen) Ursprungs trugen generische Namen. Die Arbeit zeigt jedoch, dass ein chemotaxonomisches Bezugssystem die Identifizierung von unbekannten Harzen ermöglicht, und zeigt eine Reihe neuer Erkenntnisse über die Nomenklatur von Naturharzen des 17. und 18. Jahrhunderts. Die Untersuchung historischer Quellen trug dabei sehr zur Erhellung des historisch-kulturellen und archeometrischen Hintergrundes und zur Interpretation der chemischen Daten der Vigani-Proben bei.:CONTENTS
1 INTRODUCTION 1
1.1 Natural resins in a historical and modern context 1
1.2 The Vigani Cabinet and its historical background 3
1.3 Aim of the thesis - outline 6
2 LITERATURE REVIEW 8
2.1 Gymnosperm resins – conifer resins and products 9
2.1.1 Pinaceae 9
2.1.2 Cupressaceae 17
2.1.3 Araucariaceae 20
2.2 Angiosperm resins I – Fabales 21
2.3 Angiosperm resins II – Sapindales 30
2.3.1 Anacardiaceae 30
2.3.2 Burseraceae 35
2.3.3 Rutaceae 43
2.4 Fossil resins 45
2.5 Summary and research deficits 49
3 EXPERIMENTAL 53
3.1 Coupled gas chromatography and mass spectrometry 53
3.1.1 Materials 53
3.1.2 Sample preparation 54
3.1.3 Instrumentation 54
3.1.4 Data-Evaluation 58
3.2 Fourier transformation infrared spectroscopy 60
3.2.1 Sample preparation 61
3.2.2 Instrumentation 61
3.2.3 Data evaluation 61
4 RESULTS – REFERENCE MATERIALS 62
4.1 Gymnosperm resins – conifer resins and products 62
4.1.1 Pinaceae – Coniferous turpentines 62
4.1.1.1 Phytochemical markers – detection of adulterations 62
4.1.1.2 Aging by heat and light 73
4.1.2 Cupressaceae – Sandarac 80
4.1.3 Araucariaceae – Coniferous copals 88
4.1.4 Discussion 91
4.2 Angiosperm Resins I - Fabales 94
4.2.1 Copaifera – Copaiba balsam 94
4.2.2 Legume copals 102
4.2.3 Myroxylon – Balsam of Tolu and Peru 108
4.2.4 Discussion 117
4.3 Angiosperm resins II - Sapindales 120
4.3.1 Anacardiaceae – Pistacia resins 120
4.3.2 Burseraceae – Elemi, copal and others 127
4.3.3 Discussion 142
4.4 Fossil resins 144
4.4.1 Baltic amber 144
4.4.2 Discussion 153
4.5 Summary and research deficits 155
5 RESULTS – RESINOUS MATERIALS FROM THE VIGANI CABINET 160
5.1 Gymnosperm resins – conifer resins and products 162
5.1.1 1/8 Terebin. Strasb. 163
5.1.2 1/9 Tereb Com 170
5.1.3 1/10 Venice Turpentine 176
5.1.4 1/11 Venic. Turpent. 183
5.1.5 1/13 Tereb E Chio 188
5.1.6 A/23 Pix Burgundica 194
5.1.7 A/26 Sandaracha 203
5.2 Angiosperm resins I - Fabales 210
5.2.1 1/4 Balsam Cipivi 211
5.2.2 A/5 Gum Animi 218
5.2.3 La2/7 Unknown resin 228
5.2.4 1/31 Bals Peruv 230
5.2.5 2/1 Bals Peru 237
5.2.6 Z/17 Balsam Tolutanum 240
5. 3 Angiosperm resins II – Sapindales 245
5.3.1 A/11 Mastiche 246
5.3.2 1/14 Tereb i E Cypri 252
5.3.3 A/21 Gum Copal 258
5.3.4 A/24 [.] Elemi 268
5.3.5 A/22 Tacamahaca 276
5.3.6 Z/1 Tacamahaca 283
5.4 Fossil Resins 287
5.4.1 E/13 Succinum Citrinum 288
5.4.2 E/14 Succinum flavan 295
5.4.3 E/15 Succinum albam 302
5.4.4 E/16 Succinum nigram 307
5.4.5 F/13 L. Gagatis 313
6 CONCLUSIONS 316
7 REFERENCES 324
APPENDIX 365
Investigated materials from the Vigani Cabinet 366
Annotated list of historical literature 367
List of figures 374
List of tables 379
Compound lists 381
Atlas of mass spectra 42
Ricostruzione tridimensionale, mediante tomografia, delle modificazioni ultrastruturali di mitocondri indotte da una carenza di Fe in Cucumis sativus L
No full textLa disponibilità di ferro condiziona il ciclo vitale delle piante. Infatti, il Fe è un elemento essenziale per la crescita e lo sviluppo in quanto importante cofattore nei processi fotosintetici e respiratori. Data l’importanza che i mitocondri ricoprono nella cellula si è ipotizzato che essi possano essere coinvolti in un meccanismo di percezione e trasduzione del segnale in condizioni di Fe carenza [1]. La caratterizzazione delle modificazioni indotte da Fe carenza a carico dei mitocondri potrebbe fornire informazioni utili per comprendere i meccanismi che regolano l’omeostasi del Fe nelle piante. In questo lavoro sono stati caratterizzati i cambiamenti dell’ultrastruttura mitocondriale in foglie di piante di cetriolo allevate in presenza (+Fe) e in assenza (-Fe) di Fe. L’ultrastruttura mitocondriale è stata osservata tramite microscopia elettronica a trasmissione (TEM) e tomografia elettronica che consentono di ottenere un modello di ricostruzione 3D delle strutture cellulari. Queste analisi hanno permesso di osservare che: i) nei tessuti fogliari la conformazione morfologica dei mitocondri appare conforme al modello noto come cristae junction model (in cui le creste si presentano come vescicole all’interno della matrice); ii) la carenza di Fe altera sia il numero che il volume delle creste rispetto alla condizione +Fe. I cambiamenti ultrastrutturali osservati nei mitocondri –Fe riflettono uno stato metabolico caratterizzato da una rallentata attività della catena respiratoria rispetto a mitocondri +Fe. L' analisi western blot su frazioni purificate ha permesso di osservare in mitocondri –Fe cambiamenti significativi nell’espressione di alcune proteine appartementi alla catena respiratoria rispetto a quelli controllo. La caratterizzazione sia delle variazioni ultrastrutturali che funzionali dei mitocondri indotte da Fe carenza rappresenta un approccio efficace per comprendere il ruolo di questi organelli nella risposta della pianta a tale stress nutrizionale.
[1] Vigani et al., (2013). Trends Plant Sci., 18 : 305-31
Decisioni di pensionamento e investimento in salute
No full textDecisioni di pensionamento e investimento in salut
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Proteomic characterization of iron deficiency responses in Cucumis sativus L. roots
No full textBackground: Iron deficiency induces in Strategy I plants physiological, biochemical and molecular modifications
capable to increase iron uptake from the rhizosphere. This effort needs a reorganization of metabolic pathways to
efficiently sustain activities linked to the acquisition of iron; in fact, carbohydrates and the energetic metabolism
has been shown to be involved in these responses. The aim of this work was to find both a confirmation of the
already expected change in the enzyme concentrations induced in cucumber root tissue in response to iron
deficiency as well as to find new insights on the involvement of other pathways.
Results: The proteome pattern of soluble cytosolic proteins extracted from roots was obtained by 2-DE. Of about
two thousand spots found, only those showing at least a two-fold increase or decrease in the concentration were
considered for subsequent identification by mass spectrometry. Fifty-seven proteins showed significant changes,
and 44 of them were identified. Twenty-one of them were increased in quantity, whereas 23 were decreased in
quantity. Most of the increased proteins belong to glycolysis and nitrogen metabolism in agreement with the
biochemical evidence. On the other hand, the proteins being decreased belong to the metabolism of sucrose and
complex structural carbohydrates and to structural proteins.
Conclusions: The new available techniques allow to cast new light on the mechanisms involved in the changes
occurring in plants under iron deficiency. The data obtained from this proteomic study confirm the metabolic
changes occurring in cucumber as a response to Fe deficiency. Two main conclusions may be drawn. The first one
is the confirmation of the increase in the glycolytic flux and in the anaerobic metabolism to sustain the energetic
effort the Fe-deficient plants must undertake. The second conclusion is, on one hand, the decrease in the amount
of enzymes linked to the biosynthesis of complex carbohydrates of the cell wall, and, on the other hand, the
increase in enzymes linked to the turnover of proteins
Square Dancing with the Stars to Enhance Dynamic Hirschman Linkages?
No full textIn this Presidential Address, the author takes the reader on a reconnaissance of his life and time as a regional scientist. He points out scenery he found scintillating along the way, hoping that some may pick up the banner and chew on a few of the ideas for a while. He suggests a revisit to Albert O. Hirschman’s notion of key sectors and more empirical analysis related to Marcus Berliant’s and Masahisa Fujita’s notion of knowledge creation and transfer.Presidential Address, San Antonio, Texas, March 29, 2014 (53rd Meetings of the Southern Regional Science Association
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Modulation of enzymatic activities and iron responsive gene expression in response to changes of the iron nutritional status in Cucumis sativus L.
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