1,721,002 research outputs found
Identificazione di possibili sofisticazioni in preparati commerciali di Origano Mediterraneo ed analisi genetica di Origanum spp. mediante marcatori molecolari genomici: Random Amplified Polymorphic DNA (RAPD) e Sequence Characterized Amplified Region (SCAR)
No full textNel corso del Dottorato è stata sviluppata una procedura di identificazione, basata su marcatori molecolari genomici, delle specie vegetali principalmente rinvenute come adulteranti in preparati commerciali di Origano Mediterraneo, al fine di rendere veloce e trasferibile il processo di autenticazione e certificazione qualitativa della droga. Sono stati definiti i limiti di specificità e sensibilità del metodo, valutando la minima percentuale di contaminanti identificabile.
Come metodica di base dell’analisi molecolare si è scelto di utilizzare la tecnica PCR-RAPD, Random Amplified Polymorphic DNA (Williams et al., 1990; Welsh e McClelland 1990). L’analisi effettuata attraverso i marcatori molecolari RAPD presenta considerevoli vantaggi: vengono analizzati marcatori dominanti (caratteristica favorevole nelle indagini interspecifiche); è possibile individuare un elevato numero di polimorfismi; la metodica non richiede l’uso di elevati quantitativi di DNA e conoscenze a priori delle sequenze genomiche in esame.
Dall’analisi RAPD-PCR è stata successivamente derivata una seconda categoria di marcatori molecolari genomici altamente riproducibile e trasferibile, definita SCAR, Sequence Characterized Amplified Region (Paran e Michelmore, 1993).
Sono state inoltre ottimizzate la procedura di estrazione del DNA genomico a partire da campioni vegetali essiccati e ricchi in composti aromatici e la metodica di amplificazione PCR, al fine di rendere più veloce l’analisi di numeri elevati di campioni
Authentication of saffron (Crocus sativus L.) in different processed, retail products by means of SCAR markers
No full textA method based on Sequence-Characterized Amplified Regions (SCARs) was applied to 24 different food products composed by or containing different amounts of saffron (Crocus sativus L.), in order to detect adulteration/contamination with seven common bulking agents, namely Arnica montana L., Bixa orellana L., Calendula officinalis L., Carthamus tinctorius L., Crocus vernus L. (Hill), Curcuma longa L. and Hemerocallis sp. The food products screened included ground saffron, mixed seasonings and spices, ready-made dishes and herbal formulations. The method allowed a very good performance in both DNA extraction and amplification stages regardless of the presence of lipidic, sugary or polyphenolic substances and despite the presence of dried, stored and processed material. Two samples evidenced a contamination with C. vernus, four with Carthamus, one with Curcuma and one with Hemerocallis, while a product was found to contain no C. sativus. The recourse to SCAR markers may represent a fast, reliable and low-cost screening method for the authentication of a wide range of dried food products containing saffron. Despite the great attention paid by the food industry to the authentication of saffron, some common bulking agents can be present in retail foods, as the 21% of the screened samples was not composed by pure saffro
Quality Control of Saffron (Crocus sativus L.): Development of SCAR Markers for the Detection of Plant Adulterants Used as Bulking Agents.
No full textA method based on Sequence-Characterised Amplified Regions (SCARs) was developed from Random Amplified Polymorphic DNA markers (RAPDs) specific for Arnica montana L., Bixa orellana L., Calendula officinalis L., Carthamus tinctorius L., Crocus vernus L. (Hill), Curcuma longa L. and Hemerocallis sp., in order to detect these common bulking agents in commercial saffron (Crocus sativus). The method enabled the unequivocal detection of low amounts (up to 1%) of each adulterant, allowing the preemptive rejection of suspect samples. Its enforcement limits the number of samples to be subjected to further evaluation with pharmacognostic or phytochemical analyses, especially when multiple batches have to be evaluated in a short time. The dimension of the amplicons is suitable for the analysis of degraded DNA obtained from dried, stored, processed and finely ground commercial material. Proper SCAR markers may represent a fast, sensitive, reliable and low-cost screening method for the authentication of dried commercial saffron material
Un diverso assorbimento del solfato è responsabile della differente tolleranza al cromo di due ceppi dell’alga verde unicellulare Scendesmus acutus? I- ATP solforilasi.
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Interaction between OAS-TL and desulfhydrase activity in Cr(VI) tolerance in the freshwater green alga Scenedesmus acutus.
No full textQuality control of commercial Mediterranean oregano: Development of SCAR markers for the detection of the adulterants Cistus incanus L., Rubus caesius L. and Rhus coriaria L.
No full textA recent pharmacognostic survey showed a frequent adulteration of commercial Mediterranean oregano with dried plants having a similar silvery gray color ( Rhus coriaria L., Cistus spp. and Rubus spp.). If performed by skilled adulterators, the detection of this practice relies almost completely on pharmacognostic assays which are extremely laborious and time consuming, especially when multiple batches of oregano have to be evaluated. Sequence-characterized amplified regions markers (SCARs) were developed from three RAPD markers specific for these adulterants, in order to speed up the primary screening
of Origanumbatches and allow the pre-emptive rejection of suspect samples, thus narrowing the number of samples to be subjected to more careful pharmacognostic analyses. The SCAR primers gave rise to the amplification of specific bands of expected sizes which allowed the detection up to 1% of adulterating plants. The relatively short dimension of these amplicons is suitable for the analysis of potentially
degraded DNA obtained from dried and stored commercial material
Increase of chromium tolerance in Scenedesmus acutus after sulfur starvation: Chromium uptake and compartmentalization in two strains with different sensitivities to Cr(VI)
Full text linktIn photosynthetic organisms sulfate constitutes the main sulfur source for the biosynthesis of GSH and itsprecursor Cys. Hence, sulfur availability can modulate the capacity to cope with environmental stresses, aphenomenon known as SIR/SED (Sulfur Induced Resistance or Sulfur Enhanced Defence). Since chromatemay compete for sulfate transport into the cells, in this study chromium accumulation and tolerancewere investigated in relation to sulfur availability in two strains of the unicellular green alga Scenedesmusacutus with different Cr-sensitivities. Paradoxically, sulfur deprivation has been demonstrated to inducea transient increase of Cr-tolerance in both strains. Sulfur deprivation is known to enhance the sulfateuptake/assimilation pathway leading to important consequences on Cr-tolerance: (i) reduced chromateuptake due to the induction of high affinity sulfate transporters (ii) higher production of cysteine andGSH which can play a role both through the formation of unsoluble complexes and their sequestration ininert compartments. To investigate the role of the above mentioned mechanisms, Cr accumulation in totalcells and in different cell compartments (cell wall, membranes, soluble and miscellaneous fractions) wasanalyzed in both sulfur-starved and unstarved cells. Both strains mainly accumulated chromium in thesoluble fraction, but the uptake was higher in the wild-type. In this type a short period of sulfur starvationbefore Cr(VI) treatment lowered chromium accumulation to the level observed in the unstarved Cr-tolerant strain, in which Cr uptake seems instead less influenced by S-starvation, since no significantdecrease was observed. The increase in Cr-tolerance following S-starvation seems thus to rely on differentmechanisms in the two strains, suggesting the induction of a mechanism constitutively active in the Cr-tolerant strain, maybe a high affinity sulfate transporter also in the wild-type. Changes observed in thecell wall and membrane fractions suggest a strong involvement of these compartments in Cr-toleranceincrease following S-starvation
Is a different sulfate assimilation responsible for the different chromium tolerance of two strains of the green unicellular alga Scenedesmus acutus?-APS reductase
No full textIsolamento parziale di un gene di Scenedesmus acutus omologo al gene SULP della solfato permeasi cloroplastica di C. reinhardtii.
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