117,467 research outputs found
Aspects of 8-[14C]Benzylaminopurine Metabolism in Phaseolus vulgaris
No full textPhaseolus vulgaris L. plants were supplied through the root with [8-14C]benzylaminopurine ([14C]BA). Collections of root, apex, and leaves were made 8 and 48 hours after labeling; ethanolic extracts of tissues were purified and subjected to thin layer chromatography on silica gel and/or cellulose powder.From [14C]BA at least two different metabolites originate, the BA riboside and ribotide. The balance among [14C]BA, the riboside, and the ribotide changed in time. The [14C]BA riboside was detected as the only labeled compound in the xylem sap collected from the stem. The biological function of BA riboside and ribotide is discussed
Oxygen concentration and ethylene production in roots and leaves of wheat - Short-term reaction in air after anoxic and hypoxic treatments
No full textSeven-day old wheat seedlings (Triticum aestivum L. cv. MEC) were incubated in small jars, fluxed with gas mixtures of nitrogen-oxygen (oxygen concentrations 0, 0.3, 1, 2.5, 10%) for up to 48 h. Effects of anoxia and hypoxia on ethylene evolution and ethylene-forming enzyme (EFE) activity were determined 1 h after the plants had been transferred to air, respectively. 1-aminocyclopropane-1-carboxylic acid (ACC) content was measured immediately after treatments. Results showed that the ethylene production is differently affected by oxygen deprivation in roots and leaves. The effects are more closely related to ACC accumulation than to the EFE activity. In leaves, ethylene evolution is almost unaffected by oxygen concentrations above ca 1%
Ethylene-responsive genes are differentially regulated during abscission, organ senescence and wounding in peach (Prunus persica)
No full textEthylene-responsive genes from peach (Prunes persica, L. Batsch) were isolated by differential screening of a cDNA library constructed from abscission zones in which cell separation had been evoked by treatment with the ethylene analogue propylene. DNA and deduced protein sequences of four selected clones, termed Prunus persica Abscission zone (PpAz), revealed homology to thaumatin-like proteins (PpAz8 and PpAz44), to proteins belonging to the PR4 class of pathogenesis-related (PR) proteins (PpAz89), and to fungal and plant beta-D-xylosidases (PpAz152). Expression analyses conducted on embrioctomized and CEPA-treated fruitlets as well as on fruit explants have shown that PpAz8, PpAz44 and PpAz89 are preferentially transcribed in the cells of the fruit abscission zone rather than in the non-zone tissues. The PpAz152 transcript showed a different accumulation pattern being consistently and promptly induced by wounding and only slightly stimulated by propylene. By contrast, a complex pattern of transcript accumulation was found for the four genes in response to the wounding of leaves and during organ development and senescence. Based on this evidence, the existence of multiple regulatory pathways underlying the differential expression of the four PpAz genes in the different tissues and physiological processes is hypothesized
Endo-β-1,4-glucanases are involved in peach fruit growth and ripening, and regulated by ethylene
No full textDuring peach (Prunus persica [L.] Batsch) fruit development and ripening the cell wall undergoes several structural and biochemical changes driven by several hydrolases. Among these, the endo-beta-1.4-D-glucanase (EGase, EC 3.2.1.4), or cellulase, may play a crucial role. Involvement of EGase throughout development and ripening of the fruit of cv. Redhaven was assessed by monitoring enzyme activity, specific polypeptide accumulation and gene transcription. During the four stages of growth EGase activity was high during S1 and in the early S2, declined during S3, and increased with the onset of ripening (S4). Two isoforms with isolectric points of 6.5 and 9.5 were identified. The pI 6.5 EGase was the only form present during the early stages of growth, whereas the pi 9.5 EGase was most abundant during ripening. The same isoforms were present in leaf and fruit abscission zones. The antibody raised against the pi 9.5 EGase, purified from lear abscission zones, cross-reacted with a protein of 54 kDa. A cDNA clone of 753 bp encoding peach EGase was obtained by RT-PCR. EGase transcripts, detectable only after amplification of total RNA by RT-PCR, were observed during S1, and at the preclimacteric and climacteric stages. However, the strongest hybridisation occurred at ripening, in correspondence with the maximal enzyme activity and polypeptide accumulation, which took place before the ethylene climacteric and in the early stage of flesh softening. Propylene treatments reduced EGase activity during the early stage of fruit growth but dramatically enhanced enzyme activity and the related transcript accumulation at ripening, and accelerated the loss of firmness. In fruit treated with 2,5-norbornadiene the softening process was strongly inhibited and the rise in EGase transcripts and activity did not take place. The results point to the EGases being involved in early fruit growth and the initial phases of softening. The presence of two isoforms and the dual effect of propylene on enzyme activity suggest that different EGase genes operate during the early and late developmental stages in peach fruit
Chemical thinning: ethylene and pre treatment fruit size influence enlargement, auxin transport, and apparent sink strength of French prune and 'Andross' peach
No full textEthephon applied to peach (Prunus persica L. cv. Andross) and French prune (Prunus domestica L. cv. Agen) at fruit developmental stages sensitive to ethylene-induced abscission reduced peach enlargement and the 14C-IAA transport capacities of excised peach pedicel segments. Sensitivity to (2-chloroethyl)phosphonic acid (ethephon) was inversely related to peach size prior to treatment. Triiodobenzoic acid (TIBA) increased abscission of control and ethephon-treated prunes.
Accumulation of label by fruit tissues of ethylene pretreated prune explants following xylem transport of 14C-sugar was reduced despite the absence of competing sinks and continued availability of sugar. These results provide evidence of a direct effect of ethylene on fruit tissues
Ethylene responsive genes are differentially regulated during peach fruit abscission
No full textEthylene responsive genes from peach (Prunus persica (L.) Batsch) were isolated by differential screening of a cDNA library constructed from abscission zones in which cell separation had been evoked by treatment with the ethylene analogue propylene. DNA and deduced protein sequences of four selected clones, termed as Prunus persica Abscission zone (PpAz), revealed homology to thaumatin-like proteins (PpAz8 and PpAz44), to proteins belonging to the PR4 class of pathogenesis related (PR) proteins (PpAz89), and to fungal and plant beta-D-xylosidases (PpAz152). Expression analyses conducted on embryoctomized and CEPA treated fruitlets as well as on fruit explants have shown that PpAz8, PpAz44 and PpAz89 are preferentially transcribed in the cells of the fruit abscission zone rather than in the non-zone tissues. PpAz152 transcript showed a different accumulation pattern being consistently and promptly induced by wounding and only slightly stimulated by propylene
Conferência da Haia de direito internacional privado: algumas tendências recentes
No full textLo scritto ripercorre gli orientamenti e i metodi di lavoro seguiti in tempi recenti dalla Conferenza dell'Aja di diritto internazionale privato nel perseguimento della sua missione, indicata dall'art. 1 del suo Statuto come consistente nel lavorare all'unificazione progressiva del diritto internazionale privato
Dominance induction of fruitlet shedding in Malus X domestica (L. Borkh): molecular changes associated with polar auxin transport
No full textBACKGROUND: Apple fruitlet abscission is induced by dominance, a process in which hormones such as auxin, cytokinins and strigolactone play a pivotal role. The response to these hormones is controlled by transcription regulators such as Aux/IAA and ARR, whereas auxin transport is controlled by influx and efflux carriers.
RESULTS: Seven partial clones encoding auxin efflux carriers (MdPIN1_A, MdPIN1_B, MdPIN10_A, MdPIN10_B, MdPIN4, MdPIN7_A and MdPIN7_B), three encoding auxin influx carriers (MdLAX1, MdLAX2 and MdLAX3) and three encoding type A ARR cytokinin response regulators (MdARR3, MdARR4 and MdARR6) were isolated by the use of degenerate primers. The organization of the PIN multigene family in apple is closer to Medicago truncatula than to Arabidopsis thaliana. The genes are differentially expressed in diverse plant organs and at different developmental stages. MdPIN1 and MdPIN7 are largely more expressed than MdPIN10 and MdPIN4. During abscission, the transcription of these genes increased in the cortex whereas in the seed a sharp fall was observed. The expression of these genes was found to be at least partially controlled by ethylene and auxin.
CONCLUSION: The ethylene burst preceding abscission of fruitlets may be responsible for the decrease in transcript level of MDPIN1, MDARR5 and MDIAA3 in seed. This situation modulates the status of the fruitlet and its fate by hampering the PAT from the seeds down through the abscission zone (AZ) and this brings about the shedding of the fruitlet
Peach (Prunus persica L. Batsch) allergen-encoding genes are developmentally regulated and affected by fruit load and light radiation
No full textThe fruits of Rosaceae species may frequently induce allergic reactions in both adults and children, especially in the Mediterranean area. In peach, true allergens and cross-reactive proteins may cause hypersensitive reactions involving a wide diversity of symptoms. Three known classes of allergenic proteins, namely, Pru p 1, Pru p 3, and Pru p 4, have been reported to be mostly involved, but an exhaustive survey of the proteins determining the overall allergenic potential, their biological functions, and the factors affecting the expression of the related genes is still missing. In the present study, the expression profiles of some selected genes encoding peach allergen isoforms were studied during fruit growth and development and upon different fruit load and light radiation regimens. The results indicate that the majority of allergen-encoding genes are expressed at their maximum during the ripening stage, therefore representing a potential risk for peach consumers. Nevertheless, enhancing the light radiation and decreasing the fruit load achieved a reduction of the transcription rate of most genes and a possible decrease of the overall allergenic potential at harvest. According to these data, new growing practices could be set up to obtain hypoallergenic peach fruits and eventually combined with the cultivation of hypoallergenic genotypes to obtain a significant reduction of the allergenic potential
Endo-beta 1,4 glucanases are involved in peach fruit growth and ripening and are regulated by ethylene
No full text- …
