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- Evaluating the Madeiran wheat germplasm for aluminum resistance using aluminium-induced callose formation in root apices as a markerPublication . Santos, Teresa M. M. dos; laski, Jan J.; Carvalho, Miguel Â. A. Pinheiro de; Taylor, Gregory J.; Vieira, Maria R. ClementeAluminum (Al) resistance of 57 Madeiran wheat cultivars was evaluated using callose content in root tips and root elongation as markers. Al induced callose formation was a very sensitive indicator of Al damage detecting wide range of genotypic differences existing in the Madeiran wheat germplasm. A weak, yet pos i tive cor re la tion (R2=0.285, P<0.05) between callose content and root elongation was found.
- Factors contributing to the development of aluminum resistance in the Madeiran maize germplasmPublication . Carvalho, Miguel Â. A. Pinheiro de; Slaski, Jan J.; Abreu, Ivo; Ganança, Filipe T.; Santos, Teresa M. M. dos; Freitas, Lurdes; Vieira, Maria R. Clemente; Nunes, Antonieta; Domingues, Ana; Taylor, Gregory J.
- Cytometric determination of genome size in Ruscus (Liliaceae) from the flora of MadeiraPublication . Carvalho, Miguel Â. A. Pinheiro de; Lucas, Iolanda C. Vale; Nieves Redondo, M. de las; Horjales, Marina
- Identification of aluminum resistant genotypes among Madeiran regional wheatsPublication . Carvalho, Miguel Â. A. Pinheiro de; Slaski, Jan J.; Santos, Teresa M. M. dos; Ganança, Filipe T.; Abreu, Ivo; Taylor, Gregory J.; Vieira, Maria R. Clemente; Popova, Tatyana N.; Franco, EmanuelForty-eight genotypes representing wheat diversity from the Island of Madeira were screened for resistance to aluminum (Al) in nutrient solution. Seeds of wheat used in the experiments were obtained from local farmers. The soil pH and content of ionic Al of plots cultivated with wheat were analyzed. The pH of topsoils varied between 3.83 and 6.59. The amount of ionic Al in soil samples varied between 0.38 and 1.36 cmol Al3 + per kg of soil and was positively correlated with the altitude of a plot. Eriochrome cyanine staining was used to evaluate the effect of Al ions on the root elongation. Seventy-two hour exposure of 3-day-old seedlings to 100 and 200 mM Al in nutrient solution revealed a high number of Al resistant genotypes among wheat germplasm. After withdrawal of Al stress, survival and root regrowth was observed in 28 and 23 genotypes screened at 100 and 200 mM Al in nutrient solution, respectively. Enhanced resistance to Al among Madeiran genotypes was associated with the amount of ionic Al in the soils. Complexity and various patterns of responses of tested cultivars to Al stress may suggest that Madeiran germplasm could be a valuable source of genes controlling Al resistance for conventional breeding programs and for studies of molecular bases of mechanisms of Al resistance.
- Citrate and isocitrate in plant metabolismPublication . Popova, Tatyana N.; Carvalho, Miguel Â. A. Pinheiro deThe relevance of citrate and isocitrate metabolism in plants is discussed in connection with the different pathways for their conversions. The routes for citrate and isocitrate conversions are incorporated into the system of cross-linked metabolic processes and may provide carbon skeletons for nitrogen assimilation and reducing equivalents for biosynthetic reactions, support the functioning of the glyoxylate cycle and play an important role in the TCA and energy metabolism as a whole. The possibility of the coupling of citrate and isocitrate metabolism with various electron transport systems is discussed from the point of view of the efficiency of the balancing cellular NAD P H Ž . Ž . rNAD P and ATP q rADP ratios. The role of citrate and isocitrate and their derivations as potent effectors of some enzymes is considered. Special attention is paid to the enzymes associated with citrate and isocitrate metabolism and to the mechanisms which regulate their activity. The possibilities of the coordination of the main processes of energy and biosynthetic metabolism at the level of citrate and isocitrate distribution are discussed.
- Helminth parasites from the stomach of conger eel, Conger conger, from Madeira Island, Atlantic OceanPublication . Costa, Graça; Santos, Maria J.; Costa, Luísa; Biscoito, Manuel; Carvalho, Miguel Â. A. Pinheiro de; Moreira, Egberto MeloGeographic variations in the diversity and prevalence of helminth parasites of fish can provide important clues as to the relatedness of fish populations. In the present work, the stomachs of 64 conger eels, Conger conger, collected during 1999 and 2000, were examined for the presence of parasites. Four fish were infected with L3 stages of the nematode Anisakis simplex s.l. (Anisakidae), 1 with the nematode Cristitectus congeri (Cystidicolidae), 1 with the acanthocephalan Rhadi norhynchus pristis, 17 with postlarvae of Sphyriocephalus tergestinus (Eucestoda: Trypanorhyncha), and 55 with Lecithochirium spp. (Digenea: Hemiuridae). The hemiurids were the most abundant parasites, with a total of 385 individuals recovered. Strong aggregated distributions were found for both the digeneans, Lecithochirium musculus and Lecithochirium fusiforme, with variance-to-mean ratios (s 2 /x) and index of discrepancy (D) 13.98 and 0.672 (for L. musculus) and 8.08 and 0.90 for L. fusiforme, respectively. Intensity of L. musculus, L. fusiforme, and S. tergestinus showed significant relationships with depth of capture. Differences in number of species and prevalence were found between Madeira and the Atlantic coasts of the Iberian Peninsula.
- Regulation of mitochondrial NADP-isocitrate dehydrogenase in rat heart during ischemiaPublication . Popova, Tatiana; Carvalho, Miguel Â. A. Pinheiro de; Matasova, Larisa; Medvedeva, LiliyaThe changes in the regulation of at mitochondrial NADP-isocitrate dehydrogenase (NADP-ICDH) in a rat heart during have been analysed. Increase of enzyme activity in the cytosol and mitochondria of the heart ischemia was detected. Catalytic properties of the mitochondrial NADP-ICDH at norm and pathology have been compared on homogeneous enzyme preparations. Enzyme from the normoxic and ischemic heart showed the same electrophoretical mobility and molecular mass. Enzyme isolated from the ischemic heart mitochondria demonstrated higher activation energy and lower thermal stability. NADP-isocitrate dehydrogenase at the normoxic and ischemic conditions exhibited different Km for substrates and regulatory behaviour in relation to ATP, ADP, 2-oxoglutarate, citrate, malate, reduced and oxidised glutathione. The inhibitory effect of the Fe2+ and H2O2 mixture associated with the generation of hydroxyl radicals was lower in the ischemic enzyme. We hypothesise that the specific features of regulation behaviour of NADP-ICDH from the ischemic tissues permits the enzyme to supply NADPH to the glutathione reductase/glutathione peroxidase system.