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Institution

University of Córdoba (Spain)

EducationCordova, Spain
About: University of Córdoba (Spain) is a education organization based out in Cordova, Spain. It is known for research contribution in the topics: Population & Catalysis. The organization has 12006 authors who have published 22998 publications receiving 537842 citations. The organization is also known as: University of Córdoba (Spain) & Universidad de Córdoba.


Papers
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Journal ArticleDOI
TL;DR: This paper summarizes recent findings in Chlamydomonas to provide an integrated perspective on the adaptation of organisms to the availability of nitrogen, and how these organisms adapt to changing environmental conditions.
Abstract: Inorganic nitrogen is an essential nutrient for photosynthetic organisms. Its efficient use in nature involves adaptation of the organisms to the availability of the nitrogen supply, to changing environmental conditions, and to the provision of carbon and other nutrients. The unicellular alga Chlamydomonas provides a useful model to identify not only each of the components participating in the assimilative process in a species, but also the regulatory networks modulating their activity. A remarkable fact is the ample array of transporters for inorganic nitrogen compounds operating in this single cell: 13 putative nitrate/nitrite transporters and eight putative ammonium transporters. However, for nitrate, only a few of them participate as the main suppliers of nitrogen for cell growth, and others probably function to adapt nitrogen utilization efficiency to conditions depending not only on the nitrogen source available but also on other nutrients and environmental conditions. This paper summarizes recent findings in Chlamydomonas to provide an integrated perspective.

161 citations

Journal ArticleDOI
TL;DR: The results indicate that ghrelin exerts a direct stimulatory action on porcine GH release that is not additive with that of GHRH and requires the contribution of a multiple, complex set of interdependent intracellular signaling pathways.
Abstract: Ghrelin is a newly discovered peptide that binds the receptor for GH secretagogues (GHS-R). The presence of both ghrelin and GHS-Rs in the hypothalamic-pituitary system, together with the ability of ghrelin to increase GH release, suggests a hypophysiotropic role for this peptide. To ascertain the intracellular mechanisms mediating the action of ghrelin in somatotropes, we evaluated ghrelin-induced GH release from pig pituitary cells both under basal conditions and after specific blockade of key steps of cAMP-, inositol phosphate-, and Ca 2 -dependent signaling routes. Ghrelin stimulated GH release at concentrations ranging from 10 10 to 10 6 M. Its effects were comparable with those exerted by GHRH or the GHS L-163,255. Combined treatment with ghrelin and GHRH or L-163,255 did not cause further increases in GH release, whereas somatostatin abolished the effect of ghrelin. Blockade of phospholipase C or protein kinase C inhibited ghrelininduced GH secretion, suggesting a requisite role for this route in ghrelin action. Unexpectedly, inhibition of either adenylate cyclase or protein kinase A also suppressed ghrelininduced GH release. In addition, ghrelin stimulated cAMP production and also had an additive effect with GHRH on cAMP accumulation. Ghrelin also increased free intracellular Ca 2 levels in somatotropes. Moreover, ghrelin-induced GH release was entirely dependent on extracellular Ca 2 influx through L-type voltage-sensitive channels. These results indicate that ghrelin exerts a direct stimulatory action on porcine GH release that is not additive with that of GHRH and requires the contribution of a multiple, complex set of interdependent intracellular signaling pathways. (Endocrinology 144: 5372–5380, 2003)

160 citations

Journal ArticleDOI
TL;DR: A decrease in spring precipitation, which is the main driver of radial growth, is the most plausible cause of recent forest decline and the sharp growth reduction and widespread defoliation of the most affected pine plantations of Scots pine make their future persistence in drought-prone sites unlikely under the forecasted warmer and drier conditions.
Abstract: The negative impacts of severe drought on the growth and vigor of tree species and their relationship with forest decline have not been properly evaluated taking into account the differential responses to such stress of trees, sites and species. We evaluated these responses by quantifying the changes in radial growth of plantations of four pine species (Pinus sylvestris, Pinus nigra, Pinus pinaster, Pinus halepensis) which showed distinct decline and defoliation levels in southeastern Spain. We used dendrochronological methods, defoliation records, linear mixed models of basal area increment and dynamic factor analysis to quantify the responses of trees at the species and individual scales to site conditions and drought stress. In the region a temperature rise and a decrease in spring precipitation have led to drier conditions during the late twentieth century characterized by severe droughts in the 1990s and 2000s. As expected, the defoliation levels and the reductions in basal area increment were higher in those species more vulnerable to drought-induced xylem embolism (P. sylvestris) than in those more resistant (P. halepensis). Species adapted to xeric conditions but with high growth rates, such as P. pinaster, were also vulnerable to drought-induced decline. The reduction in basal area increment and the defoliation events occurred after consecutive severe droughts. A decrease in spring precipitation, which is the main driver of radial growth, is the most plausible cause of recent forest decline. The sharp growth reduction and widespread defoliation of the most affected pine plantations of Scots pine make their future persistence in drought-prone sites unlikely under the forecasted warmer and drier conditions.

160 citations

Journal ArticleDOI
TL;DR: Sunflower 7-hydroxylated simple coumarins may play a defensive role against O. cernua parasitism by preventing successful germination, penetration and/or connection to the host vascular system.
Abstract: The interaction of the parasitic plant Orobanche cernua with resistant and susceptible cultivars of Helianthus annuus L. was investigated. Using different bioassays to evaluate the early stages of the parasite life cycle (germination, attachment, penetration, and establishment), differences were observed between O. cernua-resistant and O. cernua-susceptible sunflower varieties. Germination of O. cernua seeds in the presence of resistant sunflower roots was approximately half that of germination in the presence of susceptible roots, and germinated seeds displayed enhanced browning symptoms. Parasite radicles or host-tissue around the contact point turned brown after O. cernua attachment to sunflower roots, especially in the resistant varieties. These observations suggested the possible accumulation of toxic compounds as a defence strategy in the resistant sunflower varieties. Sunflower 7-hydroxylated simple coumarins may play a defensive role against O. cernua parasitism by preventing successful germination, penetration and/or connection to the host vascular system. This hypothesis is supported by the following data: (i) coumarins inhibited the in vitro germination of O. cernua seeds induced by the strigol analogue GR(24) and caused a browning reaction in germinated seeds and (ii) resistant sunflowers accumulated higher levels of coumarins in roots and excreted greater amounts than susceptible varieties in response to O. cernua infection.

160 citations


Authors

Showing all 12089 results

NameH-indexPapersCitations
Jose M. Ordovas123102470978
Liang Cheng116177965520
Pedro W. Crous11580951925
Munther A. Khamashta10962350205
Luis Serrano10545242515
Raymond Vanholder10384140861
Carlos Dieguez10154536404
David G. Bostwick9940331638
Leon V. Kochian9526631301
Abhay Ashtekar9436637508
Néstor Armesto9336926848
Manuel Hidalgo9253841330
Rafael de Cabo9131735020
Harald Mischak9044527472
Manuel Tena-Sempere8735123100
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202333
2022133
20211,640
20201,619
20191,517
20181,348