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921.
Pilar Pérez Aitor Alonso Gloria Zita Rosa Morcuende Rafael Martínez-Carrasco 《Plant Growth Regulation》2011,65(3):439-447
Increases in growth temperature have been observed to affect photosynthesis differently under long-term exposure to ambient-
and twice ambient-air CO2 concentrations. This study investigates the causes of this interaction in wheat (Triticum aestivum L.) grown in the field over two consecutive years under temperature gradient chambers in ambient (370 μmol mol−1) or elevated (700 μmol mol−1) atmospheric CO2 concentrations and at ambient or ambient +4°C temperatures, with either a low or a high nitrogen supply. The photosynthesis-internal
CO2 response curves and the activity, activation state, kcat and amount of Ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco) were measured, as well as the soluble protein concentration
in flag leaves at ear emergence and 8–15 days after anthesis. A high nitrogen supply increased Vcmax, the Rubisco amount and activity and soluble protein contents, but did not significantly change the Rubisco kcat. Both elevated CO2 and above ambient temperatures had negative effects on Vcmax and Rubisco activity, but at elevated CO2, an increase in temperature did not decrease Vcmax or Rubisco activity in relation to ambient temperature. The amounts of Rubisco and soluble protein decreased with elevated
CO2 and temperature. The negative impact of elevated CO2 on Rubisco properties was somewhat counteracted at elevated temperatures by an increase in kcat. This effect can diminish the detrimental effects on photosynthesis of combined increases of CO2 and temperature. 相似文献
922.
Zorrilla-Fontanesi Y Cabeza A Domínguez P Medina JJ Valpuesta V Denoyes-Rothan B Sánchez-Sevilla JF Amaya I 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2011,123(5):755-778
Breeding for fruit quality traits in strawberry (Fragaria × ananassa, 2n = 8x = 56) is complex due to the polygenic nature of these traits and the octoploid constitution of this species. In order to
improve the efficiency of genotype selection, the identification of quantitative trait loci (QTL) and associated molecular
markers will constitute a valuable tool for breeding programs. However, the implementation of these markers in breeding programs
depends upon the complexity and stability of QTLs across different environments. In this work, the genetic control of 17 agronomical
and fruit quality traits was investigated in strawberry using a F1 population derived from an intraspecific cross between two contrasting selection lines, ‘232’ and ‘1392’. QTL analyses were
performed over three successive years based on the separate parental linkage maps and a pseudo-testcross strategy. The integrated
strawberry genetic map consists of 338 molecular markers covering 37 linkage groups, thus exceeding the 28 chromosomes. 33
QTLs were identified for 14 of the 17 studied traits and approximately 37% of them were stable over time. For each trait,
1–5 QTLs were identified with individual effects ranging between 9.2 and 30.5% of the phenotypic variation, indicating that
all analysed traits are complex and quantitatively inherited. Many QTLs controlling correlated traits were co-located in homoeology
group V, indicating linkage or pleiotropic effects of loci. Candidate genes for several QTLs controlling yield, anthocyanins,
firmness and l-ascorbic acid are proposed based on both their co-localization and predicted function. We also report conserved QTLs among
strawberry and other Rosaceae based on their syntenic location. 相似文献
923.
Leal E Fernández-Durán B Guillot R Ríos D Cerdá-Reverter JM 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2011,181(8):1035-1044
Repetitive aquaculture-related protocols may act as cyclic stressors that induce chronic stress in cultured fish. The sea
bass is particularly sensitive to stressful conditions and the mere presence of humans will disturb feeding behavior. In this
paper, we study whether chronic stress induced by repetition of acute stress protocols affects long-term feeding behavior
and growth performance in sea bass and whether exogenous cortisol may induce stress-like changes in these parameters. We demonstrate
that both chronic stress and dietary cortisol decrease food intake and have a negative effect on feed conversion efficiency,
severely impairing sea bass performance. Both experimental approaches induced changes in the daily feeding activity by lengthening
the active feeding periods. Fish subjected to a cyclic stressor modify their daily feeding pattern in an attempt to avoid
interference with the time of the stressor. The delay in feeding when fish are acutely and repeatedly stressed could be of
substantial adaptive importance. 相似文献
924.
Bezerra EH Rocha BA Nagano CS Bezerra Gde A Moura TR Bezerra MJ Benevides RG Sampaio AH Assreuy AM Delatorre P Cavada BS 《Biochemical and biophysical research communications》2011,(4):566-570
Diocleinae lectins are highly homologous in their primary structure which features metal binding sites and a carbohydrate recognition domain (CRD). Differences in the biological activity of legume lectins have been widely investigated using hemagglutination inhibition assays, isothermal titration microcalorimetry and co-crystallization with mono- and oligosaccharides. Here we report a new lectin crystal structure (ConBr) extracted from seeds of Canavalia brasiliensis, predict dimannoside binding by docking, identify the α-aminobutyric acid (Abu) binding pocket and compare the CRD of ConBr to that of homologous lectins. Based on the hypothesis that the carbohydrate affinity of lectins depends on CRD configuration, the relationship between tridimensional structure and endothelial NO synthase activation was used to clarify differences in biological activity. Our study established a correlation between the position of CRD amino acid side chains and the stimulation of NO release from endothelium. 相似文献
925.
Ghada Choho Hikmate Abriouel Nabil Ben Omar Rosario Lucas López Elena Ortega Magdalena Martínez-Cañamero Amin Laglaoui Saïd Barrijal Antonio Gálvez 《World journal of microbiology & biotechnology》2008,24(7):997-1001
A bacteriocin-producing lactic acid bacterium (strain 2.5) isolated from cow’s milk used in cheese production from Northern
Morocco was selected for its strong anti-listerial activity. The producer strain was identified as Enterococcus faecalis by molecular methods. Strain 2.5 carried the genetic determinants for the two-peptide enterococcal bacteriocin enterocin
1071, and the active bacteriocin was purified to homogeneity by reversed-phase chromatography from culture broths of the producer
strain. Strain 2.5 carried two plasmids (of ∼7 and 40 kb). Characterization of strain 2.5 at biosafety level indicated that
this strain is non-haemolytic, and lacks the genetic determinants for most of the virulence factors described in enterococci
(cylB, cylM, gelE, ace and agg) although it carried the genetic determinants cylA, efaAfs as well as determinants for the sex pheromone peptides cpd, cob, and ccf. Strain 2.5 was resistant to tetracycline, rifampicin, and ciprofloxacin, but it was sensitive to penicillin, ampicillin,
vancomycin, and teicoplanin. Results from the present study support the potential role of strain 2.5 as an anti-listerial
agent to be tested in traditional fermented foods. 相似文献
926.
Graciela Gil-Romera Mercedes García Antón Juan A. Calleja 《Vegetation History and Archaeobotany》2008,17(6):653-666
New pollen results and radiocarbon dating from a valley mire in south-western Spain are presented. This is a region where
few palaeoecological records have been preserved and the sequence yields important new palaeobotanical evidence for the late
Holocene. The landscape is shown as having been largely open woodland, but more wooded than at present. The vegetation history
of the last four millennia in these montane territories of south-western Iberia is discussed in the light of anthropogenic
indicators, archaeological and documentary archives; fire incidence and climate change. Alnus is the predominant pollen type, although a decline is noted during the last couple of centuries. Its presence is connected
with local topography behaving as a phreatophyte, that is, a plant which obtains a significant amount of water from the zone
of saturated soil. A framework is also provided for the age and ecological dynamics of some major woodland taxa—Betula, Corylus, Ilex, evergreen and deciduous oaks, Ericaceae and Pinus. In addition, the natural status of several pollen taxa and local trends in biodiversity are discussed. We consider that
the results of our work will have important implications for the understanding of the vegetation history in a floristically
very rich area, with a noticeable diversity of woody taxa, and a relatively well preserved ecosystem structure. 相似文献
927.
Mike Maunder Angela Leiva Eugenio Santiago-Valentín Dennis W. Stevenson Pedro Acevedo-Rodríguez Alan W. Meerow Milcíades Mejía Colin Clubbe Javier Francisco-Ortega 《The Botanical review》2008,74(1):197-207
While the Caribbean is a recognized “biodiversity hotspot”, plant conservation has not received adequate attention; particularly,
given the high levels of endemism in many plant groups. Besides establishing protected areas, there needs to be a sustained
effort to study the taxonomy, systematics and ecology of the flora. Recent phylogenetic studies have shown high levels of
endemism and conservation studies indicate a large propotion of the flora is threatened with extinction. Eight recommendations
are given for plant conservation in the region. 相似文献
928.
Insect-associated microbes exhibit a wide range of interactions with their hosts. One example of such interactions is the
insect-driven dispersal of microorganisms, which plays an essential role in the ecology of several microbes. To study dispersal
of microorganisms by leaf-cutting ants (Formicidae: Attini), we applied culture-dependent methods to identify the filamentous
fungi and yeasts found in two different body parts of leaf-cutting ant gynes: the exoskeleton and the infrabuccal pocket.
The gynes use the latter structure to store a pellet of the ants’ symbiotic fungus during nest founding. Many filamentous
fungi (n = 142) and yeasts (n = 19) were isolated from the gynes’ exoskeleton. In contrast, only seven filamentous fungi and three yeasts isolates were
recovered from the infrabuccal pellets, suggesting an efficient mechanism utilized by the gynes to prevent contamination of
the symbiotic fungus inoculum. The genus Cladosporium prevailed (78%) among filamentous fungi whereas Aureobasidium, Candida and Cryptococcus prevailed among yeasts associated with gynes. Interestingly, Escovopsis, a specialized fungal pathogen of the leaf-cutting ant-fungus symbiosis, was not isolated from the body parts or from infrabuccal
pellets of any gynes sampled. Our results suggest that gynes of the leaf-cutter ants Atta laevigata and A. capiguara do not vertically transmit any particular species of yeasts or filamentous fungi during the foundation of a new nest. Instead,
fungi found in association with gynes have a cosmopolitan distribution, suggesting they are probably acquired from the environment
and passively dispersed during nest foundation. The possible role of these fungi for the attine ant–microbial symbiosis is
discussed. 相似文献
929.
Cruz-Rangel S Hernández-Benítez R Vázquez-Juárez E López-Dominguez A Pasantes-Morales H 《Neurochemical research》2008,33(8):1518-1524
Activation of protein-activated receptor (PAR-1) by thrombin potentiates the hyposmotic efflux of 3H-d-aspartate and 3H-taurine from cultured cerebellar astrocytes. This effect is mediated by a thrombin-elicited increase in cytosolic Ca2+ levels [Ca2+]i and the activation of phosphoinositide-3-kinase (PI3K). These signalling pathways operate independently showing additive
effects if prevented simultaneously. The contribution of the Ca2+-mediated pathway to thrombin-increased d-aspartate or taurine efflux, evaluated by the inhibitory effect of preventing [Ca2+]i rise, was higher for d-aspartate (64% efflux decrease) than for taurine (40% decrease). The PI3K blocker decreased 48% and 36% d-aspartate and taurine efflux, respectively. Hyposmolarity increases phosphorylation of EGFR and c-src, but thrombin did not
enhance this effect. Blockade of EGFR/src phosphorylation marginally reduced (11–14%) the hyposmolarity plus thrombin efflux
of d-aspartate; taurine efflux was more sensitive to these blockers (18–26%). Since thrombin has no effect increasing EGFR/src
phosphorylation in astrocytes, the contribution of this transactivation pathway may represent the inhibition of the hyposmotic
efflux solely.
Special issue article in honor of Dr. Ricardo Tapia. 相似文献
930.
Micuda S Sispera L Hodac M Parízek P Fuksa L Brcáková E Cerman J Cermanová J Martínková J 《Physiological research / Academia Scientiarum Bohemoslovaca》2007,56(3):307-313
The 24-hour urinary excretion of 6-beta-hydroxycortisol (6beta-OHC) and the urinary ratio of 6beta- hydroxycortisol/cortisol (6beta-OHC/UFC) have been proposed as noninvasive probes for human cytochrome P450 3A4 isoform (CYP3A4). In this study, we evaluated within- and between-day variability of 6beta-OHC excretion and 6beta-OHC/UFC ratio in nine Caucasian men with cardiac disease. Each study participant was asked to collect 24-hour urine specimens during four consecutive days in five standardized time intervals. Concentrations of UFC and 6beta-OHC were determined by immunoassay and the high-performance liquid chromatographic (HPLC) method, respectively. The HPLC method was accurate and precise, as indicated by the recovery rate of 96.5-103.3 % and less than 5.2 % and 6.3 % of the coefficient of variation for within-run and between-run assay, respectively. In patients, diurnal variations in UFC and 6beta-OHC excretion were parallel. Consequently, 6beta-OHC/UFC ratio remained stable during the day. Both, 6beta-OHC excretion and 6beta-OHC/UFC ratio showed significant relationship between 24-hour value and values measured in corresponding collection periods with best correlations obtained from night interval (22.00-06.00, r = 0.86-0.91). These results indicated that urinary 6beta-OHC excretion and 6beta-OHC/UFC ratio measured in overnight/morning urine could precisely reflect 24-hour values even in severely ill patients. In addition, a simple and sensitive HPLC method was described for determination of 6beta-OHC in urine. 相似文献