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11.
Community composition and sensitivity of periphyton to atrazine in flowing waters: the role of environmental factors 总被引:4,自引:0,他引:4
Helena Guasch Núria Ivorra Volker Lehmann Maria Paulsson Montserrat Real Sergi Sabater 《Journal of applied phycology》1998,10(2):203-213
The relationship between environmental variables, community composition and the sensitivity of periphyton on artificial substrata
to the herbicide atrazine (EC50 values obtained by concentration-effect curves of photosynthesis to atrazine) was studied for 20 stream and river sites on
a latitudinal across Europe (Sweden, The Netherlands, Spain). Sensitivity to atrazine was higher in Swedish than in the Spanish
or Dutch sites. Direct gradient analyses were used to relate diatom taxa and algal groups with environmental variables. A
first redundancy analysis (RDA) based on diatom taxa showed a pollution gradient (atrazine and nutrient concentration) associated
to diatom taxa that are indicators of different degrees of pollution. A second RDA based on algal groups showed that diatom-dominated
communities corresponded both to sites at higher altitudes and less industrialized areas and to sites with higher atrazine
concentration; Cyanobacteria were the most common in industrial areas, whereas Chlorophyceae dominated in sites with high
water temperature and alkalinity. Linear regression analyses were applied to find the relationship between the ordination
axes obtained and the EC50 values. First axes of both RDA showed significant or marginally significant relationship with atrazine sensitivity. Regression
analyses for the Spanish sites indicated that the sensitivity to atrazine was related with light conditions (EC50 was positively correlated with light) and the percentage of different algal groups (EC50 was positively correlated with the percentage of diatoms and negatively correlated with the percentage of green algae). The
results indicating that differences in sensitivity are related to environmental variables such as light, nutrients or atrazine
concentration, permitted us to identify biological indicators of sensitivity to atrazine in lotic systems: Bacillariophyceae-dominated
periphyton communities were more tolerant than Chlorophyceae and Chrysophyceae-dominated communities. In addition, diatom
taxa found to be tolerant to atrazine in this study have been considered in the literature to be tolerant to organic pollution.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
12.
Tur R Magraner J Catret M Elorriaga M Ivorra MD D'Ocon P Bermejo A Cabedo N Cortes D Anselmi E 《Life sciences》2000,67(13):1535-1548
In the present study we examine the mechanism by which thaligrisine, a bisbenzyltetrahydroisoquinoline alkaloid, inhibits the contractile response of vascular smooth muscle. The work includes functional studies on rat isolated aorta and tail artery precontracted with noradrenaline or KCl. In other experiments rat aorta was precontracted by caffeine in the presence or absence of extracellular Ca2+. In order to assess whether thaligrisine interacts directly with calcium channel binding sites or with alpha-adrenoceptors we examined the effect of the alkaloid on [3H]-(+)-cis diltiazem, [3H]-nitrendipine and [3H]-prazosin binding to cerebral cortical membranes. The functional studies showed that the alkaloid inhibited in a concentration-dependent manner the contractile response induced by depolarization in rat aorta (IC50 = 8.9+/-2.9 microM, n=5) and in tail artery (IC50 = 3.04+/-0.3 microM, n=6) or noradrenaline induced contraction in rat aorta (IC50 = 23.0+/-0.39 microM, n=9) and in tail artery (IC50 = 3.8+/-0.9 microM, n=7). In rat aorta, thaligrisine concentration-dependently inhibited noradrenaline-induced contraction in Ca2+-free solution (IC50 = 13.3 microM, n=18). The alkaloid also relaxed the spontaneous contractile response elicited by extracellular calcium after depletion of noradrenaline-sensitive intracellular stores (IC50 = 7.7 microM, n=4). The radioligand receptor-binding study showed that thaligrisine has higher affinity for [3H]-prazosin than for [3H]-(+)-cis-diltiazem binding sites, with Ki values of 0.048+/-0.007 microM and 1.5+/-1.1 microM respectively. [3H]-nitrendipine binding was not affected by thaligrisine. The present work provides evidence that thaligrisine shows higher affinity for [3H]-prazosin binding site than [3H]-(+)-cis-diltiazem binding sites, in contrast with tetrandrine and isotetrandrine that present similar affinity for both receptors. In functional studies thaligrisine, acted as an alpha1-adrenoceptor antagonist and as a Ca2+ channel blocker, relaxing noradrenaline or KCl-induced contractions in vascular smooth muscle. This compound specifically inhibits the refilling of internal Ca2+-stores sensitive to noradrenaline, by blocking Ca2+-entry through voltage-dependent Ca2+-channels. 相似文献
13.
14.
Martinez S Madrero Y Elorriaga M Noguera MA Cassels B Sobarzo E D'Ocon P Ivorra MD 《Life sciences》1999,64(14):1205-1214
The selectivity of 3-nitrosoboldine and different halogenated derivatives of boldine (3-bromoboldine, 3,8-dibromoboldine and 3-chloroboldine) for alpha1-adrenoceptor subtypes was studied by examining [3H]-prazosin competition binding in rat cerebral cortex. In the competition experiments [3H]-prazosin binding was inhibited completely by all the compounds tested. The inhibition curves displayed shallow slopes which could be subdivided into high and low affinity components. The relative order of affinity and selectivity for alpha1A-adrenoceptors was 3-bromoboldine = 3,8-dibromoboldine = 3-chloroboldine > boldine > 3-nitrosoboldine. The competition curves for 3-bromoboldine remained shallow and biphasic following chloroethylclonidine treatment. Whereas the relative contribution of the high affinity sites increased, the 3-bromoboldine affinities at its high and low affinity sites remained similar to those obtained in untreated membranes. 3-Bromoboldine, 3,8-dibromoboldine, 3-chloroboldine and 3-nitrosoboldine did not significantly displace [3H]-(+)-cis-diltiazem binding to rat cerebral cortex membranes. This activity was lower than that shown by boldine. Compared to boldine, halogen (bromine or chlorine) substitution at position 3 increases the alpha1A-adrenoceptor subtype selectivity and decreases the affinity for the benzothiazepine binding site at the calcium channel. Further halogen substitution at position 8 did not significantly improve this activity with respect to 3-bromoboldine. In contrast, the NO substitution at position 3 of boldine (3-nitrosoboldine) gives a loss of affinity and selectivity for alpha1-adrenoceptor subtypes. 相似文献
15.
Pauline Burger Jean-Frederic Terral Marie-Pierre Ruas Sarah Ivorra Sandrine Picq 《Vegetation History and Archaeobotany》2011,20(5):447-458
Abundant and diverse Prunus fruitstone remains from cherries, plums, sloes, peaches, etc. are frequently recovered from archaeological waterlogged contexts
such as wells, latrines, lake dwellings etc. in Europe. The distinction between most of the Prunus species, based on traditional morphological characters of the fruit stones, is usually not problematic. However the discrimination
between P. avium L., P. cerasus L. and related cherry species, based on classical criteria alone, often turns out to be ambiguous because of the increasing
number of varieties which have been bred since Roman times. By combining geometric and traditional morphometrical approaches,
the overall variation in shape and size of stones from French and Swiss excavations dating from the 1st century to the 16th
century a.d. were assessed. Among these important archaeobotanical data, the detailed examination of 100 waterlogged stones from the 16th
century H?tel-Dieu cesspit at Tours, France, revealed that the morphological diversity is structured into two distinct morphotypes
which diverge mainly according to geometrical features. Finally, the comparison between morphological features of these well-preserved
archaeological stones and modern reference material including P. avium, P. cerasus and P. × gondouinii, suggests that these two morphotypes, which have been initially attributed to P. avium (long stones) and P. avium/cerasus (rounded stones) according to traditional morphological parameters, would correspond to two different cultivated varieties,
both belonging to Prunus avium. Results presented in this work constitute new and preliminary data obtained during the development of this project that
throw light on morphological variability and biosystematic aspects. 相似文献
16.
Sarah Ivorra Muriel Gros‐Balthazard Sandrine Picq Margareta Tengberg Jean‐Christophe Pintaud 《Journal of Biogeography》2012,39(5):929-941
Aim The main purpose of this work is to understand the origin, history, historical biogeography and mechanisms of date palm (Phoenix dactylifera L.) domestication. Location Seeds of uncultivated Phoenix individuals from isolated Oman populations, cultivated date palm varieties of various geographical origins and other related Phoenix species were analysed. Additionally, well‐preserved seeds from Egyptian archaeological sites (14th century bc to 8th century ad ) were compared with the morphometric reference model based on the analysis of modern material. Methods Elliptic Fourier transforms (EFT), a morphometric method applied to shape outline analysis, were used to characterize seed shape and to quantify morphological diversity in P. dactylifera and related species. Results Analysis of seed outlines by EFT (1) showed that P. dactylifera can be differentiated from other Phoenix species and (2) enabled the quantification of patterns of shape differentiation in the genus Phoenix at different taxonomic, geographical and chronological levels. Date palm agrobiodiversity, partitioned in distinct morphotypes, appeared to be complex in terms of geographical structure. Allocation of archaeological seeds to different modern Phoenix forms and date palm morphotypes allowed us to reveal ancient forms consumed and/or exploited in Egypt and finally to determine spatial and temporal changes in agrobiodiversity. Main conclusions Based on the morphological diversity quantified in P. dactylifera and related species, we characterized ancestral seed shape features present in uncultivated populations. The geographical distribution pattern of seed shapes points to human dispersal routes that spread cultivation from one or more initial ‘domestication centres’. Finally, this work provides a powerful tool to identify ancient forms as demonstrated by the analysis of well‐preserved Egyptian archaeological seeds, dating from the 14th century bc to the 8th century ad . Results open new and fascinating perspectives on the investigation of the origins and chrono‐geographical fluctuation of date palm agrobiodiversity. 相似文献
17.
Martí D Miquel R Ziani K Gisbert R Ivorra MD Anselmi E Moreno L Villagrasa V Barettino D D'Ocon P 《American journal of physiology. Heart and circulatory physiology》2005,289(5):H1923-H1932
The mRNA levels for the three alpha1-adrenoceptor subtypes, alpha1A, alpha1B, and alpha1D, were quantified by real-time RT-PCR in arteries from Wistar rats. The alpha1D-adrenoceptor was prominent in both aorta (79.0%) and mesenteric artery (68.7%), alpha1A predominated in tail (61.7%) and small mesenteric artery (73.3%), and both alpha1A- and alpha1D-subtypes were expressed at similar levels in iliac artery. The mRNA levels of the alpha1B-subtype were a minority in all vessels (1.7-11.1%). Concentration-response curves of contraction in response to phenylephrine or relaxation in response to alpha1-adrenoceptor antagonists on maximal sustained contraction induced by phenylephrine were constructed from control vessels and vessels pretreated with 100 micromol/l chloroethylclonidine (CEC) for 30 min. The significant decrease in the phenylephrine potency observed after CEC treatment together with the inhibitory potency displayed by 8-{2-[4-(2-methoxyphenyl)-1-piperazinyl]-8-azaspiro (4,5) decane-7-dionedihydrochloride} (BMY-7378, an alpha1D-adrenoceptor antagonist) confirm the relevant role of alpha1D-adrenoceptors in aorta and iliac and proximal mesenteric arteries. The potency of 5-methylurapidil (an alpha1A-adrenoceptor antagonist) and the changes in the potency of both BMY-7378 and 5-methylurapidil after CEC treatment provided evidence of a mixed population of alpha1A- and alpha1D-adrenoceptors in iliac and distal mesenteric arteries. The low potency of prazosin (pIC50 < 9) as well as the high 5-methylurapidil potency in tail and small mesenteric arteries suggest the main role of alpha1A/alpha1L-adrenoceptors with minor participation of the alpha1D-subtype. The mRNA levels and CEC treatment corroborated this pattern and confirmed that the alpha1L-adrenoceptor could be a functional isoform of the alpha1A-subtype. 相似文献
18.
Andujar S Suvire F Berenguer I Cabedo N Marín P Moreno L Dolores Ivorra M Cortes D Enriz RD 《Journal of molecular modeling》2012,18(2):419-431
A molecular modeling study on 16 1-benzyl tetrahydroisoquinolines (BTHIQs) acting as dopaminergic ligands was carried out.
By combining molecular dynamics simulations with ab initio and density functional theory (DFT) calculations, a simple and
generally applicable procedure to evaluate the binding energies of BTHIQs interacting with the human dopamine D2 receptor
(D2 DR) is reported here, providing a clear picture of the binding interactions of BTHIQs from both structural and energetic
viewpoints. Molecular aspects of the binding interactions between BTHIQs and the D2 DR are discussed in detail. A significant
correlation between binding energies obtained from DFT calculations and experimental pKi values was obtained, predicting the potential dopaminergic effect of non-synthesized BTHIQs. 相似文献
19.
Montó F Oliver E Vicente D Rueda J Agüero J Almenar L Ivorra MD Barettino D D'Ocon P 《American journal of physiology. Heart and circulatory physiology》2012,303(3):H368-H376
Downregulation of β(1)- adrenergic receptors (β(1)-ARs) and increased expression/function of G-protein-coupled receptor kinase 2 (GRK2) have been observed in human heart failure, but changes in expression of other ARs and GRKs have not been established. Another unresolved question is the incidence of these compensatory mechanisms depending on heart failure etiology and treatment. To analyze these questions, we quantified the mRNA/protein expressions of six ARs (α(1A), α(1B), α(1D), β(1), β(2), and β(3)) and three GRKs (GRK2, GRK3, and GRK5) in left (LV) and right ventricle (RV) from four donors, 10 patients with ischemic cardiomyopathy (IC), 14 patients with dilated cardiomyopathy (DC), and 10 patients with nonischemic, nondilated cardiopathies (NINDC). We correlated the changes in the expressions of ARs and GRKs with clinical variables such as left ventricular ejection fraction (LVEF) and left ventricular end-systolic and left ventricular end-diastolic diameter (LVESD and LVEDD, respectively). The main findings were 1) the expression of the α(1A)-AR in the LV positively correlates with LVEF; 2) the expression of GRK3 and GRK5 inversely correlates with LVESD and LVEDD, supporting previous observations about a protective role for both kinases in failing hearts; and 3) β(1)-AR expression is downregulated in the LV and RV of IC, in the LV of DC, and in the RV of NINDC. This difference, better than an increased expression of GRK2 (not observed in IC), determines the lower LVEF in IC and DC vs. NINDC. 相似文献