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1.
Chemistry ; : e202401955, 2024 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-38860572

RESUMO

In response to the pressing global challenge of antibiotic resistance, time efficient design and synthesis of novel antibiotics are of immense need. Polycyclic polyprenylated acylphloroglucinols (PPAP) were previously reported to effectively combat a range of gram-positive bacteria. Although the exact mode of action is still not clear, we conceptualized a late-stage divergent synthesis approach to expand our natural product-based PPAP library by 30 additional entities to perform SAR studies against methicillin-resistant Staphylococcus aureus (MRSA). Although at this point only data from cellular assays are available and understanding of molecular drug-target interactions are lacking, the experimental data were used to generate 3D-QSAR models via an artificial intelligence training and to identify a common pharmacophore model. The experimentally validated QSAR model enabled the estimation of anti-MRSA activities of a virtual compound library consisting of more than 100.000 in-silico generated B PPAPs, out of which the 20 most promising candidates were synthesized. These novel PPAPs revealed significantly improved cellular activities against MRSA with growth inhibition down to nanomolar concentrations.

2.
Chemistry ; 24(37): 9295-9304, 2018 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-29726583

RESUMO

An unprecedented set of structurally diverse sulfonimidamides (47 compounds) has been prepared by various N-functionalization reactions of tertiary =NH sulfonimidamide 2 aa. These N-functionalization reactions of model compound 2 aa include arylation, alkylation, trifluoromethylation, cyanation, sulfonylation, alkoxycarbonylation (carbamate formation) and aminocarbonylation (urea formation). Small molecule X-ray analyses of selected N-functionalized products are reported. To gain further insight into the properties of sulfonimidamides relevant to medicinal chemistry, a variety of structurally diverse reaction products were tested in selected in vitro assays. The described N-functionalization reactions provide a short and efficient approach to structurally diverse sulfonimidamides which have been the subject of recent, growing interest in the life sciences.

3.
Chemistry ; 23(60): 15189-15193, 2017 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-28833686

RESUMO

Unprotected tertiary sulfonimidamides have been prepared in good to excellent yields in a one-pot transformation from tertiary sulfinamides through NH transfer. The reaction is mediated by commercially available (diacetoxyiodo)benzene and ammonium carbamate in methanol under convenient conditions. A wide range of functional groups are tolerated and initial results indicate that the NH transfer is stereospecific. A small molecule X-ray analysis of NH sulfonimidamide 2 a and its behavior in selected in vitro assays in comparison to the matched sulfonamide are also reported. This new reaction provides a safe, short and efficient approach to sulfonimidamides, which have been the subject of recent, growing interest in the life sciences.

4.
J Med Chem ; 66(22): 15061-15072, 2023 11 23.
Artigo em Inglês | MEDLINE | ID: mdl-37922400

RESUMO

Selective modulation of TRPC6 ion channels is a promising therapeutic approach for neurodegenerative diseases and depression. A significant advancement showcases the selective activation of TRPC6 through metalated type-B PPAP, termed PPAP53. This success stems from PPAP53's 1,3-diketone motif facilitating metal coordination. PPAP53 is water-soluble and as potent as hyperforin, the gold standard in this field. In contrast to type-A, type-B PPAPs offer advantages such as gram-scale synthesis, easy derivatization, and long-term stability. Our investigations reveal PPAP53 selectively binding to the C-terminus of TRPC6. Although cryoelectron microscopy has resolved the majority of the TRPC6 structure, the binding site in the C-terminus remained unresolved. To address this issue, we employed state-of-the-art artificial-intelligence-based protein structure prediction algorithms to predict the missing region. Our computational results, validated against experimental data, indicate that PPAP53 binds to the 777LLKL780-region of the C-terminus, thus providing critical insights into the binding mechanism of PPAP53.


Assuntos
Canais de Cátion TRPC , Sítios de Ligação , Microscopia Crioeletrônica , Canais de Cátion TRPC/efeitos dos fármacos , Canais de Cátion TRPC/metabolismo , Canal de Cátion TRPC6/efeitos dos fármacos , Floroglucinol/farmacologia , Compostos Policíclicos/farmacologia
5.
J Med Chem ; 66(22): 15073-15083, 2023 11 23.
Artigo em Inglês | MEDLINE | ID: mdl-37822271

RESUMO

Pre-SARS-CoV-2, tuberculosis was the leading cause of death by a single pathogen. Repetitive exposure of Mycobacterium tuberculosis(Mtb) supported the development of multidrug- and extensively drug-resistant strains, demanding novel drugs. Hyperforin, a natural type A polyprenylated polycyclic acylphloroglucinol from St. John's wort, exhibits antidepressant and antibacterial effects also against Mtb. Yet, Hyperforin's instability limits the utility in clinical practice. Here, we present photo- and bench-stable type B PPAPs with enhanced antimycobacterial efficacy. PPAP22 emerged as a lead compound, further improved as the sodium salt PPAP53, drastically enhancing solubility. PPAP53 inhibits the growth of virulent extracellular and intracellular Mtb without harming primary human macrophages. Importantly, PPAP53 is active against drug-resistant strains of Mtb. Furthermore, we analyzed the in vitro properties of PPAP53 in terms of CYP induction and the PXR interaction. Taken together, we introduce type PPAPs as a new class of antimycobacterial compounds, with remarkable antibacterial activity and favorable biophysical properties.


Assuntos
Mycobacterium tuberculosis , Tuberculose , Humanos , Terpenos/farmacologia , Antibacterianos/farmacologia , Antituberculosos/farmacologia
6.
Artigo em Inglês | MEDLINE | ID: mdl-36554474

RESUMO

BACKGROUND: the present research represents the first systematic review of the literature on the relation between happiness (i.e., subjective well-being, life satisfaction, positive affect) and family functioning in families with children aged 6-18 years. METHOD: relevant articles were systematically searched in three scientific databases (i.e., PsycInfo, Pubmed, and Web of Science) in June 2022. The databases were searched for original articles published after 1968 with the keywords "happiness" and "family functioning." RESULTS: of the 2683 records recovered, 124 original articles met the eligibility criteria and were included in the review. The articles were divided according to four emergent themes: (1) family dimensions and happiness; (2) global family functioning (i.e., family functioning, and family relationships), environmental variables, and happiness; (3) parental differences; (4) longitudinal studies. CONCLUSIONS: the results of the review provide evidence for a positive relation between happiness and family functioning, across different cultures and age groups: Family dimensions (e.g., cohesion, communication) were found to strongly predict children's and adolescents' happiness. Future studies should investigate the differences between fathers and mothers using multi-informant and mixed methods procedures and a longitudinal research approach. The implications of the findings for children's positive development are discussed.


Assuntos
Felicidade , Humanos , Criança , Adolescente , Estudos Longitudinais
7.
Nordisk Alkohol Nark ; 39(2): 134-145, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35757090

RESUMO

Aims: Research has underscored that an excessively intrusive parental style, defined as helicopter parenting, could be a risk factor for maladaptive behaviours in youth, including alcohol use and drug consumption. However, such at-risk behaviours have also been associated with low levels of parental involvement and warmth. Thus, the relationship between parental involvement and at-risk behaviours in adolescents is not clear. The purpose of the current study was to identify the relation between helicopter parenting and alcohol use in a sample of Italian youth. Design: The participants were 402 adolescents (233 female) between the ages of 14 and 19 years (M age= 17.20, SD = 1.66). Hierarchical multiple regression analyses were conducted to examine linear, quadratic, and exponential models and to verify which model best described the correlation. Results: The results showed a quadratic correlation between mothers' helicopter parenting and alcohol use, whereby higher and lower levels of mothers' helicopter parenting were associated with adolescents' alcohol use. Conclusions: The empirical data are essential for improving our understanding of the implications and potential outcomes of helicopter parenting during adolescence.

8.
J Sci Food Agric ; 91(6): 1128-34, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21328357

RESUMO

BACKGROUND: The present research analyses the contribution of some lipid antioxidants to the antioxidant activity of lipophilic extracts from basil by an electron paramagnetic resonance (EPR) study using the stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH). DPPH assay is considered an easy and accurate method with regard to measuring the antioxidant activity of plant extracts and EPR has already been employed to determine antioxidant activities of lipophilic plant extracts. RESULTS: Lipid extracts were obtained from basil grown hydroponically for 20 or 35 days from sowing and in soil for 35 days from sowing. Fast and slow rate constants were distinguishable in the decay kinetics of DPPH mixture added with lipid extract. Antioxidants with kinetics characterized by a fast decay rate were tocopherols and chlorophylls, whereas those characterized by a slow decay rate were carotenoids, among which were ß-carotene, lutein, ß-apo-8'-carotenal and zeaxanthin. The 20-day hydroponically grown sample, which showed higher contents of tocopherol, chlorophyll and carotenoid molecules, was the sample endowed with the higher content of fast lipophilic antioxidants (FLA) and slow lipophilic antioxidants (SLA). CONCLUSION: The three samples showed different compositions of FLA and SLA, giving rise to different decay kinetics. Despite the differences, in all samples tocopherol contributed about 0.3% to the bulk of FLA, whereas the figure for chlorophyll was about 40%, evidencing the relevant but little-studied role of chlorophyll as an antioxidant.


Assuntos
Antioxidantes/análise , Lipídeos/análise , Ocimum basilicum/química , Extratos Vegetais/química , Folhas de Planta/química , Antioxidantes/química , Compostos de Bifenilo/química , Carotenoides/análise , Carotenoides/química , Clorofila/análise , Clorofila/química , Espectroscopia de Ressonância de Spin Eletrônica , Sequestradores de Radicais Livres/análise , Sequestradores de Radicais Livres/química , Radicais Livres/química , Hidroponia , Cinética , Lipídeos/química , Ocimum basilicum/crescimento & desenvolvimento , Picratos/química , Tocoferóis/análise , Tocoferóis/química
9.
Physiol Plant ; 139(3): 256-68, 2010 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-20149130

RESUMO

Future environmental conditions will include elevated concentrations of salt in the soil and an elevated concentration of CO(2) in the atmosphere. Because these environmental changes will likely affect reactive oxygen species (ROS) formation and cellular antioxidant metabolism in opposite ways, we analyzed changes in cellular H(2)O(2) and non-enzymatic antioxidant metabolite [lipoic acid (LA), ascorbate (ASA), glutathione (GSH)] content induced by salt stress (0, 80, 160 or 240 mM NaCl) under ambient (350 micromol mol(-1)) or elevated (700 micromol mol(-1)) CO(2) concentrations in two barley cultivars (Hordeum vulgare L.) that differ in sensitivity to salinity (cv. Alpha is more sensitive than cv. Iranis). Under non-salinized conditions, elevated CO(2) increased LA content, while ASA and GSH content decreased. Under salinized conditions and ambient CO(2), ASA increased, while GSH and LA decreased. At 240 mM NaCl, H(2)O(2) increased in Alpha and decreased in Iranis. When salt stress was imposed at elevated CO(2), less oxidative stress and lower increases in ASA were detected, while LA was constitutively higher. The decrease in oxidative stress could have been because of less ROS formation or to a higher constitutive LA level, which might have improved regulation of ASA and GSH reductions. Iranis had a greater capacity to synthesize ASA de novo and had higher constitutive LA content than did Alpha. Therefore, we conclude that elevated CO(2) protects barley cultivars against oxidative damage. However, the magnitude of the positive effect is cultivar specific.


Assuntos
Dióxido de Carbono/metabolismo , Hordeum/metabolismo , Estresse Oxidativo , Salinidade , Ácido Tióctico/biossíntese , Ascorbato Peroxidases , Ácido Ascórbico/biossíntese , Glutationa/biossíntese , Glutationa Redutase/metabolismo , Peróxido de Hidrogênio/metabolismo , Oxirredução , Peroxidases/metabolismo
10.
Environ Sci Technol ; 44(16): 6403-8, 2010 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-20704241

RESUMO

The knowledge of the mechanisms that underlie metal complex uptake may lead to the development of new strategies for enhancing metal phytoextraction. As metals such as copper are actively taken up by roots, by inhibiting the proton driving force it is possible to obtain preliminary indications on the metal complex uptake mechanism. For this, Cu, EDDS, and Cu-EDDS uptake kinetics of Brassica carinata excised roots incubated in 30 and 150 microM solutions of either the metal, the chelant, and the complex were determined in the presence or not of the ATPase inhibitor vanadate. Following both Cu and CuEDDS treatments, metal uptake was negatively influenced by vanadate, whereas EDDS uptake did not, suggesting that Cu and the chelant did not enter the roots in their complexed form but by two different routes. The incubation in the same solutions of B. carinata intact plants showed that, differently from Cu, EDDS was largely translocated to shoots, but its low concentration resulted in a Cu to EDDS molar ratio ranging from 2 to 4 depending on metal complex concentration in the solution confirming that the uptake pathways of the two compounds were different.


Assuntos
Brassica/metabolismo , Cobre/metabolismo , Etilenodiaminas/metabolismo , Succinatos/metabolismo , Biodegradação Ambiental , Raízes de Plantas/metabolismo , Brotos de Planta/metabolismo , Soluções , Fatores de Tempo
11.
Physiol Plant ; 135(1): 29-42, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19121097

RESUMO

Changes in antioxidant metabolism because of the effect of salinity stress (0, 80, 160 or 240 mM NaCl) on protective enzyme activities under ambient (350 micromol mol(-1)) and elevated (700 micromol mol(-1)) CO(2) concentrations were investigated in two barley cultivars (Hordeum vulgare L., cvs Alpha and Iranis). Electrolyte leakage, peroxidation, antioxidant enzyme activities [superoxide dismutase (SOD), EC 1.15.1.1; ascorbate peroxidase (APX), EC 1.11.1.11; catalase (CAT), EC 1.11.1.6; dehydroascorbate reductase (DHAR), EC 1.8.5.1; monodehydroascorbate reductase (MDHAR), EC 1.6.5.4; glutathione reductase (GR), EC 1.6.4.2] and their isoenzymatic profiles were determined. Under salinity and ambient CO(2), upregulation of antioxidant enzymes such as SOD, APX, CAT, DHAR and GR occurred. However, this upregulation was not enough to counteract all ROS formation as both ion leakage and lipid peroxidation came into play. The higher constitutive SOD and CAT activities together with a higher contribution of Cu,Zn-SOD 1 detected in Iranis might possibly contribute and make this cultivar more salt-tolerant than Alpha. Elevated CO(2) alone had no effect on the constitutive levels of antioxidant enzymes in Iranis, whereas in Alpha it induced an increase in SOD, CAT and MDHAR together with a decrease of DHAR and GR. Under combined conditions of elevated CO(2) and salinity the oxidative damage recorded was lower, above all in Alpha, together with a lower upregulation of the antioxidant system. So it can be concluded that elevated CO(2) mitigates the oxidative stress caused by salinity, involving lower ROS generation and a better maintenance of redox homeostasis as a consequence of higher assimilation rates and lower photorespiration, being the response dependent on the cultivar analysed.


Assuntos
Antioxidantes/metabolismo , Dióxido de Carbono/farmacologia , Hordeum/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Cloreto de Sódio/farmacologia , Ascorbato Peroxidases , Catalase/metabolismo , Glutationa Redutase/metabolismo , Hordeum/enzimologia , Oxirredução , Peroxidases/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/enzimologia , Espécies Reativas de Oxigênio/metabolismo , Salinidade , Plantas Tolerantes a Sal/efeitos dos fármacos , Plantas Tolerantes a Sal/enzimologia , Especificidade da Espécie , Superóxido Dismutase/metabolismo
12.
Physiol Plant ; 132(4): 407-16, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18248509

RESUMO

Resurrection plants are able to dehydrate/rehydrate rapidly without cell damage by a mechanism, the understanding of which may be of ecological importance in the adaptation of crop plants to dry conditions. The o-diphenol oxidase in Ramonda serbica Pan. & Petrov, a rare resurrection plant of the Balkan Peninsula, was characterized in respect to different isoforms, preferable substrates and specific inhibitors. Two anionic isoforms with pI 4.6 and 4.7 were separated from turgid leaves. Three additional anionic isoforms (pI 5.1, 5.3 and 5.6) and three neutral isoforms (pI from 6.8 to 7.4) were induced in desiccated leaves. Based on apparent K(m) values, the affinity for reducing substrates decreased as follows: methyl catechol > chlorogenic acid > 3,4-dihydroxyphenylalanine > caffeic acid > pyrogallol. Polyphenol oxidase (PPO) activity was specifically sensitive to diethyldithiocarbamate and also inhibited by KCN, DTT and salicylic hydroxamic acid but with no inhibitory effect of Na3N. Plants were subjected to drought-to-near complete water loss (approximately 2% relative water content, RWC) and several fold higher PPO activity was detected in desiccated leaves. Ramonda leaves contain high levels of phenolics, which decreased during drought. Rehydration of dry leaves from 2% RWC to 95% RWC led to transient inhibition of PPO in the first few hours. Within a day, the levels completely recovered to those determined in desiccated leaves. The finding of desiccation-induced high activity of PPO and new isoforms, which were also present in rehydrated turgid leaves, indicates a substantial role for PPO in the adaptation mechanism of resurrection plants to desiccation and also to the oxidative stress during rehydration.


Assuntos
Catecol Oxidase/metabolismo , Magnoliopsida/enzimologia , Folhas de Planta/enzimologia , Dessecação , Eletroforese em Gel de Poliacrilamida , Focalização Isoelétrica
13.
J Agric Food Chem ; 56(9): 3391-7, 2008 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-18393430

RESUMO

The aim of this study was to assess whether the nutritional value of cherry tomato can be improved by irrigating plants with diluted seawater (12%; EC = 10 mS/cm in comparison with a control at EC = 4 mS/cm). Berries of cherry tomato cv. Naomi were analyzed at the red-ripe stage for the contents of NADPH and NADP+ as well as for the amounts of the main antioxidants, such as ascorbic acid, lipoic acid, tocopherols, and phenolic acids. As compared to the controls, the fruits of salt-treated plants showed a higher titratable acidity and a higher concentration of reducing sugars. The fruits picked from tomato plants irrigated with diluted seawater produced berries characterized by a higher nutritional value. Following salinity, berries showed higher amounts of vitamin C, vitamin E, dihydrolipoic acid, and chlorogenic acid. It was hypothesized that protocatechuic, vanillic, caffeic, and ferulic acids were utilized to counteract the damaging effects of salinity-induced oxidative stress, allowing tomato fruits to maintain a high reduced status even following salinization.


Assuntos
Agricultura/métodos , Frutas/química , Valor Nutritivo , Água do Mar , Solanum lycopersicum/crescimento & desenvolvimento , Ácido Ascórbico/análise , Ácidos Carboxílicos/análise , Frutas/crescimento & desenvolvimento , Solanum lycopersicum/química , NADP/análise , Tocoferóis/análise
14.
Phytochemistry ; 68(11): 1564-71, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17466344

RESUMO

In a long-term experiment bean (Phaseolus vulgaris L.) seedlings were grown for 18 days in hydroponics in either phosphate-sufficient (+P) or phosphate-deficient (-P) nutrient solutions. Phosphate deprivation halved the phosphorous content of roots. In plasma membrane (PM) fractions isolated from -P roots the phospholipid (PL) level was reduced from 35 to 21 mol%, while PL composition and degree of unsaturation were hardly altered. Digalactosyldiacylglycerol (DGDG) accumulated up to 26% of total PM lipids, replacing PL to a large extent. Molecular species and fatty acid compositions of DGDG in root PM were different compared to DGDG present in the -P plastids. In a short-term study, bean seedlings were grown for 18 days in hydroponics with a complete nutrient solution containing phosphate and then incubated in a -P medium for increasing time ranging from 1 up to 96 h. At the end of the starvation period phosphorous content of -P roots was reduced by 30% compared to +P ones. An activation of phospholipase D and phospholipase C was observed after 1 and 2h of phosphate deprivation, respectively. Maximal phosphatidic acid accumulation was detected after 4h of phosphate deprivation, when also DGDG started to accumulate in PM of bean roots. The fatty acid composition of PLD-derived phosphatidylbutanol resembled that of phosphatidylcholine.


Assuntos
Lipídeos de Membrana/metabolismo , Phaseolus/metabolismo , Fosfatos/metabolismo , Fosfolipases/metabolismo , Fracionamento Celular , Galactolipídeos/metabolismo , Phaseolus/enzimologia , Phaseolus/ultraestrutura , Raízes de Plantas/enzimologia , Raízes de Plantas/metabolismo , Raízes de Plantas/ultraestrutura , Fatores de Tempo
15.
J Plant Physiol ; 164(9): 1152-60, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16920221

RESUMO

Wheat seedlings (Triticum durum Desf.) were incubated in a solution containing 100 microM CuSO(4) for increasing time ranging from 1 min to 6h. Copper rapidly accumulated into the roots, and its amount increased significantly until 360 min. During the experiment, copper did not cause any lipid peroxidation and K(+) leakage. Up to 60 min of copper treatment the superoxide (O2(*-)) production in root apoplast decreased concomitantly with increase in superoxide dismutase (SOD) activity. In contrast, after 60 min of incubation, SOD decreased and this facilitated an increase in O2(*-) production. In the presence of the SOD inhibitor diethyldithiocarbamic acid, O2(*-) production was more than two times higher and showed a biphasic increase. Very high SOD activity in the apoplast, due to the presence of three different isozymes, one Mn-SOD and two CuZn-SODs, dismutated the radical giving rise, at least in part, to an increase in hydrogen peroxide. The highest value of H(2)O(2) was detected at 15 min, when peroxidase (POD) activity reached the lowest value. Root apoplast showed the presence of at least five different isoforms of PODs, whose pattern did not change during the entire treatment.


Assuntos
Cobre/farmacologia , Raízes de Plantas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Triticum/efeitos dos fármacos , Triticum/metabolismo , Peróxido de Hidrogênio , Potássio/metabolismo , Plântula/efeitos dos fármacos , Plântula/metabolismo , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismo
16.
Chemosphere ; 68(10): 1920-8, 2007 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-17418884

RESUMO

The potential of nine different species to grow in the presence of metals (As, Cd, Cu, Pb and Zn) and to accumulate them in the shoots was assessed for each metal separately by germination and root length tests, and successively by hydroponic experiments. Of the nine species tested, Brassica carinata was the species that accumulated the highest amounts of metals in shoots without suffering a significant biomass reduction. To further evaluate the potential of B. carinata for chelant-enhanced phytoextraction of a natural, multiply metal-polluted soil (As, Cd, Cu, Pb and Zn), both hydroponic and pot experiments were carried out with nitrilotriacetic acid (NTA) or (S,S)-ethylenediamine disuccinic acid (EDDS) as complexing agents. The hydroponic study with solutions containing the five metals together showed that accumulation of Cd, Cu, Pb and Zn in shoots was higher following EDDS addition compared to NTA. EDDS was more effective than NTA in desorbing Cu, Pb and Zn from the soil, whereas As and Cd were poorly extracted. B. carinata plants were grown for 4 weeks in the multiply metal-contaminated soil and then the soil was amended with 5 mmol kg(-1) NTA or EDDS. All plants were harvested 1 week after amendment. In comparison to NTA, EDDS was more effective in enhancing the concentrations of Cu, Pb and Zn in B. carinata shoots (2- to 4-fold increase compared to the control). One week after chelant addition, the DTPA-extractable metal concentrations in the polluted soil were lower in the EDDS treatment in comparison with the NTA amendment. Even though B. carinata showed a reduced growth and a relatively low metal uptake, it demonstrated the ability to survive and tolerate the presence of more metals simultaneously.


Assuntos
Biodegradação Ambiental , Brassica/metabolismo , Etilenodiaminas/química , Metais Pesados/metabolismo , Ácido Nitrilotriacético/química , Succinatos/química , Brassica/crescimento & desenvolvimento , Metais Pesados/química , Raízes de Plantas/crescimento & desenvolvimento , Poluentes do Solo/química , Poluentes do Solo/metabolismo
17.
Phytochemistry ; 67(12): 1232-42, 2006 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16765389

RESUMO

Wheat seedlings (Triticum durum Desf.) were incubated in 100muM Cu(2+) for different periods of time ranging from 1min up to 16h. Following metal addition a rapid intake of copper ions into the roots was observed. Cu(2+) induced an accumulation of both phosphatidic acid and phosphatidylbutanol within 1min of incubation, the latter indicating a very rapid induction of phospholipase D (PLD) activity. The highest PLD stimulation was detected after 2h from copper addition and decreased almost to the initial value at increasing times. Cycloheximide treatment of roots lowered phosphatidylbutanol accumulation because of a reduced PLD activity. The expression profile of a T. durum putative PLD-encoding gene showed a peak after 1h of treatment as well, indicating that enhanced gene expression contributed to the increase in PLD activity. In the absence of copper ions, roots treated with the G protein activator mastoparan showed increases in phosphatidic acid and phosphatidylbutanol similar to those detected with the metal. PLD activity was also stimulated by cholera toxin. Two putatively G protein alpha subunit encoding sequences were isolated and no significant differences in transcription activity following Cu(2+) addition were observed. In copper-treated roots an early production of superoxide generated both by total and membrane-bound NADPH oxidase occurred. The G protein inhibitor suramin as well as the PLD antagonist 1-butanol abolished copper-induced superoxide production.


Assuntos
Cobre/farmacologia , Fosfolipase D/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Triticum/efeitos dos fármacos , Triticum/metabolismo , Relação Dose-Resposta a Droga , Glicerofosfolipídeos/análise , Glicerofosfolipídeos/metabolismo , Ácidos Fosfatídicos/análise , Ácidos Fosfatídicos/metabolismo , Raízes de Plantas/enzimologia , Fatores de Tempo , Triticum/enzimologia
18.
Chemosphere ; 65(8): 1348-54, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16735050

RESUMO

Brassica juncea cv. 426308 was grown in soils containing 150 mg Cd(2+)kg(-1) soil. After 38 days, the soil was amended with two rates of citric acid or NTA (10 and 20 mmol kg(-1) soil). Control soil was not amended with chelates. Plants were harvested during growth, immediately before and seven days after chelate addition. Shoot composition of organic and phenolic acids and shoot Cd(2+) concentration were determined. Cadmium concentration remained constant during the growth and increased following NTA and citric acid amendments depending on chelate type and concentration. The highest increments in Cd(2+) were measured after the addition of NTA. Compared to the control, 10 and 20 NTA-treated plants showed two- and three-fold increases, respectively. At 150 mg Cd(2+)kg(-1) soil the amount of organic and phenolic acids in the leaves of B. juncea was always higher than that detected in the control. A direct correlation between organic acid concentration and cadmium content was detected both during growth and after chelate addition. On the contrary, the amount of phenols seemed to be correlated with the metal content only in non-amended and NTA-treated plants. The 10 and 20 citric acid additions caused 45% and 90% increases in shoot phenolic acids although cadmium content rose to a smaller extent. The inhibition of citrate synthase and the entrance of phosphoenolpyruvate in shikimate pathway leading to the formation of aromatic compounds might come into play. The increase in phenylalanine ammonialyase activity following citric acid amendments suggested this metabolic response.


Assuntos
Ácidos/metabolismo , Cádmio/farmacologia , Ácido Cítrico/farmacologia , Hidroxibenzoatos/metabolismo , Mostardeira/efeitos dos fármacos , Mostardeira/metabolismo , Ácido Nitrilotriacético/análogos & derivados , Ácido Nitrilotriacético/farmacologia , Cádmio/metabolismo , Ácido Cítrico/metabolismo , Fenilalanina Amônia-Liase/metabolismo , Brotos de Planta/efeitos dos fármacos , Brotos de Planta/metabolismo
19.
Biochim Biophys Acta ; 1564(2): 466-72, 2002 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-12175930

RESUMO

A response when wheat is grown in excess copper is an altered lipid composition of the root plasma membrane (PM). With detailed characterisation of the root PM lipid composition of the copper-treated plants as a basis, in the present study, model systems were used to gain a wider understanding about membrane behaviour, and the impact of a changed lipid composition.PMs from root cells of plants grown in excess copper (50 microM Cu(2+)) and control (0.3 microM Cu(2+)) were isolated using the two-phase partitioning method. Membrane vesicles were prepared of total lipids extracts from the isolated PMs, and also reference vesicles of phosphatidylcholine (PC). In a series of tests, the vesicle permeability for glucose and for protons was analysed. The vesicles show that copper stress reduced the permeability for glucose of the lipid bilayer barrier. When vesicles from stressed plants were modified by addition of lipids to resemble vesicles from control plants, the permeability for glucose was very similar to that of vesicles from control plants. The permeability for protons did not change upon stress. Electron paramagnetic resonance (EPR) of the lipid vesicles spin probed with n-doxylstearic acid (nDSA) was used to explore the lipid rotational freedom at different depth of the bilayer. The EPR measurements supported the permeability data, indicating that the copper stress resulted in more tightly packed bilayers of the PMs with reduced acyl chain motion.


Assuntos
Membrana Celular/química , Cobre , Lipídeos de Membrana/química , Triticum , Permeabilidade da Membrana Celular , Sulfato de Cobre , Espectroscopia de Ressonância de Spin Eletrônica , Lipídeos de Membrana/metabolismo , Estresse Oxidativo , Raízes de Plantas/química , Marcadores de Spin
20.
Physiol Plant ; 118(1): 21-28, 2003 May.
Artigo em Inglês | MEDLINE | ID: mdl-12702010

RESUMO

Raphanus sativus L. cv. Rimbo was grown for 10 days after emergence in hydroponic culture containing 0.12 (control), 5, 10 and 15 micro M copper. The seeds were germinated in the presence of the copper solution. The Cu contents increased with the treatment in both shoots and roots, maintaining in the roots a value eight- to ten-fold higher than in the shoots. With the treatment both shoots and roots underwent growth inhibition and an increase in the percentage of dry weight. Membrane damage and lipid peroxidation increased and glutathione was oxidized as the copper concentration increased, indicating an acceleration of oxidative processes. Control shoots had high contents of reduced glutathione and low contents of phytochelatin-SH whereas roots showed an opposite pattern, suggesting an utilization of reduced glutathione for phytochelatin synthesis. In both parts phytochelatin-SH content reached the maximum at 5 micro M copper and then decreased, reaching at 15 micro M copper the control value in the roots and a value five-fold higher than the control value in the shoots. The main phenolic acids represented in R. sativus were chlorogenic, vanillic, caffeic, siringic, p-coumaric and ferulic acids whereas the least represented were gallic, protocatechuic and p-hydroxybenzoic acids. The phenolic acids as well as the total and reduced ascorbate contents increased with the intensification of copper treatment. Notwithstanding these changes, total ascorbate remained 35% higher in the shoots than in the roots. The reduced ascorbate was thus able to replenish reducing equivalents to phenoxyl radicals thus explaining the increase in the phenolic compounds.

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