Effect of water deficit on Argan tree seedlings (Argania spinosa L. Skeels): Morphological and physiological aspect

The Argan tree, Argania spinosa L., Skeels, is an endemic species in North-West Africa perfectly adapted to aridity and drought. It is in this context that we studied the physiological impact of water deficit on the Argan tree seedlings for eight weeks at a field capacity of 30%. The obtained results reveal that the stressed seedlings manifested by the strategy of the root elongation from the second week, the roots reached 31 cm compared with 15 cm of the control. However, the seedlings showed severe dehydration of 41% in leaves and 45% in roots. Besides, the content of chlorophyll pigments has relatively decreased from the second week, a slight yellowing and leaf drop was observed. The seedlings have accumulated proteins in a very significant way in leaves (from 25 to 107 mg.g-1 by fresh weight) and (from 23 to 90 mg.g-1 by fresh weight) in roots. Proline was also accumulated; the content was 4 and 2 μg.g-1 by fresh weight respectively in leaves and roots compared with 1.3 and 1.1 μg.g-1 1 by fresh weight in control respectively. The accumulation of the protein and proline is higher in leaves than in roots. The content of malondialdehyde was higher in leaves than in roots. This increase is significantly related to the prolongation of the stress period from the second week. The enzymatic activity of peroxidase is in relative increase according to the duration of the water stress applied in both leaves and roots. We deduce from these results that Argan seedlings possess the characteristic of xeropyhte that tolerate aridity. Key words: Argania spinosa,  drought stress,  proline,  chlorophylls,  proteins

Neuroprotective effect of wormwood against lead exposure

<b>Background</b> : Lead poisoning is a potential factor in brain damage, neurochemical dysfunction and severe behavioral problems. Considering this effect, our study was carried out to investigate the effects of wormwood to restore enzymes activities, lipid peroxidation and behavioral changes induced by lead. <b>Methods</b> : Thirty Wistar rats were divided into five groups (<i>n</i> = 6 in each group): three groups exposed to 750 ppm of lead acetate in the drinking water for 11 weeks and two groups as control. Aqueous wormwood extract (200 mg/kg body weight) was administrated to intoxicated (Pb(-)&#x002B;A.AB) and control groups (A.AB) for four supplemental weeks. Activities of acetylcholinesterase (AchE), monoamine oxidase (MAO) and thiobarbituric acid-reactive substances (TBARS) level were determined in the hypothalamus, hippocampus, cortex and striatum of male rats and the grooming and locomotors activity were defined in all groups. Results: The intoxicated group (Pb) has a significantly increased TBARS value compared with the control in all <b>brain</b> regions (<i>P</i> &lt; 0.05) and, after treatment with the wormwood extract, a significant reduction was noted. The enzyme activity decreased significantly (<i>P</i> &lt; 0.05) in the Pb group compared with the control, essentially for the hippocampus (AchE: -57&#x0025;, MAO: -41&#x0025;) and the striatum (AchE: -43&#x0025;, MAO: -51&#x0025;). After wormwood extract administration, the AchE and MAO activity were significantly increased in all brain regions compared with the Pb group (<i>P</i> &lt; 0.05). The behavioral test (locomotors and grooming test) indicates a significant hyperactivity in the Pb group compared with the control group. After treatment with wormwood extract, the Pb(-)&#x002B;A.Ab indicates a lower activity compared with Pb. <b>Conclusion</b> : These data suggest that wormwood extract may play a very useful role in reduction of the neurotoxicological damage induced by lead

Prophylactic effects of Wormwood on lipid peroxidation in an animal model of lead intoxication

The ability of Wormwood (Artemisia absinthium L.) extract (A.Ab) to restore membrane-bound enzymes like Na+-K+-ATPase, Ca++-ATPase, Mg++-ATPase, and oxidative damage induced by lead were investigated. Rats were exposed to lead acetate (750 ppm) for 11-weeks and treated during 4-weeks with A.Ab. Lipid levels, ATPase activity, thiobarbituric acid reactive substances (TBARS), and proteins carbonyl were estimated. In liver and kidney, lead acetate inhibited membrane-bound enzymes and increased (P < 0.05) the levels of cholesterol, triglycerides, free fatty acids, phospholipids, TBARS, and carbonyl proteins. After 4 weeks, the intoxicated group who received A.Ab showed a significant reduction in TBARS and carbonyl levels in liver and kidney compared to group exposed to lead. A.Ab restored the levels of membrane-bound enzymes and lipid levels to near normal. These results indicate that aqueous Wormwood extract had a significant antioxidant activity and protect liver and kidney from the lead-induced toxicity

The fourth transmembrane segment of the Na,K-ATPase alpha subunit: a systematic mutagenesis study.

The Na,K-ATPase is a major ion-motive ATPase of the P-type family responsible for many aspects of cellular homeostasis. To determine the structure of the pathway for cations across the transmembrane portion of the Na,K-ATPase, we mutated 24 residues of the fourth transmembrane segment into cysteine and studied their function and accessibility by exposure to the sulfhydryl reagent 2-aminoethyl-methanethiosulfonate. Accessibility was also examined after treatment with palytoxin, which transforms the Na,K-pump into a cation channel. Of the 24 tested cysteine mutants, seven had no or a much reduced transport function. In particular cysteine mutants of the highly conserved "PEG" motif had a strongly reduced activity. However, most of the non-functional mutants could still be transformed by palytoxin as well as all of the functional mutants. Accessibility, determined as a 2-aminoethyl-methanethiosulfonate-induced reduction of the transport activity or as inhibition of the membrane conductance after palytoxin treatment, was observed for the following positions: Phe(323), Ile(322), Gly(326), Ala(330), Pro(333), Glu(334), and Gly(335). In accordance with a structural model of the Na,K-ATPase obtained by homology modeling with the two published structures of sarcoplasmic and endoplasmic reticulum calcium ATPase (Protein Data Bank codes 1EUL and 1IWO), the results suggest the presence of a cation pathway along the side of the fourth transmembrane segment that faces the space between transmembrane segments 5 and 6. The phenylalanine residue in position 323 has a critical position at the outer mouth of the cation pathway. The residues thought to form the cation binding site II ((333)PEGL) are also part of the accessible wall of the cation pathway opened by palytoxin through the Na,K-pump

Lead Induced Oxidative Stress and Development Change on Coriandrum sativum

Lead (Pb) is ubiquitous pollutant in environment which causes many toxic effects, at high and low dose, Lead makes disruptions at all plants by reduction its growth and development of aerial parts and roots, however in Coriandrum the mechanism it not well known. In this study, assessing the capacity of lead to induce a dysfunctioning in development of roots and aerial parts at different concentrations after 21 day and 40 days, biochemical parameters of oxidative stress and morphological change on&nbsp;Coriandrum sativum&nbsp;was studied in the present investigation. The seeds were sprayed with a solution containing lead to different concentrations for 40 days with six lead levels (0 as control, 500, 1000, 1500, 2000, 2500 and 3000 mg.l-1). The soil used was characterized and parameters such as growth, oxidative damage markers (lipid peroxidation, proline, chlorophyll and hydrogen peroxide contents) were investigated. The results show that there is no change in properties of roots, sheets and stalks indicate that chlorophyll and carotenoid concentration were significantly decreased at 3000 mg.l-1&nbsp;Pb than control. Lipid peroxidation and H2O2levels were increased at the dose of 2500 and 3000 mg l-1&nbsp;compared to control treatment; no difference was noted between 500 mg.l-1&nbsp;and control in all part in plant. Morphological studies show that the group exposed to 3000 mg.l-1&nbsp;of lead shows a very important development of the tissues of roots and stems compared to control and to the group exposed to 500 mg.l-1&nbsp;of Pb. changes in morphological structure and non-enzymatic antioxidants have shown that lead exposure causes a significant perturbation on&nbsp;Coriandrum sativum&nbsp;Linn seedlings affecting biochemical and physiological processes. &nbsp