Effects of varying dietary docosahexaenoic acid levels on growth,proximate composition and tissue fatty acid profile of juvenile silver pomfrets,Pampus argenteus (Euphrasen, 1788)

This study investigated the effects of varying dietary levels of decosahexaenoic acid (DHA) on growth performance, proximate composition and whole body fatty acid profiles of juvenile silver pomfret, Pampus argenteus. Triplicate groups of fish (30.55 ± 0.08 g) were fed diets containing 5.2%, 9.31% and 13.38% DHA (% of total fatty acids) or 0.85%, 1.52% and 2.18% DHA on dry diet weight for diets 1, 2 and 3 respectively. Survival was not affected by dietary DHA levels. The growth performance and feed utilization parameters of fish fed diets 2 and 3 were significantly (P < 0.05) higher than those fed diet 1, although these parameters in diets 2 and 3 did not differ significantly (P > 0.05). Whole body lipid and fatty acid profiles were influenced by dietary DHA levels. Significantly higher n‐3 fatty acids particularly DHA, DHA:EPA(eicosapentaenoic acid) ratios and n‐3:n‐6 ratios were observed in fish fed diets 2 and 3 compared to those fed diet 1. Better growth performance and higher whole body DHA:EPA (2.31, 2.29) ratios and n‐3:n‐6 ratios (2.17, 2.12) observed in fish fed diets 2 and 3, respectively, suggests that silver pomfret juveniles have a higher requirement for n‐3 fatty acids, notably DHA for optimum growth and survival.     

Recognition of betaine as an inhibitor of lipopolysaccharide-induced nitric oxide production in activated microglial cells

Background: Neuroinflammation, as a major outcome of microglia activation, is an important factor for progression of neurodegenerative disorders including Alzheimer''s disease and Parkinson''s disease. Microglial cells, as the first-line defense in the central nervous system, act as a source of neurotoxic factors such as nitric oxide (NO), a free radical which is involved in neuronal cell death. The aim of this study was to inhibit production of NO in activated microglial cells in order to decrease neurological damages that threat the central nervous system. Methods: An in vitro model of a newborn rat brain cell culture was used to examine the effect of betaine on the release of NO induced by lipopolysaccharide (LPS). Briefly, primary microglial cells were stimulated by LPS and after 2 minutes, they were treated by different concentrations of betaine. The production of NO was assessed by the Griess assay while cell viability was determined by the MTT assay. Results: Our investigations indicated that LPS-induced NO release was attenuated by betaine, suggesting that this compound might inhibit NO release. The effects of betaine on NO production in activated microglial cells after 24 h were "dose-dependent". It means that microglial cells which were treated with higher concentrations of betaine, released lower amounts of NO. Also our observations showed that betaine compound has no toxic effect on microglial cells. Conclusion: Betaine has an inhibitory effect on NO release in activated microglial cells and may be an effective therapeutic component to control neurological disorders.Key Words: Betaine, Lipopolysaccharides (LPS), Nitric oxide (NO), Microglia     

Assessment of resistance to bacterial wilt incited by Ralstonia solanacearum in tomato germplasm

Journal of Plant Diseases and Protection - Bacterial wilt incited by Ralstonia solanacearum has been found the most damaging and widespread diseases of tomato throughout the world and causes heavy...     

Moringa oleifera Lam. leaf extract as bioregulator for improving growth of maize under mercuric chloride stress

The contamination of agriculture soils with heavy metals is increasing due to both natural and anthropogenic activities. This has resulted in lowering the yield and quality of agriculture crops. The aim of the present investigation was to determine the effect of Moringa oleifera (M. oleifera) aqueous leaf extract (MALE) on growth and Hg phytoextraction potential of maize cv. Azam under mercuric chloride (HgCl₂)-induced stress. Soil was contaminated with different concentrations of HgCl₂ (1 and 0.5?mg/kg). The MALE was applied at 5% and 2.5% as seed soaking prior to sowing of seeds in the pots. The M. oleifera leaf was a good source of macronutrients (Na, K, Ca and Mg) and micronutrients (Fe, Zn, Mn, Co and Ni) as well as natural phenolics. The induced HgCl₂ stress significantly reduced seed germination (%), shoot dry weight, root dry weight, chlorophyll content and carotenoids content. The HgCl₂-induced stress was associated with accumulation of phenolics and Hg in roots. The accumulation of Hg in roots was significantly correlated with phenolics content (r?=?.8007, p?=?.000). The exogenous application of MALE significantly ameliorated adverse effects of HgCl₂ stress on maize plants. The accumulation of Hg in roots was significantly increased by MALE. It is inferred from findings of the present investigation that MALE served as bioregulator and can be applied to reduce adverse effects of HgCl₂ on maize. Moreover, MALE can enhance the Hg phytoremediation potential of maize.     

Effects of salicylic acid on growth and accumulation of phenolics in Zea mays L. under drought stress

The accumulation of total soluble and cell wall-bound phenolics and total soluble proteins in Zea mays plants exposed to drought stress and foliar spray of salicylic acid (SA) at 10^?4?mol/L and 10^?5?mol/L was investigated. Drought stress was imposed at the four-leaf stage for 10 days (30–35% field capacity). Dehydration of maize leaves was accompanied by the accumulation of both total soluble and cell wall-bound phenolics, reduction in leaf relative water content (LRWC), and shoot and root growth attributes. Foliar spraying of SA further augmented the content of total soluble and cell wall-bound phenolics and total soluble proteins content under drought stress. SA ameliorated the adverse effects of drought stress on LRWC, shoot fresh weight, shoot dry weight, root fresh weight, root dry weight, root length and root area. The accumulation of both soluble and cell wall-bound phenolics by foliar spray of SA may be a mechanism related to SA-induced drought stress tolerance in maize. It was concluded that foliar spraying of SA at 10^?5?mol/L can be highly economical and effective for modifying the effects of drought stress on maize at the four-leaf stage.     

Separation of Ag(I) Ions from Lepidium draba L. Plant and Water and Standard Samples by Carrier Element-Free Coprecipitation Method Prior to their Flame Atomic Absorption Spectrometric Determination

In this work, silver iodide (Ag(I)) ions were separated via the carrier element-free coprecipitation (CEFC) method using an organic coprecipitating agent, 1,6-diamino-4-(4-chlornphenyl)-2-oxo-1,2-dihydropyridine-3,5-dicarbonitrile [DCODD] prior to its determination by ?ame atomic absorption spectrometry (FAAS). Analytical parameters including pH of aqueous solution, amount of DCODD, standing time, centrifugation rate and time, and sample volume were studied and optimized. Under the best experimental conditions, it was found that extraction can be performed from the sample volume of 500.0 for silver ion (preconcentration factor of 100.0). Linearity was maintained between 0.006 and 1.50 µg.mL^?1 for silver. Detection limit for silver based on 3Sb was 1.60 ng.mL^?1. The relative standard deviation of eight replicate measurements of 0.20 µg.mL^?1of silver was 2.10%. Finally, the developed method was successfully applied to extraction and determination of the silver ions in the Lepidium draba L plant, water and standard samples and satisfactory results were obtained.     

Phosphorus amendment decreased cadmium (Cd) uptake and ameliorates chlorophyll contents,gas exchange attributes,antioxidants, and mineral nutrients in wheat (Triticum aestivum L.) under Cd stress

A 28-day pot (sand culture) experiment was carried to evaluate the effects of phosphorus (P) application in alleviating Cd phytotoxicity in wheat plants. Different levels of P (0, 10, and 20 kg ha^?1) were applied without and with 100 µM Cd. The results showed that 100 µM Cd concentration decreased plant biomass, chlorophyll contents, gas exchange attributes, and mineral nutrients in wheat plants. Cadmium stress increased tissue Cd and H₂O₂ concentrations. The activities of superoxide dismutases (SOD), peroxidase (POD) enzymes, increased while the activities of catalase (CAT), ascorbic acid (AsA), α-tocopherol, and phenolics decreased under Cd stress. Phosphorus supply increased shoot biomass, leaf area, photosynthetic pigments, and mineral nutrients and decreased Cd and H₂O₂ concentrations in shoots. Phosphorus application improved antioxidant enzyme activities and gas exchange attributes which emerged as an important mechanism of Cd tolerance in wheat. We conclude that P application contributes to decreased Cd concentrations in wheat shoots and increased gas exchange attributes and antioxidant enzymes and could be implemented in a general scheme aiming at controlling Cd concentrations in wheat for sustained production of this important grain crop.     

Synthesis of poly(hydroxamic acid) ligand from polymer grafted khaya cellulose for transition metals extraction

A cellulose-graft-poly(methyl acrylate) was synthesized by free radical initiating process and the ester functional groups were converted into the hydroxamic acid ligand. The intermediate and final products are characterized by FT-IR, FE-SEM, HR-TEM and XPS technique. The pH of the solution acts as a key factor in achieving optical color signals of metalcomplexation. The reflectance spectra of the [Cu-ligand]n+ complex was found to be a highest absorbance at 99.8 % at pH 6 and it was increased upon increasing of Cu²⁺ ion concentrations and a broad peak at 700 nm was observed which indicated the charge transfer (π-π transition) metals-Cu complex. The adsorption capacity of copper was found to be superior (336 mg g^?1) rather than other transition metals such as Fe³⁺, Co³⁺, Cr³⁺, Ni²⁺, Mn²⁺ and Zn²⁺ were 310, 295, 288, 250, 248 and 225 mg g^-1, respectively at pH 6. The experimental data of all metal ions fitted significantly with the pseudo-second-order rate equation. The transition metal ions sorption onto ligand were well fitted with the Langmuir isotherm model (R²>0.99), which suggested that the cellulose-based adsorbent known as poly(hydroxamic acid) ligand surface is homogenous and monolayer. The reusability of the poly(hydroxamic acid) ligand was checked by the sorption/desorption process up to ten cycles without any significant loss in its original sensing and removal performances.     

Effect of elevated CO2 on soil N dynamics in a temperate grassland soil

The response of terrestrial ecosystems to elevated atmospheric CO₂ is related to the availability of other nutrients and in particular to nitrogen (N). Here we present results on soil N transformation dynamics from a N-limited temperate grassland that had been under Free Air CO₂ Enrichment (FACE) for six years. A ¹⁵N labelling laboratory study (i.e. in absence of plant N uptake) was carried out to identify the effect of elevated CO₂ on gross soil N transformations. The simultaneous gross N transformation rates in the soil were analyzed with a ¹⁵N tracing model which considered mineralization of two soil organic matter (SOM) pools, included nitrification from NH₄⁺ and from organic-N to NO₃⁻ and analysed the rate of dissimilatory NO₃⁻ reduction to NH₄⁺ (DNRA). Results indicate that the mineralization of labile organic-N became more important under elevated CO₂. At the same time the gross rate of NH₄⁺ immobilization increased by 20%, while NH₄⁺ oxidation to NO₃⁻ was reduced by 25% under elevated CO₂. The NO₃⁻ dynamics under elevated CO₂ were characterized by a 52% increase in NO₃⁻ immobilization and a 141% increase in the DNRA rate, while NO₃⁻ production via heterotrophic nitrification was reduced to almost zero. The increased turnover of the NH₄⁺ pool, combined with the increased DNRA rate provided an indication that the available N in the grassland soil may gradually shift towards NH₄⁺ under elevated CO₂. The advantage of such a shift is that NH₄⁺ is less prone to N losses, which may increase the N retention and N use efficiency in the grassland ecosystem under elevated CO₂.