An efficient methodology for the purification of date palm peroxidase: Stability comparison with horseradish peroxidase (HRP)

In the present study, Peroxidase from date palm (Phoenix dactylifera) leaves was purified to homogeneity by three-step procedure including aqueous two-phase system, hydrophobic and Ion-exchange chromatography. The enzyme migrated as single band on SDS-PAGE giving molecular weight of 68?±?3?kDa. The purification factor for purified date palm peroxidase was 68 with high 41% yield. Enzymatic assays together with far-UV circular dichroism (CD), intrinsic and extrinsic fluorescence studies were carried out to monitor the structural stability of date palm and horseradish peroxidase (HRP) against various pH and temperatures. Activity measurements illustrated different pH stability for date palm and HRP. Both peroxidases are more susceptible to extreme acidic conditions as suggested by 4 & 15?nm red shift in date palm and HRP, respectively. Secondary structure analysis using far UV-CD exhibited predominance of α-helical (43.8%) structure. Also, pH induces loss in the secondary structure of date palm peroxidase. Thermal stability analysis revealed date palm peroxidase is more stable in comparison to HRP. In summary, date palm peroxidases could be promising enzymes for various applications where extreme pH and temperature is required.     

Purification and characterization of membrane-bound peroxidase from date palm leaves (Phoenix dactylifera L.)

Peroxidase from date palm (Phoenix dactylifera L.) leaves was purified to homogeneity and characterized biochemically. The enzyme purification included homogenization, extraction of pigments followed by consecutive chromatographies on DEAE-Sepharose and Superdex 200. The purification factor for purified date palm peroxidase was 17 with 5.8% yield. The purity was checked by SDS and native PAGE, which showed a single prominent band. The molecular weight of the enzyme was approximately 55 kDa as estimated by SDS–PAGE. The enzyme was characterized for thermal and pH stability, and kinetic parameters were determined using guaiacol as substrate. The optimum activity was between pH 5–6. The enzyme showed maximum activity at 55 °C and was fairly stable up to 75 °C, with 42% loss of activity. Date palm leaves peroxidase showed K_m values of 0.77 and 0.045 mM for guaiacol and H₂O₂, respectively. These properties suggest that this enzyme could be a promising tool for applications in different analytical determinations as well as for treatment of industrial effluents at low cost.     

Somatic embryogenesis and analysis of peroxidases inPhoenix dactylifera L

To determine some physiological parameters implicated in somatic embryogenesis in date palm (Phoenix dactylifera L.), peroxidases have been studied. Activated charcoal commonly used in date palm tissue culture as an essential antibrowning factor decreased cellular protein contents and peroxidase activities. During the first months of culture, the conventionally used medium (100 mg dm^?3 of 2,4-dichlorophenoxyacetic acid, 3 g dm^?3 charcoal) reduces 2 to 3 and 4 to 6 times protein contents and peroxidase activities, respectively, in comparison with the same one containing only 5 mg dm^?3 of 2,4-D and with or without 150 mg dm^?3 charcoal. In addition, the standard procedure decreased the embryogenic potential which is positively related to the intra- and extracellular (excreted into culture medium) peroxidase activities. In medium with embryogenic calli, extracellular peroxidase activity was three times as high as the activity determined in the same medium with non-embryogenic calli. There were two basic isoforms and four to five acidic bands characterizing the embryogenic calli. It can be suggested that peroxidases play a key role in somatic embryogenesis of date palm and the charcoal used at 3 g dm^?3 constitute a perturbating factor for this process.     

硫酸盐还原菌Desulfotomaculum reducens ZTS1厌氧降解昭通褐煤

[目的] 以云南昭通褐煤为研究对象,从矿井水富集产物中分离得到SRB菌株Desulfotomaculum reducens ZTS1厌氧降解褐煤,分析研究SRB菌株处理褐煤前后的物化性质变化。[方法] 采用工业和元素分析、XRD、FT-IR、SEM和低温液氮吸附法比较研究SRB厌氧降解褐煤前后矿物组成、有机官能团、表面形貌和孔隙结构变化。[结果] D.reducens ZTS1厌氧降解褐煤后灰分和挥发分略有降低,碳、氮和硫元素的含量降低,氧的含量增加,煤中硫代硫酸钠消失,FT-IR结果表明褐煤长链烃上的甲基和亚甲基团增多,游离羟基减少。煤表面粗糙度增加,小孔径的孔隙增多,孔径比表面积增大。[结论] D.reducens ZTS1可以厌氧降解昭通褐煤,厌氧降解后煤的物化性质发生变化。     

Biochemical changes in the germinating seeds ofTrigonella foenum graecum L. in relation tos-triazine herbicides

Thes-triazine herbicides studied (atrazine and simazine) inhibited the growth of the seedlings ofTrigonella foenum graecum L.(Viciaceae). These herbicides caused a decrease in the contents of total water soluble carbohydrates and reducing sugars. Pentose sugars increased in the cotyledons. The total protein and free amino acid contents were enhanced. The activity of peroxidase was inhibited in the cotyledons, but was enhanced in the seedling axes.     

Effects of Riyadh cement industry pollutions on some physiological and morphological factors of Datura innoxia Mill. plant

Cement factory emissions into air cause serious air pollution and affect the plant and animal life in the environment. Herein, we report the effects of cement industry emissions (O₃, SO₂ and NO₂) in air, as pollutants, at Riyadh City on Datura innoxia Mill. plant. Morphological characters including plant height, leaves area and number, fresh and dry weight of shoot and root systems of D. innoxia showed a significant reduction from their normal control plants as a response to exposure to pollutant emissions. Chlorophyll and carotenoid contents recorded reductions in values compared to control plant, and the lowest values of chlorophyll A, B, total chlorophyll, carotenoids and total pigments were 0.431, 0.169, 0.60, 0.343 and 0.943 mg/g respectively at a distance of 1–5 m from the cement factory in fruiting stage. These changes in values may be attributed to a probable deceleration of the biosynthetic process rather than degradation of pigments. Further D. innoxia showed a significant (P < 0.01) reduction in non-reducing and total sugars, protein and total lipid contents compared with the control plant. The root system recorded the lowest values of reducing sugars (0.350 mg/g f. wt.), non-reducing sugars (0.116 mg/g f. wt.), total sugars (0.466 mg/g f. wt.), protein content (0.931 mg/g f. wt.) and total lipids content (0.669 mg/g f. wt.) in fruiting stage at a distance of 1–5 m from the cement factory. The peroxidase activity of shoot and root systems of the studied plant was also significantly higher than those of control plant. Thus a highest value of (29.616 units/g f. wt.) peroxidase activity was recorded in vegetative stage of shoot system at a distance 1–5 m from the cement factory. Results of the study indicated that cement industry emission strongly influence the physiology and morphology of date palm D. innoxia which contribute date fruits, a staple food in the Arab world.     

Physicochemical and Functional Properties of Typical Tunisian Drink: Date Palm Sap (Phoenix dactylifera L.)

The present work aimed to study the physicochemical characteristics and the functional properties of the male date palm sap (Phoenix dactylifera L.). The surface properties at the air–water interface were studied on the basis of the drop volume method. Foaming properties (foam capacity and stability) were evaluated using bubbling method by optical and conductimetric measurements (foamscan). Composition analysis revealed a high sugar content (92.29% w/w dry matter basis) with dominance of sucrose. Sap contains also 5.14% w/w of proteins and 2.57% w/w of ash. Proteins are probably the source of the surface activity and the observed foam power. At higher contents of dry matter, lyophilized sap solutions showed Newtonian comportment and improved surface activity and foam properties. Results present some interesting functional properties that suggest to deepen research particularly in sap proteins.     

Purification and stability of peroxidase of African oil palm Elaies guineensis

In the previous work, after screening tropical plants (43 species) for peroxidase activity, high activity has been detected in leaves of some palms and especially African oil palm Elaeis guineensis. This palm is widely cultivated in Colombia and presents a promising source for the industrial production of peroxidase. The initial enzyme isolation included homogenization and extraction of pigments using aqueous two phase polymer system. Initially, traditional system, formed by polyethyleneglycol/K₂HPO₄, was used. The replacement of K₂HPO₄ with (NH₄)₂SO₄ allowed direct application of the salt phase with accumulated peroxidase on a Phenyl-Sepharose column. The final purification was carried out by liquid chromatography on Sephacryl S200 and DEAE-Toyopearl columns. The specific activity of the purified peroxidase measured toward guaiacol was 4300 units per mg of protein. The molecular weight and isoelectric point for palm peroxidase were 57.000 and 3.8, respectively. Palm peroxidase possesses uniquely high thermostability and is more stable in organic solvents than horseradish peroxidase is.     

Investigating the role of potassium and urea to control fruit drop and to improve fruit quality of “Dhakki” date palm

Fruit drop is a key issue with date palm cultivars that can be addressed with a variety of methods and strategies. Foliar application of macronutrients can be more effective in inhibiting fruit drop and improving the quality of date fruits. The current study was carried out to investigate the possible role of potassium (K) and urea to reduce fruit drop and improve the fruit quality of “Dhakki” date palm. It was conducted in a complete randomised block design with seven treatments and three replications at Pakistan's Agricultural Research Institute, Dera Ismail Khan. The treatments used were: (i) Control (distilled water spray); (ii) Potassium sulphate (K₂SO₄) at 1 %; (iii) K₂SO₄ at 1 % + Urea at 2 %; (iv) K₂SO₄ at 2 %; (v) K₂SO₄ at 2 % + Urea at 2 %; (vi) K₂SO₄ at 3 % and; (vii) K₂SO₄ at 3 % + Urea at 2 %. All the concentrations were sprayed at Kimri stage of fruit development during two consecutive growing seasons. Twenty-one date palms of equal size and age were chosen for the assessments to measure percent fruit drop and other physicochemical variables, including fruit length, fruit diameter, fruit weight, pulp percentage, yield/bundle, pH, total soluble solids (TSS), K content in fruit, and all sugars (percent) of harvested date fruit. The results revealed that bunch spray of K significantly affected all the parameters during both seasons. Application of K₂SO₄ alone and in combination with urea not only effectively reduced the fruit drop but also improved fruit quality in date where, K₂SO₄ applied at 2 % combined with urea was the best concentration in reducing fruit drop, enhancing other physicochemical attributes, and improving fruit quality of “Dhakki” date palm. This study may effectively contribute to reduce the fruit drop and enhance the fruit quality by using K and urea, enabling farmers to improve the date yield and increase economic growth.     

Preliminary Investigation on the Effect of Dietary Supplemental Biotin and Palm Kernel Oil on Blood,Liver and Kidney Lipids in Chicks

Abstract

A total of 480 day-old broiler chicks were used in two trials conducted to investigate the performance and lipid contents of blood, liver and kidneys of birds when fed varying levels of palm kernel oil (0% and 2%) and biotin (40, 80, 120, 160, 200 and 240 mcg/kg feed) in a 2 × 6 factorial experimental design. The results showed that blood, liver and kidney lipid concentrations were significantly affected by dietary biotin treatments. While total lipid, free fatty acid, triglyceride and cholesterol contents were negatively correlated with dietary biotin level, phospholipid concentrations were positively correlated. Biotin-deficient chicks had significantly higher total lipid, free fatty acid, triglyceride and cholesterol but lower phospholipid contents in their blood and the two organs. Supplementation of the diet with 2% palm kernel oil significantly elevated blood phospholipid concentration, but depressed the accumulation of the other lipid fractions in both organs and the blood of birds. Blood, liver and kidney cholesterol concentrations were not affected by 2% fat supplementation. Observation on the lipid parameters coupled with the results on feed utilisation appeared to suggest that a minimum of 120 mcg of the vitamin per kilograme of diet was required by broiler chicks for optimum performance.     

石油污染土壤自然衰减过程多环芳烃降解基因动态特征

新疆石油污染土壤中微生物多环芳烃(polycyclic aromatic hydrocarbons,PAHs)降解功能基因研究甚少,且环境因子和功能基因之间相关性仍不清楚。【目的】揭示新疆石油污染砂质土壤自然衰减过程中多环芳烃降解关键基因结构和变化规律。【方法】以新疆准东油田为研究区,分析同一采油区不同石油污染年限土壤理化因子和多环芳烃含量变化,采用扩增子测序研究石油自然衰减过程中多环芳烃降解酶基因结构变化规律,利用Mental检验探讨其环境驱动因子。【结果】石油污染时间1年和3年的土壤中有多项理化指标与背景土存在显著性差异,而污染5年土壤与背景土之间仅2项指标具有显著性差异,随石油自然衰减逐渐恢复至正常。石油污染1年的土壤中16种多环芳烃除苊烯和?以外,其余14种多环芳烃均高于石油污染3年和5年土壤,多环芳烃总量和含油率污染1年土壤均显著高于污染3年和5年的土壤,多环芳烃会在污染后短时间内迅速被降解。扩增子测序结果显示,萘双加氧酶基因分类操作单元(operational taxonomic units,OTUs)序列随污染年限延长逐渐增多;芳环羟化双加氧酶基因OTUs序列BLAST(...     

Peroxidases from the extreme dwarf tomato plant. Identification, isolation, and partial purification

Utilizing starch-gel electrophoresis, 12 discrete peroxidases were identified in purified extracts of the dwarf tomato shoot (Lycopersicon esculentum). Nine of the peroxidases moved toward the anode while 3 moved toward the cathode. In addition, a continuous peroxidase smear was separated from the above 12 peroxidases. This smear moved toward the anode and accounted for 50% of the total peroxidase activity in the crude extract.

Four of the major peroxidases were isolated and partially purified, using acetone and ammonium sulfate precipitations, preparative starch-gel electrophoresis and chromatography on DEAE and CM-cellulose.

     

Effects of climate change on economic feasibility of future date palm production: An integrated assessment in Iran

This study set out to build a model identifying areas where a positive Net Present Value (NPV) could be obtained from date palm (Phoenix dactylifera) using CLIMEX and six parameters including (a) suitable soil taxonomy and physicochemical soil properties, (b) slopes of less than 10°, (c) land uses suitable for date palm cultivation, (d) availability of roads, (e) availability of water, and (f) low risk of the lethal disease caused by Fusarium oxysporum f. spp. in the years 2030, 2050, 2070, and 2100 in Iran. Here, we utilized the A2 scenario and two global climate models (GCMs): CSIRO-Mk3.0 (CS) and MIROC-H (MR). Economic feasibility was estimated based on the assumption that the decision to plant date palms by landholders is motivated by a desire to maximize their return to land. Our results indicate that only 5450 km² of southern Iran will be highly profitable for cultivation of date palm, with NPV > 10,000, while profitable (with NPV between 4200 and 10,000) and moderately profitable (with NPV between 0 and 4200) areas would cover only 500 and 50 km², respectively, in future. A comparison of mean outputs from the two chosen GCMs and those of the economic and CLIMEX output combination indicates that only about 0.01% of areas from both GCMs will be highly economically viable for cultivation of date palm. In this study we ensure that the predictions become robust, rather than producing hypothetical findings, limited purely to publication.     

Clovamides; l-Dopa Conjugated with trans- and cis-Caffeic Acids in Red Clover (Trifolium pratense)

Selenium-independent glutathione peroxidase was purified from a cell-free extract of Mucor hiemalis by ammonium sulfate fractionation, column chromatographies on DEAE-Sephadex and hydroxylapatite, and gel filtration on Bio-Gel P-100. The purified enzyme was homogeneous on ultracentrifugation. The enzyme had a molecular weight of 45,000 and an isoelectric point of 5.2. The enzyme could reduce cumene hydroperoxide and t-butyl hydroperoxide, but could not reduce hydrogen peroxide. The enzyme was highly specific for glutathione as a hydrogen donor. Mucor glutathione peroxidase was proved to be different from mammalian selenium-dependent glutathione peroxidase I and selenium-independent glutathione peroxidase II in some physicochemical and enzymatic properties.     

Seed Viability and Biochemical Changes Associated with Accelerated Ageing in Dendrocalamus Strictus Seeds

Accelerated ageing of Dendrocalamus strictus Ness seeds at 42 ± 1°C and 100% relative humidity for 1 to 8 d was conducted. Seeds lost viability and changed their biochemical constituents. Reductions in the contents of sugars, starch, proteins and lipids were found. Decrease in the activity of the peroxidase as well as acid and alkaline phosphatase were also observed. Increase in total free amino acids content and the activity of amylase confirmed the degradation of seed reserves.     

CHARACTERIZATION OF MUCILAGE ON THE PROXIMAL CELLS OF YOUNG GAMETOPHYTES OF BOTRYCHIUM DISSECTUM (OPHIOGLOSSACEAE)

Young gametophytes of Botrychium dissectum produce a mucopolysaccharide coating on the external surface of the proximal cell. Scanning electron microscopy reveals deposition of the mucilage, which initially has a patchy distribution, in the shape of a thick triangular ring. Young gametophytes in the hydrated condition have a thin coating of mucilage over the other areas of the proximal cell wall. Histochemical staining indicates that the mucilage contains sugars with vicinal hydroxyl groups, carboxylated sugars, and small amounts of sulfated sugars. Protein and phenolic materials are also found in the mucilage. Lipids, β, 1-3 glucans and β,1-4 glucans are not present. Fluorescein labelled lectin binding shows the presence of terminal galactose and terminal fucose units. Germinating spores in the presence of the microtubule inhibitors CIPC (3-chloro-N-phenyl isporopyl carbamate) and griesiofulvin cause abnormal mucilage secretion. The inhibitor CIPC prevents mucilage secretion whereas griesiofulvin disrupts the pattern of deposition. Several functions of the mucilage are postulated.     

Enhancement of Defence Responses against Bayoud Disease by Treatment of Date Palm Seedlings with an Hypoaggressive Fusarium oxysporum Isolate

Pretreatment of date palm seedlings with an hypoaggressive Fusarium isolate (AHD) protected them partially from further infection by Fusarium oxysporum f.sp. albedinis (Foa), the Bayoud disease pathogen. No mortality occurred during 2–3 months of incubation in plants pretreated with AHD, as opposed to aggressive isolate (ZAG) inoculated controls where up to 100% mortality was observed 15–30 days after inoculation. Such protection involved biochemical interactions between the host plant and AHD since no direct competition or antagonism was revealed between AHD and ZAG. The examination of the accumulation of phenolics and peroxidase activity, two parameters previously reported to be involved in date palm resistance to Foa, indicated that the response to AHD was correlated with the ability of pretreated date palm tissues to establish a faster defence response in the roots of both susceptible and resistant cultivars. Plants pretreated with AHD accumulated higher amounts of phenolics, mainly non‐constitutive hydroxycinnamic acid derivatives, which play a crucial role in date palm defence against Foa, as previously described by our group. These compounds were accumulated along with the constitutive caffeoylshikimic acids. A faster induction of peroxidase activity in response to Foa was also recorded in plants pretreated with AHD. Given the multi‐component nature of these induced responses, AHD could be part of integrated disease management strategies for a sustainable control of the palm tree Bayoud disease.     

Pyrolytic and hydrothermal carbonization of date palm leaflets: Characteristics and ecotoxicological effects on seed germination of lettuce

Biochar has vital importance as soil additives due to its characteristics, which are responsible for alleviating environmental problems and climate change. These additives should be evaluated to understand their physico-chemical properties and their ecotoxicological effects on plant growth. Therefore, this study aimed to (i) distinguish the properties of biochar produced from date palm and its derivative hydrochar, and (ii) investigate their ecotoxicological effects. Specifically, the biochar and hydrochar were produced from date palm leaflets by pyrolysis and hydrothermal carbonization, respectively. The produced chars were evaluated for their characteristics before and after water washing, and for their ecotoxicological effects on seed germination of lettuce (Lactuca sativa L). The results show that water washing lowered biochar’s pH and increased hydrochar’s pH. Moreover, water washing of hydrochar caused a significant reduction in the total content of essential elements such as Ca, Mg, Mn, and Zn. Lettuce germination was significantly inhibited to 20% by hydrochar, whereas biochar enhanced lettuce growth by increasing shoot length (by 51%) and dry biomass (by 114%). Hydrochar toxicity was correlated (R > 0.95 at p = 0.05) with high contents of total polyaromatic hydrocarbons (98.8 mg kg⁻¹). Pre-treatment and assessment of hydrochar should be taken into account prior to application as a soil amendment.     

Degradation of seed mucilage by soil microflora promotes early seedling growth of a desert sand dune plant

In contrast to the extensive understanding of seed mucilage biosynthesis, much less is known about how mucilage is biodegraded and what role it plays in the soil where seeds germinate. We studied seed mucilage biodegradation by a natural microbial community. High‐performance anion‐exchange chromatography (HPAEC) was used to determine monosaccharide composition in achene mucilage of Artemisia sphaerocephala. Mucilage degradation by the soil microbial community from natural habitats was examined by monosaccharide utilization tests using Biolog plates, chemical assays and phospholipid fatty acid (PLFA) analysis. Glucose (29.4%), mannose (20.3%) and arabinose (19.5%) were found to be the main components of achene mucilage. The mucilage was biodegraded to CO₂ and soluble sugars, and an increase in soil microbial biomass was observed during biodegradation. Fluorescence microscopy showed the presence of mucilage (or its derivatives) in seedling tissues after growth with fluorescein isothiocyanate (FITC)‐labelled mucilage. The biodegradation also promoted early seedling growth in barren sand dunes, which was associated with a large soil microbial community that supplies substances promoting seedling establishment. We conclude that biodegradation of seed mucilage can play an ecologically important role in the life cycles of plants especially in harsh desert environments to which A. sphaerocephala is well‐adapted.