Gaseous emissions of nitrogen and carbon from urban vegetable gardens in Bobo‐Dioulasso,Burkina Faso

Urban and peri‐urban agriculture (UPA) is an important livelihood strategy for the urban poor in sub‐Saharan Africa and contributes to meeting increasing food demands in the rapidly growing cities. Although in recent years many research activities have been geared towards enhancing the productivity of this land‐use system, little is known about turnover processes and nutrient efficiency of UPA. The aim of our study therefore was to determine horizontal fluxes of N, P, K, and C as well as gaseous N and C emissions in urban vegetable gardens of Bobo‐Dioulasso, Burkina Faso. Two gardens referred to as “Kodéni” and “Kuinima” were selected as representative for urban and peri‐urban systems classified as: (1) “commercial gardening + field crops and livestock system” and (2) “commercial gardening and semicommercial field crop system”, respectively. A nutrient‐balance approach was used to monitor matter fluxes from March 2008 to March 2009 in both gardens. Ammonia (NH₃), nitrous oxide (N₂O) and carbon dioxide (CO₂) emissions from the respective soils were measured during the coolest and the hottest period of the day using a closed‐chamber system. Annual partial balances amounted to 2056 kg N ha^–1, 615 kg P ha^–1, 1864 kg K ha^–1, and 33 893 kg C ha^–1 at Kodéni and to 1752 kg N ha^–1, 446 kg P ha^–1, 1643 kg K ha^–1, and 21 021 kg C ha^–1 at Kuinima. Emission rates were highest during the hot midday hours with peaks after fertilizer applications when fluxes of up to 1140 g NH₃‐N ha^–1 h^–1, 154 g N₂O‐N ha^–1 h^–1, 12 993 g CO₂‐C ha^–1 h^–1 were recorded for Kodéni and Kuinima. Estimated annual gaseous N (NH₃‐N + N₂O‐N) and C (CO₂‐C + CH₄‐C) losses reached 419 kg N ha^–1 and 35 862 kg C ha^–1 at Kodéni and 347 kg N ha^–1 and 22 364 kg C ha^–1 at Kuinima. For both gardens, this represented 20% and 106% of the N and C surpluses, respectively. Emissions of NH₃, largely emitted after surface application of manure and mineral fertilizers, accounted for 73% and 77% of total estimated N losses for Kodéni and Kuinima. To mitigate N losses nutrient‐management practices in UPA vegetable production of Bobo‐Dioulasso would greatly benefit from better synchronizing nutrient‐input rates with crop demands.     

Polydopamine Nanoparticles as a New and Highly Selective Biosorbent for the Removal of Copper (II) Ions from Aqueous Solutions

The adsorption and desorption of copper (II) ions from aqueous solutions were investigated using polydopamine (PD) nanoparticles. The nanoscale PD nanoparticles with mean diameter of 75?nm as adsorbent were synthesized from alkaline solution of dopamine and confirmed using scanning electron microscopy and X-ray diffraction analysis. The effects of pH (2?C6), adsorbent dosage (0.2?C0.8?g?L^?1), temperature (298?C323?K), initial concentration (20?C100?mg?L^?1), foreign ions (Zn²⁺, Ni²⁺, Cd²⁺, Fe²⁺, and Ag⁺), and contact time (0?C360?min) on adsorption of copper ions were investigated through batch experiments. The isotherm adsorption data were well described by the Langmuir isotherm model. The maximum uptake capacity of Cu²⁺ ions onto PD nanoparticles was found to 34.4?mg/g. The kinetic data were fitted well to pseudo-second-order model. Moreover, the thermodynamic parameters of the adsorption (the Gibbs free energy, entropy, and enthalpy) were studied.     

Physiological and histopathological assessments of the susceptibility of different tomato (Solanum lycopersicum) cultivars to early blight disease

European Journal of Plant Pathology - The current research aims to evaluate the susceptibility of the tomato of the tomato (Solanum lycopersicum) cultivars 65,015 (CV1), Basma (CV2), Dalia (CV3),...     

Antibacterial effect of carbon nanofibers containing Ag nanoparticles

Silver nanoparticles imbedded in polyacrylonitrile (PAN) nanofibers and converted into carbon nanofibers by calcination was obtained in a simple three-step process. The first step involves conversion of silver ions to metallic silver nanoparticles, through reduction of silver nitrate with dilute solution of PAN. The second step involves electrospinning of viscous PAN solution containing silver nanoparticles, thus obtaining PAN nanofibers containing silver nanoparticles. The third step was converting PAN/Ag composites into carbon nanofibers containing silver nanoparticles. Scanning electron microscopy (SEM) revealed that the diameter of the nanofibers ranged between 200 and 800 nm. Transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) showed silver nanoparticles dispersed on the surface of the carbon nanofibers. The obtained fiber was fully characterized by measuring and comparing the FTIR spectra and thermogravimetric analysis (TGA) diagrams of PAN nanofiber with and without imbedded silver nanoparticles, in order to show the effect of silver nanoparticles on the electrospun fiber properties. The obtained carbon/Ag composites were tested as gram-class-independent antibacterial agent. The electrosorption of different salt solutions with the fabricated carbon/Ag composite film electrodes was studied.     

Production and purification of ovine anti-tetanus antibody

We used the ovine as bioreactor for the production and optimization of anti-tetanus toxin antibody. Four female sheep were immunized with human tetanus vaccine (TT-alum) every two weeks for 16 weeks, after which serum was collected and its titer was estimated by ELISA. The highest titer obtained was 39,000 IU ml-1. To optimize a purification protocol for ovine anti-tetanus toxin, we used four procedures; weak anion (DEAE-Sephadex), weak cation (CM-Sephadex), ammonium sulfate precipitation alone or in combination with caprylic acid. Fifty percent saturation with ammonium sulfate combined with caprylic acid gave us the highest yield of protein with specific activity and the purest Fab product.     

Combined Effect of Soil Water Availability and Growth Substances on Some Aspects of Chemical Composition of Cowpea Plants

Cowpea plant ( Vigna sinensis Savi) were grown in pots for two successive years. These plants were daily maintained at water holding capacities (15, 25, 45 and 65 %). The foliage of plants grown at every level of soil moisture was sprayed till dripping with either IAA solutions 0, 10, 50 and 100 mg/1 or kinetin solutions 0, 10, 20 and 40 mg/1 three times after 3, 6 and 9 weeks from sowing. Samples were taken at two physiological stages before flowering and during flowering for determination of photosynthetic pigments and carbohydrate fractions.
Water stress decreased all photosynthetic pigments (chlorophyll "a", chlorophyll "b" and carotenoids). Meanwhile, it increased the ratios of "a/b" and (a + b)/carotenoids. IAA and kinetin at all concentrations increased photosynthetic pigments. In addition, the same treatments led to decrease in the ratios of "a/b" and a + b/carotenoids.
Total carbohydrate content was decreased by decreasing soil moisture content. Meanwhile, reducing sugars as well as sucrose contents were increased. IAA and kinetin increased total carbohydrate, reducing sugars and sucrose of cowpea shoots comparing with respective controls.     

Survival and fertility rate of cooled dromedary camel spermatozoa supplemented with catalase enzyme

The present study was planned to study the effects of addition of different concentrations of catalase enzyme (0, 250, 500 and 1,000 IU/ml) to cooled dromedary camel semen extended with tris-yolk-fructose extender on semen quality during storage at 5 C for up to 5 days. Conception rates of she-camels artificially inseminated with whole fresh or extended cooled dromedary camel semen with or without 500 IU/ml catalase enzyme were also estimated. The results showed that addition of catalase enzyme at concentrations of 250 or 500 IU/ml to extended cooled dromedary camel semen significantly increased (P<0.01) the percentage of sperm motility and significantly decreased (P<0.01) the percentages of dead spermatozoa, sperm abnormalities and acrosomal damage. The highest (P<0.01) percentage of sperm motility was recorded with extended cooled dromedary camel semen supplemented with catalase enzyme at a concentration of 500 IU/ml, and the lowest (P<0.01) value was recorded with catalase enzyme at a concentration of 1000 IU/ml. On the other hand, the lowest (P<0.01) percentages of dead spermatozoa, sperm abnormalities and acrosomal damage of spermatozoa were recorded with extended cooled dromedary camel semen supplemented with 500 IU/ml, and the highest (P<0.01) values were recorded with catalase enzyme at a concentration of 1,000 IU/ml. Advancement of the storage time at 5 C significantly decreased (P<0.01) the percentage of sperm motility and significantly increased (P<0.01) the percentages of dead spermatozoa, sperm abnormalities and acrosomal damage of spermatozoa. Moreover, the conception rates of she-camels artificially inseminated with whole fresh, extended cooled dromedary camel semen free-catalase enzyme and extended cooled dromedary camel semen supplemented with catalase enzyme at a concentration of 500 IU/ml were 46.15, 22.22 and 37.50%, respectively. In conclusion, the results show that addition of catalase enzyme at a concentration of 500 IU/ml to semen extender can be used as an agent for prolongation of dromedary camel sperm cell survival during storage at 5 C.     

Effect of dietary α‐tocopherol on the bioavailability of lutein in laying hen

Lutein and its isomer zeaxanthin have gained considerable interest as possible nutritional ingredient in the prevention of age‐related macular degeneration (AMD) in humans. Egg yolk is a rich source of these carotenoids. As an oxidative sensitive component, antioxidants such as α‐tocopherol (T) might contribute to an improved accumulation in egg yolk. To test this, chickens were fed lutein esters (LE) with and without α‐tocopherol as an antioxidant. After depletion on a wheat–soya bean‐based lutein‐poor diet for 21 days, laying hens (n = 42) were equally divided into three groups and fed the following diets for 21 days: control (basal diet), a LE group (40 mg LE/kg feed) and LE + T group (40 mg LE plus 100 mg T/kg feed). Eggs and blood were collected periodically. Carotenoids and α‐tocopherol in yolk and blood plasma were determined by HPLC. Egg yolk was also analysed for total carotenoids using a one‐step spectrophotometric method (iCheck^(?)). Lutein, zeaxanthin, α‐tocopherol and total carotenoids in egg yolk were highest after 14 days of feeding and decreased slightly afterwards. At the end of the trial, eggs of LE + T group contained higher amount of lutein (13.72), zeaxanthin (0.65), α‐tocopherol (297.40) and total carotenoids (21.6) compared to the LE group (10.96, 0.55, 205.20 and 18.0 mg/kg, respectively, p < 0.05). Blood plasma values of LE + T group contain higher lutein (1.3), zeaxanthin (0.06) and tocopherol (20.1) compared to LE group (1.02, 0.04 and 14.90 mg/l, respectively, p < 0.05). In conclusion, dietary α‐tocopherol enhances bioavailability of lutein reflecting higher content in egg yolk and blood plasma. Improved bioavailability might be due to increased absorption of lutein in the presence of tocopherol and/or a greater stability of lutein/zeaxanthin due to the presence of α‐tocopherol as an antioxidant.