Screening and HPLC methods for carotenoids in sweetpotato, cassava and maize for plant breeding trials

Analytical methods for sweetpotato, cassava and maize were developed. In orange and salmon-fleshed sweetpotatoes, (all-E)-β-carotene predominated and results of spectrophotometric screening and HPLC quantification did not differ significantly. In yellow-fleshed sweetpotato and cassava, however, spectrophotometric screening overestimated the HPLC values because of the presence of several minor carotenoids. Aside from (all-E)-β-carotene, Z-isomers were present in cassava in appreciable amounts. For both crops, extraction with acetone or tetrahydrofuran:methanol (1:1), using a mortar and pestle or a Polytron homogenizer, gave equivalent results. Rehydration of dry maize at room temperature for 30 min or at 85 °C for 5, 10 or 15 min gave equivalent results. Concentrations obtained with the C18 and C30 columns did not differ significantly for zeaxanthin, lutein, β-cryptoxanthin and β-carotene in the all-E-configuration, but their Z-isomers were difficult to locate in the chromatogram obtained with the C30 column. Extraction with tetrahydrofuran:methanol (1:1) gave significantly lower results for zeaxanthin and lutein.     

Hydrophilic and hydrophobic copolymers of a polyaspartylhydrazide bearing positive charges as vector for gene therapy

BACKGROUND: The design of polymeric vectors for gene delivery provided with specific properties is one of the most critical aspects for a successful gene therapy. These polymers should be biocompatible as well as able to carry efficiently DNA to target tissues and to transfect it into cells. RESULTS: The formation of complexes of poly[(α,β‐asparthylhydrazide)–poly(ethylene glycol)] and poly[(α,β‐asparthylhydrazide)–hexadecylamine] copolymers functionalised with glycidyltrimethylammonium chloride (PAHy–PEG‐GTA and PAHy–C₁₆‐GTA, respectively) with DNA was studied. The effects of the introduction of hydrophilic (PEG) or hydrophobic (C₁₆) moieties on the chains of PAHy–GTA copolymers, such as the stabilising effect on the DNA structure, were evaluated. In particular, we observed a high DNA protection by PAHy–PEG‐GTA copolymers. Degradation studies led us to suppose a particular aqueous conformation of the polyionic complex of PAHy–PEG₂₀₀₀‐GTA in which DNA should be internalised into an inner core surrounded by a PEG hydrophilic shell; while no significant protection was detected with PAHy–C₁₆‐GTA in which DNA should be disposed on the surface of the complex, freely exposed to DNase II action. CONCLUSION: The insertion of PEG or C₁₆ chains into the polymeric structure of PAHy–GTA copolymers changes significantly the DNA complexing and protecting ability of the PAHy–GTA copolymers, showing that hydrophilic and hydrophobic side chains can play a crucial role in supramolecular arrangements of interpolyelectrolyte complexes between DNA and PAHy copolymers. Copyright © 2008 Society of Chemical Industry     

Electroactive biofilms: new means for electrochemistry

This work demonstrates that electrochemical reactions can be catalysed by the natural biofilms that form on electrode surfaces dipping into drinking water or compost. In drinking water, oxygen reduction was monitored with stainless steel ultra-microelectrodes under constant potential electrolysis at −0.30 V/SCE for 13 days. 16 independent experiments were conducted in drinking water, either pure or with the addition of acetate or dextrose. In most cases, the current increased and reached 1.5–9.5 times the initial current. The current increase was attributed to biofilm forming on the electrode in a similar way to that has been observed in seawater. Epifluorescence microscopy showed that the bacteria size and the biofilm morphology depended on the nutrients added, but no quantitative correlation between biofilm morphology and current was established. In compost, the oxidation process was investigated using a titanium based electrode under constant polarisation in the range 0.10–0.70 V/SCE. It was demonstrated that the indigenous micro-organisms were responsible for the current increase observed after a few days, up to 60 mA m⁻². Adding 10 mm acetate to the compost amplified the current density to 145 mA m⁻² at 0.50 V/SCE. The study suggests that many natural environments, other than marine sediments, waste waters and seawaters that have been predominantly investigated until now, may be able to produce electrochemically active biofilms.     

Aerobic biodegradation and inhibition kinetics of poly‐aromatic hydrocarbons (PAHs) in a petrochemical industry wastewater in the presence of biosurfactants

BACKROUND: In Izmir, Turkey, wastewaters from the petrochemical industry are treated using conventional activated sludge systems. A significant proportion of poly‐aromatic hydrocarbons (PAHs) with high‐molecular weights remains in this treatment system and inhibits the biological activity. Biosurfactants increase PAHs degradation by enhancing the solubility of the petroleum components. The aerobic inhibition kinetics of PAHs has not previously been investigated in the presence of biosurfactants for a real petrochemical industry wastewater. RESULTS: Among the kinetic models used (Monod‐type, zero, first‐order and second‐order) it was found that the Monod kinetic was effective for describing the biodegradation of PAHs in petrochemcal industry wastewater in the presence of three biosurfactants, namely Rhamnolipid (RD), Surfactine (SR) and Emulsan (EM) in an aerobic activated sludge reactor (AASR). The maximum PAH removal rate (R_max) and specific growth rate of PAH degrading bacteria (µ_max) increased, while the half saturation concentration of PAH (K_s) decreased at 15 mg L^?1 RD concentration compared with the control without biosurfactant at a sludge retention time (SRT) of 25 days. CONCLUSION: PAH oxidation is typified by competitive inhibition at RD concentrations > 15 mg L^?1 resulting in increases in K_s values with PAH accumulation. Low inhibition constant (K_ID) values reflect difficulties in the metabolizability of PAHs. Metabolite production decreased at RD = 25 mg L^?1 in the PAHs indeno (1,2,3‐cd) pyrene (IcdP), flourene (FLN), phenanthrene (PHE) and benzo(a)pyrene (BaP). Copyright © 2011 Society of Chemical Industry     

Poly-phenothiazine derivative-modified glassy carbon electrode for NADH electrocatalytic oxidation

Electropolymerization of a new phenothiazine derivative (bis-phenothiazin-3-yl methane; BPhM) on glassy carbon (GC) electrode generates a conducting film of poly-BPhM, in stable contact with the electrode surface. The heterogeneous electron-transfer process corresponding to the modified electrode is characterized by a high rate constant (50.4 s⁻¹, pH 7). The GC/poly-BPhM electrode shows excellent electrocatalytic activity toward NADH oxidation. The rate constant for catalytic NADH oxidation, estimated from rotating disk electrode (RDE) measurements and extrapolated to zero concentration of NADH, was found to be 9.4 × 10⁴ M⁻¹ s⁻¹ (pH 7). The amperometric detection of NADH, at +200 mV vs. SCE, is described by the following electroanalytical parameters: a sensitivity of 1.82 mA M⁻¹, a detection limit of 2 μM and a linear domain up to 0.1 mM NADH.     

Biotransformation of Carbon Tetrachloride and Anaerobic Granulation in a Upflow Anaerobic Sludge Blanket Reactor

Carbon tetrachloride (CT) in a synthetic wastewater was effectively degraded in a 2?l upflow anaerobic sludge blanket reactor during the granulation process by increasing the chemical oxygen demand (COD) and CT loadings. The effect of operational parameters such as influent CT concentrations, COD, CT loading, food to mass (F/M) ratio, and specific methanogenic activity (SMA) were also detected during granulation. Over 97% of CT was removed at 37°C, at a COD loading rate of 10?g/L?day. Chemical oxygen demand and CT removal efficiencies of 92 and 88% were achieved when the reactor was operating at CT and COD loading rates of 17.5?mg/L?day and 12.5?g/L?day, respectively. This corresponds to an hydraulic retention time of 0.28?day and an F/M ratio of 0.57?g?COD/g?volatile?suspended?solids?(VSS)?day. In 4?weeks, the seed sludge developed the CT degrading capability that was not very sensitive to shocks. The granular sludge cultivated had a maximum diameter of 2.5?mm and SMA of 1.64?g?COD/g?VSS?day. Glucose biodegradation by CT acclimated anaerobic granules was expressed with competitive inhibition. However the competitive inhibition was not significant since the competitive inhibition coefficient (Ki) was as high as 18.72?mg/L. Kinetic coefficients of k (maximum specific substrate utilization rate), Ks (half velocity coefficient), Y (growth yield coefficient), and b (decay coefficient) were determined as 0.6/day, 1.1?mg/L, 0.23?g?VSS/g glucose-COD, and 0.01/day, respectively, based on growth substrate glucose–COD during CT biotransformation. The CT was treated via biodegradation and this contributed to 89% of the total removal. The removal contributions from biomass adsorption, abiotic transformation, and volatilization were negligible. Adsorption and volatilization accounted for only 0.8 and 0.5% of the total removal, respectively.     

Scientific integrity resource guide: Efforts by federal agencies,foundations, nonprofit organizations,professional societies,and academia in the United States

Scientific integrity is at the forefront of the scientific research enterprise. This paper provides an overview of key existing efforts on scientific integrity by federal agencies, foundations, nonprofit organizations, professional societies, and academia from 1989 to April 2016. It serves as a resource for the scientific community on scientific integrity work and helps to identify areas in which more action is needed. Overall, there is tremendous activity in this area and there are clear linkages among the efforts of the five sectors. All the same, scientific integrity needs to remain visible in the scientific community and evolve along with new research paradigms. High priority in instilling these values falls upon all stakeholders.