Penicillium expansum Volatiles Reduce Pine Weevil Attraction to Host Plants

The pine weevil Hylobius abietis (L.) is a severe pest of conifer seedlings in reforested areas of Europe and Asia. To identify minimally toxic and ecologically sustainable compounds for protecting newly planted seedlings, we evaluated the volatile metabolites produced by microbes isolated from H. abietis feces and frass. Female weevils deposit feces and chew bark at oviposition sites, presumably thus protecting eggs from feeding conspecifics. We hypothesize that microbes present in feces/frass are responsible for producing compounds that deter weevils. Here, we describe the isolation of a fungus from feces and frass of H. abietis and the biological activity of its volatile metabolites. The fungus was identified by morphological and molecular methods as Penicillium expansum Link ex. Thom. It was cultured on sterilized H. abietis frass medium in glass flasks, and volatiles were collected by SPME and analyzed by GC-MS. The major volatiles of the fungus were styrene and 3-methylanisole. The nutrient conditions for maximum production of styrene and 3-methylanisole were examined. Large quantities of styrene were produced when the fungus was cultured on grated pine bark with yeast extract. In a multi-choice arena test, styrene significantly reduced male and female pine weevils’ attraction to cut pieces of Scots pine twigs, whereas 3-methylanisole only reduced male weevil attraction to pine twigs. These studies suggest that metabolites produced by microbes may be useful as compounds for controlling insects, and could serve as sustainable alternatives to synthetic insecticides.     

A simple purification and activity assay of the coagulant protein from Moringa oleifera seed

Use of extracts from Moringa oleifera (MO) is of great interest for low-cost water treatment. This paper discusses water and salt extraction of a coagulant protein from the seed, purification using ion exchange, its chemical characteristics, coagulation and antimicrobial properties. The coagulant from both extracts is a cationic protein with pI greater than 9.6 and molecular mass less than 6.5 kDa. Mass spectrometric analysis of the purified water extract indicated that it contained at least four homologous proteins, based on MS/MS peptide sequence data. The protein is thermoresistant and remained active after 5h heat treatment at 95 degrees C. The coagulant protein showed both flocculating and antibacterial effects of 1.1--4 log reduction. With samples of high turbidity, the MO extract showed similar coagulation activity as alum. Cecropin A and MO extract were found to have similar flocculation effects for clay and microorganisms. Simple methods for both the purification and assay of MO coagulating proteins are presented, which are necessary for large-scale water treatment applications.     

The effectiveness of extension strategies for increasing the adoption of biofortified crops: the case of quality protein maize in East Africa

Biofortified crops can be promoted with extension strategies based on their agronomic qualities, nutritional qualities, or both, but the effectiveness of these different strategies has so far not been studied. Since 2003, quality protein maize (QPM) has been disseminated using both approaches in East Africa. This study therefore analyzes the effectiveness of promoting biofortified crops based on their agronomic and their nutritional qualities, using the adoption of QPM cultivars in East Africa as an example. A random sample survey was conducted in Ethiopia, Kenya, Tanzania, and Uganda, with 423 households from QPM extension areas and 539 households from similar areas outside the extension zone. Propensity score matching and regression analysis were used to assess determinants of QPM adoption, including farmers’ awareness of QPM, understanding of its nutritional benefits, and evaluation of agronomic performance to evaluate the agronomic and nutritional extension strategies. Results showed high familiarity with QPM, but low understanding of nutritional benefits. Farmers evaluated QPM varieties as equal or superior to conventional maize for post-harvest traits, but not always for agronomic traits (in particular yield in Ethiopia and Tanzania). Adoption in extension areas varied from 73 % in Uganda and 25 % in Tanzania to none in Kenya. Key factors that increased adoption were farmers’ participation in extension, having heard of QPM, higher overall evaluation ratings of QPM vs. conventional maize varieties, and understanding of QPM’s nutritional benefits. Agronomic performance was found to be more important than an understanding of nutritional benefits. For biofortified crops to be adopted and have a nutritional impact on target populations, they should, first and foremost, be agronomically equal or superior to conventional varieties. If farmers are convinced of the agronomic performance of biofortified crops, additional gains in adoption can be achieved by focusing extension efforts on imparting to farmers knowledge of the benefits of biofortified crops for human nutrition.     

Application of magnetic iron oxide nanoparticles prepared from microemulsions for protein purification

BACKGROUND: Magnetic nanoparticles are of immense interest for their applications in biotechnology. This paper reports the synthesis of magnetic iron oxide nanoparticles from two different water‐in‐oil microemulsion systems (ME‐MIONs), their characterization and also their use in purification of coagulant protein. RESULTS: ME‐MIONs have demonstrated to be an efficient binder in the purification of Moringa oleifera protein when compared with the superparamagnetic iron oxide nanoparticles prepared from coprecipitation in aqueous media. The size and morphology of the ME‐MIONs were studied by transmission electron microscopy (TEM) while the structural characteristics were studied by X‐ray diffraction (XRD). The microemulsion magnetic iron oxide nanoparticles (ME 1‐MION and ME 2‐MION) obtained have a size range 7–10 nm. The protein and ME‐MIONs interaction was investigated by Fourier transform infrared spectroscopy (FT‐IR); the presence of three peaks at 2970, 2910 and 2870 cm^?1 respectively, confirms the binding of the protein. The purification and molecular weight of the coagulant protein was 6.5 kDa as analyzed by SDS‐PAGE. CONCLUSION: The ME‐MIONs have the advantage of being easily tailored in size, are highly efficient as well as magnetic, cost effective and versatile; they are, thus, very suitable for use in a novel purification technique for protein or biomolecules that possess similar characteristics to the Moringa oleifera coagulant protein. Copyright © 2011 Society of Chemical Industry     

Characterization of superparamagnetic iron oxide nanoparticles and its application in protein purification

The application of surface modified magnetic adsorbent particles in combination with magnetic separation techniques has received considerable awareness in recent years. There is a particular need in protein purification and analysis for specific, functional and generic methods of protein binding on solid supports. Nanoscale superparamagnetic iron oxide particles have been used to purify a natural coagulant protein extracted from Moringa oleifera seeds. Spectrophotometric analysis of the coagulant protein was performed using synthetic clay solution as substrate. Protein binding with carboxyl and silica surface modified superparamagnetic iron oxide nanoparticles (SPION) were compared with the known carboxyl methyl cellulose (CMC) beads of approximately 1 microm. SPION modified with carboxyl surface showed higher binding capacity towards the coagulant protein compared to the CMC beads. The high surface area to volume ratio of the carboxyl-coated SPION resulted in high binding capacity and rapid adsorption kinetics of the crude protein extract. The purification and molecular weight of coagulant protein is analyzed by SDS-PAGE. This approach utilizes the most efficient, feasible and economical method of coagulant protein purification and it can also be applicable to other proteins that possess similar properties.     

Dyed Microspheres for Quantification of UV Dose Distributions: Photochemical Reactor Characterization by Lagrangian Actinometry

Lagrangian actinometry represents a new method of photochemical reactor characterization. The method is based on an application of dyed microspheres, which were developed by attachment of (E)-5-[2-(methoxycarbonyl)ethenyl]cytidine (hereafter referred to as S) to polystyrene microspheres. S is a nonfluorescent molecule that when subjected to ultraviolet (UV) irradiation yields a single product, 3-β-D-ribofuranosyl-2,7-dioxopyrido[2,3-d]pyrimidine (hereafter referred to as P), which displays a strong fluorescence signal. Dyed microspheres were subjected to UV irradiation under a collimated beam and using a single-lamp, monochromatic (low pressure Hg), continuous-flow reactor. In parallel with these experiments, a biodosimetry experiment was conducted using Bacillus subtilis spores as the challenge organism. Particle-specific fluorescence intensity measurements were conducted on samples from the collimated-beam experiments and the flow-through reactor experiments by flow cytometry. Estimates of the dose distribution delivered by the flow-through reactor for each operating condition were developed by deconvolution of data resulting from flow cytometry analysis of these samples. In conjunction with these experiments, a numerical model was developed to simulate the behavior of the reactor system. A commercially available computational fluid dynamics package was used to simulate the flow field, while line-source integration was used to simulate the irradiance field. A particle-tracking algorithm was employed to interrogate the flow and irradiance field simulations for purposes of developing particle-specific (Lagrangian) estimates of dose delivery. Dose distribution estimates from the microspheres assays and the numerical simulations were combined with the measured dose–response behavior of B. subtilis spores to yield estimates of spore inactivation in the flow-through experiments. For the range of operating conditions used in these experiments, predictions of spore inactivation based on dose distribution estimates from both methods were in good agreement with each other, and with the measured spore inactivation behavior. Lagrangian actinometry is capable of yielding accurate, detailed measurements of dose delivery by continuous-flow UV systems. This method represents a substantial improvement over existing experiment-based methods of UV reactor characterization (e.g., biodosimetry) in that it yields a measurement of the dose distribution for a given operating condition. This method also represents an improvement over existing methods for validation of numerical simulations. Specifically, because this method yields a measurement of the dose distribution, it is possible to compare these measurements with predicted dose distributions from the numerical simulation. The combined application of biodosimetry, numerical modeling, and Lagrangian actinometry represents an extremely robust approach to reactor characterization and validation.     

Optimization of multienzyme flow reactors for determination of acetylcholine

Immobilized enzyme reactors have been used with high-performance liquid chromatography (HPLC) and electrochemical detection to detect acetylcholine and choline in brain tissue samples. Acetylcholine and choline eluting from the LC column are introduced into a reactor containing immobilized acetylcholinesterase, which hydrolyzes acetylcholine to choline. The product is converted by a second enzyme, choline oxidase, to hydrogen peroxide, which is determined amperometrically. Several novel immobilization techniques including immobilization through enzyme-specific antibodies were used to immobilize these enzymes to retain maximum activity. Improved detection limits were observed when the enzymes were immobilized through the avidin-biotin linkage. Better sensitivity and detection limit were obtained when both enzymes were immobilized together on the same support through the avidin-biotin linkage than when they were separately immobilized and used in two columns. The postcolumn system was applied to brain tissue extracts.     

Mining maize diversity and improving its nutritional aspects within agro‐food systems

Agro‐food systems are undergoing rapid innovation in the world and the system's continuum is promoted at different scales with one of the main outcomes to improve nutrition of consumers. Consumer knowledge through educational outreach is important to food and nutrition security and consumer demands guide breeding efforts. Maize is an important part of food systems. It is a staple food and together with rice and wheat, they provide 60% of the world's caloric intake. In addition to being a major contributor to global food and nutrition security, maize forms an important part of the culinary culture in many areas of Africa, the Americas, and Asia. Maize genetics are being exploited to improve human nutrition with the ultimate outcome of improving overall health. By impacting the health of maize consumers, market opportunities will be opened for maize producers with unique genotypes. Although maize is a great source of macronutrients, it is also a source of many micronutrients and phytochemicals purported to confer health benefits. The process of biofortification through traditional plant breeding has increased the protein, provitamin A carotenoid, and zinc contents of maize. The objective of this paper is to review the innovations developed and promoted to improve the nutritional profiles of maize and outcomes of the maize agro‐food system.