Huitlacoche (ustilago maydis) as a food source — biology,composition, and production

Huitlacoche is the ethnic name applied to the young fruiting bodies (galls) of the fungus Ustilago maydis, which causes common smut of maize (Zea mays L). Biologists and agronomists have historically used U. maydis as a model to study a wide array of genetic, physiological, ecological, and phytopathological phenomena. In Mexico and other Latin American countries, huitlacoche has been used traditionally as human food, being highly regarded as an interesting dish or condiment. The food potential of huitlacoche is described here in terms of its chemical composition, which includes carbohydrates, proteins, fats, vitamins, and minerals. In addition, essential amino acids (especially lysine) and fatty acids (linoleate) are present in huitlacoche in considerable levels, adding to its nutritional attributes. The feasibility of growing U. maydis in submerged agitated culture has yielded a variety of fermentation products, including essential amino acids, proteins, vitamins, and flavorings, among others. Recent interest in developing huitlacoche as a cash crop has come from increasing acceptance by the North American public, who prize it as a new delicacy. However, research efforts are still needed to determine the biological factors involved in the establishment of U. maydis as a pathogen on the maize plant. This review deals with the role of huitlacoche as a food source, implicating the biological components that will determine the development of technologies for large scale production.     

Galena weathering under simulated calcareous soil conditions

Exploitation of polymetallic deposits from calcareous mining sites exposes galena and others sulfides to weathering factors. Galena weathering leads to the formation of lead phases (e.g., PbSO₄, PbCO₃) with a higher bioaccessibility than galena, thus increasing the mobility and toxicity of lead. Despite the environmental impacts of these lead phases, the mechanisms of galena oxidation and the transformation of lead secondary phases, under neutral-alkaline carbonated conditions, have rarely been studied. In this work, an experimental approach, combining electrochemical and spectroscopic techniques, was developed to examine the interfacial processes involved in the galena weathering under simulated calcareous conditions. The results showed an initial oxidation stage with the formation of an anglesite-like phase leading to the partial mineral passivation. Under neutral-alkaline carbonated conditions, the stability of this phase was limited as it transformed into a cerussite-like one. Based on the surface characterization and the formation of secondary species, the weathering mechanisms of galena in calcareous soil and its environmental implications were suggested.     

Effect of photoperiod on flavonoid pathway activity in sweet potato (Ipomoea batatas (L.) Lam.) leaves

Compared with those of major commercial leafy vegetables, leaves of sweet potato have higher contents of flavonoids and phenolic acids, which provide significant health benefits and may be used as natural colourants. We have analysed the expression of key flavonoid biosynthesis genes using RT-PCR and the accumulation of polyphenolic compounds using high-performance liquid chromatography coupled to a photodiode-array detector, during the development of leaves of sweet potato plants growing under either long day or short day photoperiods. A massive induction of flavonoid pathway gene expression, correlating with a dramatic increase in the content of an anthocyanin, catechins, flavonols, hydroxycinnamic acids and hydroxybenzoic acids, was observed during sweet potato leaf exposure to a long day photoperiod. These results provide further support for the protective role of flavonoids and phenolic acids against enhanced light exposure in plants.     

Effect of ozone on nicotine desorption from model surfaces: evidence for heterogeneous chemistry

Assessment of secondhand tobacco smoke exposure using nicotine as a tracer or biomarker is affected by sorption of the alkaloid to indoor surfaces and by its long-term re-emission into the gas phase. However, surface chemical interactions of nicotine have not been sufficiently characterized. Here, the reaction of ozone with nicotine sorbed to Teflon and cotton surfaces was investigated in an environmental chamber by monitoring nicotine desorption over a week following equilibration in dry or humid air (approximately 0% or 65-70% RH, respectively). The Teflon and cotton surfaces had N2-BET surface areas of 0.19 and 1.17 m2 g(-1), and water mass uptakes (at 70% RH) of 0 and 7.1% respectively. Compared with dry air baseline levels in the absence of O3, gas-phase nicotine concentrations decreased by 2 orders of magnitude for Teflon after 50 h at 20-45 ppb O3, and by a factor of 10 for cotton after 100 h with 13-15 ppb O3. The ratios of pseudo first-order rate constants for surface reaction (r) to long-term desorption (k) were r/k = 3.5 and 2.0 for Teflon and cotton surfaces, respectively. These results show that surface oxidation was competitive with desorption. Hence, oxidative losses could significantly reduce long-term re-emissions of nicotine from indoor surfaces. Formaldehyde, N-methylformamide, nicotinaldehyde, and cotinine were identified as oxidation products, indicating that the pyrrolidinic N was the site of electrophilic attack by O3. The presence of water vapor had no effect on the nicotine-O3 reaction on Teflon surfaces. By contrast, nicotine desorption from cotton in humid air was unaffected by the presence of ozone. These observations are consistent with complete inhibition of ozone-nicotine surface reactions in an aqueous surface film present in cotton but not in Teflon surfaces.     

Nootkatone Is a Repellent for Formosan Subterranean Termite (Coptotermes formosanus)

We examined the behavior of Formosan subterranean termites toward one of the components of vetiver grass oil, the roots of which manufacture insect repellents. We found nootkatone, a sesquiterpene ketone, isolated from vetiver oil is a strong repellent and toxicant to Formosan subterranean termites. The lowest effective concentration tested was 10 g/g substrate. This is the first report of nootkatone being a repellent to insects.     

Enhancement of mechanical properties and chemical durability of Soda-lime silicate glasses treated by DC gas discharges

We report for the first time a study on non-contact thermal poling of soda lime silicate glasses using DC gas discharge. In this work, the formation of a glow discharge is evidenced during the thermal poling treatment (longer than 30 minutes). The hardness and the chemical durability of glasses poled under different conditions (contact or non-contact) and atmospheres (nitrogen or air) are measured and compared to that of un-poled reference glass. The results reveal enhanced mechanical and chemical properties for samples poled under nitrogen as compare to air poled or soda lime silicate glass samples. A structural and chemical analysis of surface of the glass using IR-reflectance measurement and ToF-SIMS is also presented. The formation of a “silica-like” layer on the surface of nitrogen poled glasses is observed, which is likely associated with the enhancement of surface properties. On the other hand, the introduction of protons beneath the surface of glasses poled under air leads to the formation of a hydrated alkaline earth silica layer. Based on the observations a mechanism behind the sustainability of the plasma under DC conditions is proposed.     

Principles and Design Strategies for Ultra-efficient Production Systems in the Process Industry

A sustainable design of production systems, both within and beyond company boundaries, is essential for the future viability of the process industry. In this context, the concept of ultra-efficiency has recently been developed, aiming at achieving holistic improvements in the fields of action energy and material efficiency, emission reduction, organization, human and staff, with the goal of establishing a positive impact factory. In this paper, the concept developed mainly for the discrete manufacturing industry is transferred to the process industry. It is put into the scientific sub context and elementary approaches, methods and strategies for factory planning and design of production processes in the process industry are summarized.     

Use of a bis(aminoalkyl)-calix[4]arene derivative as cross-linking agent to enhance functional and mechanical properties of a maleated polypropylene

An isotactic polypropylene grafted by 1 wt% of maleic anhydride (iPP-g-MAH) was chemically modified to provide it with new functional abilities and improved mechanical properties. The specific additive considered in this work is a derivative of bis(aminoalkyl)-calix[4]arene. Not only this molecule serves as a cross-linking agent, but it offers grafting sites for metallic ions that confer electrolytic conductivity to the initially insulating polyolefin. Materials were synthesized by reactive extrusion, and subsequently manufactured as plates by injection molding. The three-dimensional macromolecular architecture was optimized by adjusting the NH₂:MAH molar ratio in a range from 0.5:1 to 1:1. Fourier transform infrared spectroscopy revealed the amine/ anhydride chemical reactions, while gel content measurements were used to determine the degree of cross-linking. The crystalline microstructure of the different materials was characterized by two complementary methods: (a) overall crystallinity by differential scanning calorimetry; (b) lamellar thickness by thermal fractionation using the self-successive auto-nucleation procedure. Only a small decrease of the crystalline lamellae is observed. The mechanical properties were determined by a video-controlled tensile testing method and by Brillouin spectroscopy. A transition from brittle to ductile behavior was observed for increasing cross-links density. Scanning electron microscopy on fracture surfaces showed that ductile fracture was favored by the development of fibrils.