A method for simply and cheaply preparing inorganic phosphor nanoparticles of Eu2O3 as labels in biology has been demonstrated with a simple microwave-assisted surface chemistry. The capping process adds a silane layer to the surface of the particles and provides amine groups that can be used for biological conjugation. The surface layer also protects the particles during conjugation chemistry. The particles retain their desirable optical properties that are typical of europium, that is, a spectrally narrow, red emission and a long fluorescence lifetime. The application of the nanoparticle labels in an immunoassay yields very good sensitivity in an immunoassay for atrazine (sub-parts-per-billion detection limit) without optimization of the detection system. The microwave functionalization technique will permit a broad range of inorganic nanophase phosphors to be used in high-throughput assays for environmental monitoring.

Although the relevance of biological N nutrition of soybean [Glycine max (L.) Merr.] is recognized worldwide, inoculation with Bradyrhizobium japonicum shows variable results and the benefi t needs to be validated under current crop production practices. We conducted statistical analysis of soybean fi eld trial data to provide insight into factors aff ecting the effi cacy of soybean inoculation under contrasting crop production conditions. Most experimental sites, 187 trials in the United States and 152 trials in Argentina, were in soils with soybean history and naturalized B. japonicum strains. Yield increases were greater in Argentina (190 kg ha -1 equivalent to 6.39%) than in the United States (60 kg ha -1 equivalent to 1.67%). Tillage methods did not aff ect inoculant performance. In the United States, inoculation was more eff ective in soils with higher pH (>6.8) while in Argentina the greatest inoculation eff ect on crop production occurred in soils with a lower pH (<5.5). In the United States, where most of the trials were in rotation with corn (Zea mays L), the greatest positive eff ect of inoculation was observed in late planted soybean crops and independent of soil organic matter (SOM). In Argentina, the inoculant had its greatest eff ect in soils with no soybean history, a relatively high SOM, higher levels of soil extractable P and S, and in areas with greater precipitation during early reproductive growing stages. In both regions, the yield increases due to B. japonicum inoculation support the regular use of this practice to help provide adequate conditions for soybean production.M. Leggett, Novozymes BioAg, Research and Development, 3935 Th atcher Ave.,

SUMMARYFindings from multi-year, multi-site field trial experiments measuring maize yield response to inoculation with the phosphorus-solubilizing fungus, Penicillium bilaiae Chalabuda are presented. The main objective was to evaluate representative data on crop response to the inoculant across a broad set of different soil, agronomic management and climate conditions. A statistical analysis of crop yield response and its variability was conducted to guide further implementation of a stratified trial and sampling plan. Field trials, analysed in the present study, were conducted across the major maize producing agricultural cropland of the United States (2005–11) comprising 92 small (with sampling replication) and 369 large (without replication) trials. The multi-plot design enabled both a determination of how sampling area affects the estimation of maize yield and yield variance and an estimation of the ability of inoculation with P. bilaiae to increase maize yield. Inoculation increased maize yield in 66 of the 92 small and 295 of the 369 large field trials (within the small plots, yield increased significantly at the 95% confidence level, by 0·17 ± 0·044 t/ha or 1·8%, while in the larger plots, yield increases were higher and less variable (i.e., 0·33 ± 0·026 t/ha or 3·5%). There was considerable inter-annual variability in maize yield response attributed to inoculation compared to the un-inoculated control, with yield increases varying from 0·7 ± 0·75 up to 3·7 ± 0·73%. No significant correlation between yield response and soil acidity (i.e., pH) was detected, and it appears that pH reduction (through organic acid or proton efflux) was unlikely to be the primary pathway for better phosphorus availability measured as increased yield. Seed treatment and granular or dribble band formulations of the inoculant were found to be equally effective. Inoculation was most effective at increasing maize yield in fields that had low or very low soil phosphorus status for both small and large plots. At higher levels of soil phosphorus, yield in the large plots increased more with inoculation than in the small plots, which could be explained by phosphorus fertilization histories for the different field locations, as well as transient (e.g., rainfall) and topographic effects.

Discovery of novel natural herbicides has become crucial to overcome increasing weed resistance and environmental issues. In this article, we describe the finding that a methanol extract of dry long pepper (Piper longum L.) fruits is phytotoxic to lettuce (Lactuca sativa L.) seedlings. The bioassay-guided fractionation and purification of the crude extract led to isolation of sarmentine (1), a known compound, as the active principle. Phytotoxicity of 1 was examined with a variety of seedlings of field crops and weeds. Results indicated that 1 was a contact herbicide and possessed broad-spectrum herbicidal activity. Moreover, a series of sarmentine analogues were then synthesized to study the structure−activity relationship (SAR). SAR studies suggested that phytotoxicity of sarmentine and its analogues was specific due to chemical structures, i.e., the analogues of the acid moiety of 1 were active, but the amine and its analogues were inactive; the ester analogues and amide analogues with a primary amine of 1 were also inactive. In addition, quantification of 1 from different resources of the dry P. longum fruits using liquid chromatography−mass spectrometry showed a wide variation, ranging from almost zero to 0.57%. This study suggests that 1 has potential as an active lead molecule for synthesized herbicides as well as for bioherbicides derived from natural resources.