Converting simulated total dry matter to fresh marketable yield for field vegetables at a range of nitrogen supply levels

Simultaneous analysis of economic and environmental performance of horticultural crop production requires qualified assumptions on the effect of management options, and particularly of nitrogen (N) fertilisation, on the net returns of the farm. Dynamic soil-plant-environment simulation models for agro-ecosystems are frequently applied to predict crop yield, generally as dry matter per area, and the environmental impact of production. Economic analysis requires conversion of yields to fresh marketable weight, which is not easy to calculate for vegetables, since different species have different properties and special market requirements. Furthermore, the marketable part of many vegetables is dependent on N availability during growth, which may lead to complete crop failure under sub-optimal N supply in tightly calculated N fertiliser regimes or low-input systems. In this paper we present two methods for converting simulated total dry matter to marketable fresh matter yield for various vegetables and European growth conditions, taking into consideration the effect of N supply: (i) a regression based function for vegetables sold as bulk or bunching ware and (ii) a population approach for piecewise sold row crops. For both methods, to be used in the context of a dynamic simulation model, parameter values were compiled from a literature survey. Implemented in such a model, both algorithms were tested against experimental field data, yielding an Index of Agreement of 0.80 for the regression strategy and 0.90 for the population strategy. Furthermore, the population strategy was capable of reflecting rather well the effect of crop spacing on yield and the effect of N supply on product grading

Bioactive bromophycolides R-U from the Fijian red alga Callophycus serratus

Four new bromophycolides, R−U (1−4), were isolated from the Fijian red alga Callophycus serratus and were identified by 1D and 2D NMR and mass spectroscopic analyses. These compounds expand the known structural variety of diterpene-benzoate macrolides and exhibited modest cytotoxicity toward selected human cancer cell lines. Bromophycolide S (2) also showed submicromolar activity against the human malaria parasite Plasmodium falciparum

Searching for new cures for tuberculosis: design, synthesis, and biological evaluation of 2-methylbenzothiazoles

The actual development and clinical use of new therapeutics for tuberculosis (TB) have remained stagnant for years because of the complexity of the disease process, the treatment of which at present requires the administration of drug combinations over a 6 month period. There is thus an urgent need for the discovery and development of novel, more active, and less toxic anti-TB agents. In this study, we report on the chemistry and biology of a series of potent 5-(2-methylbenzothiazol-5-yloxymethyl)isoxazole-3-carboxamide derivatives, which proved to be active against replicating Mycobacterium tuberculosis (Mtb) H(37)Rv. The most potent compounds 7j and 7s were found to inhibit Mtb growth at micromolar concentrations, with MIC values of 1.4 and 1.9 microM, respectively. Impressively, all active compounds were nontoxic toward Vero cells (IC(50) < 128 microM). Moreover, the best of these compounds were also tested against protozoan parasites, and some of these compounds were found to show activity, especially against Plasmodium falciparum. These studies thus suggest that certain 2-methylbenzothiazole based compounds may serve as promising lead scaffolds for further elaboration as anti-TB drugs and as possible antimalaria drug