Eggs of cabbage root fly stimulate conspecific oviposition: Evaluation of the activity and determination of an egg-associated compound

Summary. Previous studies indicated the presence of antennally-active compounds in extracts of eggs laid by female cabbage root flies, Delia radicum, that stimulated oviposition by conspecific females. We confirmed that previously laid D. radicum eggs stimulated oviposition by other D. radicum females, in a dose-dependent manner. Methanol extracts of conspecific eggs stimulated oviposition by females D. radicum, whereas egg extracts of D. antiqua and Psila rosae had no effect. Electrophysiological recordings from the tarsal sensilla of D. radicum females indicated that neurones of the C₅ sensillum responded to the egg extracts from both D. radicum and D. antiqua, but not P. rosae. Chemical analysis revealed that the extract of eggs from D. radicum contained the thia-triaza-fluorene compound, 1,2-dihydro-3-thia-4,10,10b-triaza-cyclopenta[.a.]fluorene-1-carboxylic acid (CIF-1), an oviposition stimulant found previously only in cruciferous plants. Another potentially active component has yet to be identified.     

The ultraviolet photolysis of tetrachlorodibenzofurans

Several tetrachlorodibenzofuran isomers were photolyzed by ultraviolet irradiation and the relative amounts of the various trichlorodibenzofurans produced were determined. A simple set of guidelines for predicting the relative amounts of these photolysis products has been formulated.     

Genetic engineering for practical application

Genetic engineering has ushered in a new era in biology. Although many problems are still to be solved, there are examples that point to a possible later application for the benefit of mankind: Bacteria can be manipulated to degrade crude-oil spillages, to produce human insulin and to bind nitrogen from the air. If all the bacteria that are indigenous to agricultural soils could be made to bind nitrogen, an increase in soil fertility might well result.     

Quantitative Bestimmung des lokalen Flusses mit elektrochemisch erzeugtem Wasserstoff

The Science of Nature -     

Sekundärrohstoffe aus Abfall-Lösungen

Every year about 40 000 m³ of waste solutions from photographic fixing and developing processes are produced in Germany. A new method of reclaiming some base chemicals (silver, fixing salt, gypsum and ammonia) from these solutions has been developed for black and white photographic processes. The remaining waste water has a low COD-value and low concentration of dissolved salts. This method is considered further to develop the state-of-the-art technique and is economically feasible.