Life history and species composition of the damselfly assemblage along the urban tract of a river in central Italy

The species composition of the damselfly assemblage and the life history patterns of two Coenagrionidae (Ischnura elegans and Cercion lindeni) were investigated along the urban tract of a river characterized by increasing organic pollution. The assemblage was dominated by generalist species, usually recorded in lentic habitats, rather than by typical riverine species and the proportion of the latter decrease at the most polluted sites. At the end of Winter, the mean size and in star distribution were different between the sampling sites showing that the life history of both species examined were influenced by a degradation of the environmental quality. A longer reproductive period, absence of diapause, and tolerance of low oxygen concentration appear to be key factors that allow generalist species I. elegans and C. lindeni to predominate at the polluted sites. This revised version was published online in August 2006 with corrections to the Cover Date.     

Decreased lipolysis in peanuts by a pyridazinone bioregulator

Peanut,Arachis hypogaea, plants were treated in the field with the bioregulator BAS 105 00W, 4-chloro-5-dimethylamino-2-phenylpyridazin-3-one, a substituted pyridazinone, at different times of development. The seeds were harvested, dried, hand-shelled, and analyzed for lipoxygenase activity and conjugated diene hydroperoxide content. Reduced lipoxygenase activity occurred when the bioregulator was applied to the plants at flowering and pegging. The conjugated diene hydroperoxide content decreased the most in peanuts when the bioregulator was applied at pegging. The apparent K_m for lipoxygenase of treated peanuts with linoleic acid as substrate was the same as that for untreated peanuts.     

Studies on the molecular basis of H+ translocation by cytochromec oxidase

We report here studies which characterize further the interaction ofN,N-dicyclohexylcarbodiimide with cytochromec oxidase leading to inhibition of H⁺ translocation by the enzyme. Further evidence is presented to show that the inhibition results from a real interaction of DCCD with the enzyme and cannot be accounted for by uncoupling and, contrary to recent criticisms, this interaction occurs specifically with subunit III of the enzyme even at relatively high inhibitor-to-enzyme stoichiometries. Use of a spin-label analogue of DCCD has enabled us to demonstrate that the carbodiimide-binding site is highly apolar and may not lie on the pathway of electron transfer.Abbreviations DCCD N,N-dicyclohexylcarbodiimide - NCCD N-(2, 2, 6, 6-tetramethylpiperidyl-1-oxyl)-N-(cyclohexyl)carbodiimide - Hepes 2-(N-2-hydroxyethylpiperazin-N-yl) ethane sulfonate - TMPD N,N,N,N-tetramethylphenylenediamine     

An improved detection system applied to the study of serum lipoproteins after single-step density gradient ultracentrifugation

Starting from a single-spin ultracentrifugation procedure described previously (Foreman et al., J. Lipid Res. 18, 759, 1977), we have improved the system for detection of the fractions eluted from the gradient by monitoring them continuously at 280 nm. A graphic display readily permits assessment of the distribution of the lipoproteins and their quantification with the aid of a computer program. By the use of appropriate factors, one can convert absorbance readings into actual lipoprotein values which correspond well (±7% for low-density lipoproteins and ±5% for high-density lipoproteins) to those obtained by means of chemical analyses. The examples provided indicate the versatility of the method and its sensitivity (down to 0.1 ml of serum).