Preliminary observations on the population development of anystid and free-living mesostigmatic mites in a cereal field in Southern England

The effect of manipulating cereal aphid population development, by either adding aphids or spraying with an aphid-specific insecticide, on the predatory mite fauna was investigated. Populations of the anystid mite, Anystis baccarum (L.) were very small until late June when numbers built up rapidly at the time of the aphid population decline. There was however, no significant relationship between aphids and numbers of mites over the whole season. Preliminary electrophoretic analysis of two enzymes in the gut of anystid mites indicated that they may have been feeding on thrips, Limothrips cerealium Haliday. The free-living soil Mesostigmata had two population peaks, each related, the first positively and the second negatively to aphid populations.     

Wave-separation in complex systems. Application to brain-signals

A departure from single-system dynamics, that may arise in characterizing self-organized dynamics of complex systems, is dealt with by using the Karhunen-Loève expansion of the trajectory matrix to decompose an experimental signal in a sum of spectral features. For an electroencephalographic -signal, a separation of waves and extraction of additive sub-signals are achieved, each sub-signal covering a well-bounded and physiologically meaningful frequency range. From the subsignals, an attractor that vanishes on phase-randomizing the data is characterized, under conditions where none was found for the recorded signal.     

Identification of different species ofPenicillium causing deterioration of the Moroccan table grapes during storage

Penicillium glabrum, P. purpurescens, P. decumbens, P. expansum, P. chrysogenum, P. crustosum andP. aurantiogriseum are responsible for some of the alterations noticed on Moroccan table grapes cold stored. Contamination of these table grapes withPenicillium species occurs in the vineyard and inside the cooling station where other fruits which are often fungus-contaminated are also kept. All of thesePenicillium species were able to grow at 0°C apart fromP. glabrum andP. purpurescens. Consequently, refrigeration of grapes during long-term storage is not sufficient in itself in preserving their initial qualities.     

Molecular phylogenetic study of flavonoids in medicinal plants: a case study family Apiaceae

Journal of Plant Research - The current study examined the phylogenetic pattern of medicinal species of the family Apiaceae based on flavonoid groups production, as well as the overall mechanism of...     

First chemical synthesis of a scorpion alpha-toxin affecting sodium channels: the Aah I toxin of Androctonus australis hector.

Aah I is a 63-residue alpha-toxin isolated from the venom of the Buthidae scorpion Androctonus australis hector, which is considered to be the most dangerous species. We report here the first chemical synthesis of Aah I by the solid-phase method, using a Fmoc strategy. The synthetic toxin I (sAah I) was renatured in DMSO-Tris buffer, purified and subjected to thorough analysis and comparison with the natural toxin. The sAah I showed physico-chemical (CD spectrum, molecular mass, HPLC elution), biochemical (amino-acid composition, sequence), immunochemical and pharmacological properties similar to those of the natural toxin. The synthetic toxin was recognized by a conformation-dependent monoclonal anti-Aah I antibody, with an IC50 value close to that for the natural toxin. Following intracerebroventricular injection, the synthetic and the natural toxins were similarly lethal to mice. In voltage-clamp experiments, Na(v) 1.2 sodium channel inactivation was inhibited by the application of sAah I or of the natural toxin in a similar way. This work describes a simple protocol for the chemical synthesis of a scorpion alpha-toxin, making it possible to produce structural analogues in time.     

Structure-lipophilicity relationships of peptides and peptidomimetics

Summary Understanding the physicochemical and structural properties of peptides are important prerequisites for the rational design of bioactive peptides and peptidomimetics. The present contribution reviews methods used for the assessment and prediction of lipophilicity (or hydrophobicity) and their correlation with structural elements of peptides and closely related peptidomimetics.     

The influence of postnatal nutrition on lipoprotein lipase activity and hormone sensitive lipolysis in vitro of rat adipose tissue

In rats grown up in small and large nests the lipolytic activity of adipose tissue was studied in vitro in dependence on age. Independent of age and sex a significantly higher lipoprotein lipase activity as well as a lower basal or norepinephrine stimulated lipolysis and reesterification (absolute) occurred in rats from small nests compared with rats from large nests. The calculated degree of reesterification was independent of the nest size, but decreased from 80% to 30% from one month to one year of age. The marked differences in the lipolytic activities of adipose tissue emphasize the distinct influence of the post-natal nutrition on metabolic functions in the later life and lead to the conclusion that the metabolism of adipose tissue of animals from small nests is directed towards a long-term increased storage of lipids.     

Effect of temperature on the protein and nucleic acid content of thermotolerant yeasts

Summary The effect of growth at 30°, 35° and 40° on the biomass yield and on the nucleic acid and protein content of twelve isolates of yeast has been studied. Although yields of 41.6% and a true protein content of 34% were obtained, each of the strains exhibited a lower yield and protein content at 40° than at the lower temperatures. Nucleic acid levels were also reduced at 40°.