Foraging in ants is generally organized along well-defined trails supporting a bi-directional flow of outbound and nestbound individuals and one can hypothesize that this flow is maximized to ensure a high rate of food return to the nest. In this paper we examine the effect of bottlenecks on the temporal organization of ant flow. In our experiments ants had to cross a bridge to go from their ne...

Two stereospecific NADPH-dependent reductases, TR-I and TR-11, constitute a branching point in the biosynthesis of tropane alkaloids. TR-I catalyzes the stereospecific reduction of tropinone to tropine (Koelen and Gross, 1982), whereas TR-I1 reduces tropinone to pseudotropine (Drager et al., 1988). We previously characterized TRs that had been purified from cultured roots of Hyoscyamus niger (H...

A rhamnogalacturonan hydrolase gene of Aspergillus aculeatus was used as a probe for the cloning of two rhamnogalacturonan hydrolase genes of Aspergillus niger. The corresponding proteins, rhamnogalacturonan hydrolases A and B, are 78 and 72% identical, respectively, with the A. aculeatus enzyme. In A. niger cultures which were shifted from growth on sucrose to growth on apple pectin as a carbo...

various plant organ segments including segments from roots (root tip, and root collar), stems, leaves, and also seeds of several hyoscyamus species (i.e. h. pusillus, h. arachnoideus, annual and biennial h. niger from two distinct geographical regions) were cultured on ms media with various growth regulator combinations, to assess the ability of flower production. statistical assessments showed...

We demonstrate a new sensitive biosensor for detection of vital fungal spores of Aspergillus niger. The biosensor is based on silicon microfabricated cantilever arrays operated in dynamic mode. The change in resonance frequency of the sensor is a function of mass binding to the cantilever surface. For specific A. niger spore immobilization on the cantilever, each cantilever was individually coa...

Representatives of the genus Aspergillus are opportunistic fungal pathogens. Their conidia can reach the alveoli by inhalation and can give rise to infections in immunocompromised individuals. Aspergillus fumigatus is the causal agent of invasive aspergillosis in nearly 90% of the cases. It is not yet well-established what makes this fungus more pathogenic than other aspergilli such as A. niger...

Effects of Hyoscyamus niger L on central nervous system have been known for many years. The effects of methanolic extract of H. niger L. on seizures induced by picrotoxin was studied in mice in this investigation. In this study 7 groups of animals pretreated with methanolic extract of the plant (12.5, 25, 50, 100, 200, 300, 400 mg/kg/i.p.), 20 minutes prior to the picrotoxin (12 mg/kg/ i.p.)--i...