Body muscles of the lamprey. Some structural features of the T system and sarcolemma

Electron microscopic studies confirm and extend the conclusions derived previously from a quantitative biochemical study of the phagocytosis of polystyrene and polyvinyltoluene latex beads by Acanthamoeba (1). Latex beads 1.305, 1.90, and 2.68 µ in diameter are ingested individually, with each bead tightly surrounded by a membrane derived from the plasma membrane. Latex beads 0.557, 0.264, 0.126, and 0.088 µ in diameter are accumulated at the surface of the ameba and then phagocytosed, with many beads tightly packed within one membrane-bounded vesicle.     

Möglichkeiten zur Steigerung der Schwermetallsorptionsleistung von Mikroorganismen

The sorption capacity of silver on different biological materials has been investigated depending on physico-chemical pretreatments. The maximum silver loading values measured were compared with the values obtained with nontreated biomasses. The results show an increase of the loading capacity up to a factor of 10 in case of the alkalitreated biomasses. When the biomasses are extracted before being used as adsorbent with a solvent mixture of chloroform/methanol in a ratio of 2:1 the efficiency of the silver adsorbing power can be increased. Beyond that, the ability to adsorb silver can also be influenced when microorganisms are used as biocatalysts in a product synthesis before they are used as adsorbents. A strain of Acetobacter methanolicus possesses 1.8 times higher affinity to silver when it is employed in a process of gluconic acid production before adsorption. Physico-chemical pretreatments influence not only the loading capacity of the biological material, but also the contacting time required for the establishment of the adsorption equilibrium can be considerable reduced.     

Zur Kinetik der Mischsubstratutilisation bei der Citronensäure-akkumulation durch Saccharomycopsis lipolytica EH 59

The mechanism and the kinetic of the assimilation of mixed substrates during the organism growth and the product excretion by strain of Saccharomycopsis lipolytica have been studied. The assimilation of citric acid for the organism growth was prevented when glucose and/or n-paraffins are present as substrates. Citric acid concentrations higher than 30 g/l in the fermentation medium decrease the growth rate on the substrate glucose. Kinetic studies of the mixed substrate assimilation by means of a n-tetradecane-1-C-labelled paraffin fraction proved that in discontinuous as well as in continuous 1-stage-processes for microbial production of citric acid glucose as substrate is only used for the organism growth whereas the n-paraffin fraction is only used for the acid excretion.     

Ein Laborkleinfermentorsystem für die biotechnologische Grundlagenforschungl—MTA-Ausrüstung

Laborfermentoren stellen ein grundlegendes Arbeitsmittel in der biotechnologischen Forschung dar, dessen Entwicklungsst and in entscheidendem Maße Leistungsfähigkeit und Effektivität der Forschungsprozesse bestimmt. Deshalb ist eng verbunden mit den stündig steigenden Anforderungen an Quantität und Qualität der Informationen aus den verschiedenen hierarchischen Niveaus biotechnologischer Prozesse die Entwicklung hoch instrumentierter leistungsfähiger Laborfermentorsyteme. Der Trend, biotechnologische Prozesse in ihrer Raum-Zeit-Ausbeute traditionellen chemischen Prozessen anzugleichen, führte zur Entwicklung von Fermentorsystemen mit neuen Wirkprinzipien zur Gewährleistung hoher Stoffäbertragungsleistungen. Mit der Realisierung derartiger Hochleistungsfermentoren in großtechnischen Dimensionen ist verbunden die Forderung nach leistungsfähigen Laborfermentoren für die Erarbeitung wissenschaftlicher Grundlagen als Basis für eine gesicherte Maßestabsäbertragung. Die Entwicklung eines 2,5 l Laborsterilfermentors mit hohen Stoffübertragungsleistungen stellt einen Beitrag zur Vervollständigung der gerätetechnischen Basis für die biotechnologische Grundlagenforschung dar.     

Interactions between spatially separated herbivores indirectly alter plant diversity

Above‐ and belowground herbivores promote plant diversity when selectively feeding on dominant plant species, but little is known about their combined effects. Using a model system, we show that neutral effects of an aboveground herbivore and positive effects of a belowground herbivore on plant diversity became profoundly negative when adding these herbivores in combination. The non‐additive effects were explained by differences in plant preference between the aboveground‐ and the belowground herbivores and their consequences for indirect interactions among plant species. Simultaneous exposure to aboveground‐ and belowground herbivores led to plant communities being dominated by a few highly abundant species. As above‐ and belowground invertebrate herbivores generally differ in their mobility and local distribution patterns, our results strongly suggest that aboveground–belowground interactions contribute to local spatial heterogeneity of diversity patterns within plant communities.