Assessment of the scalability of a microtiter plate system for screening of oleaginous microorganisms

Applied Microbiology and Biotechnology - Recent developments in molecular biology and metabolic engineering have resulted in a large increase in the number of strains that need to be tested,...     

The effect of tetramethylammonium on single sodium channel currents.

Voltage-dependent Na conductance of rat myotubes was studied by patch recordings of single-channels. The patches were excised from the cell with the patch electrode, and the cytoplasmic surface was bathed in either CsF or tetramethylammonium (TMA)-F. Inward currents were examined from -20 to -50 mV. In this range Cs and TMA both appeared to be nearly impermeant, but TMA blocked the channel in a voltage-dependent manner. A first-order blocking site was located a maximum of 89% of the way through the membrane field from the cytoplasmic surface.     

Common peptides shed light on evolution of Olfactory Receptors

Background  

Olfactory Receptors (ORs) form the largest multigene family in vertebrates. Their evolution and their expansion in the vertebrate genomes was the subject of many studies. In this paper we apply a motif-based approach to this problem in order to uncover evolutionary characteristics.     

A Late Holocene Pollen and Charcoal Record from La Selva Biological Station, Costa Rica

Pollen and charcoal analysis of a 5.9-m-long sediment profile from a swamp on an alluvial terrace on the edge of La Selva biological station, Costa Rica (10°26'23" N, 84°00'24" W, 36 m asl), documents three millennia of human and natural disturbance within a lowland tropical rain forest. The record indicates that the highly diverse rain forest that presently surrounds the Cantarrana swamp regrew following forest clearing and maize agriculture that ended only a few centuries ago. The first maize pollen appears in sediments deposited ∼1070 calendar-year BP. Older sediments below the 'maize zone' contain macroscopic charcoal, abundant microscopic charcoal, and possible pollen indicators of forest clearance, perhaps signaling local cultivation of root crops that left no pollen in the sediments. Interpretation of local archaeology indicates that La Selva reserve may have been most heavily populated during the El Bosque and La Selva regional archaeological phases from 2250–950 yr BP. However, the distribution of maize pollen in the sediments is clear evidence that the reserve was also occupied during the later La Cabaña phase (950–400 yr BP), from which few artifacts have yet surfaced. Natural forest disturbance from treefalls and stream dynamics, and hydrological shifts associated with late-Holocene climate variability, form a backdrop to the human land-use history preserved in the Cantarrana sediment profile.     

Spatial dynamics of rotifers in a large lowland river,the Elbe,Germany: How important are retentive shoreline habitats for the plankton community?

A stable nitrogen isotope analysis was used to clarify the relative importance of denitrification and nitrate uptake by plants in the nitrate reduction in a reed belt of L. Kamisagata (N 37°49′, E 138°53′, alt. 4.5 m, depth 30–80 cm, area 0.025 km²), one of about 20 sand dune lakes in Japan. A very high concentration of NO ₃ ⁻ -N with 19.0 ± 5.9 mg N l⁻¹ in spring sources decreased during passage through the reed belt along two set transect lines about 120 m long in any season, whereas progressive enrichment in ¹⁵N-NO ₃ ⁻ in flowing water was detected. Loss rate of nitrate ranged from 38.4 to 73.1% with an average of 56.7 ± 11.6%. Enrichment factors calculated using a Rayleigh curve method ranged from −1.03 to −5.12‰. The contribution of denitrification to nitrate loss ranged from 6 to 28%, with a mean of 19.5% (±7.0), whereas that of plant uptake was from 72 to 94%, with a mean of 80.5% (±7.0), indicating the importance of vegetation in a sand dune riparian zone. A technique using the variation of natural abundance of ¹⁵N may provide useful information on the nitrate dynamics in artificial or natural wetlands under a non-destructive condition.