Long-term effects of sheep grazing on giant hogweed (Heracleum mantegazzianum)

A meadow dominated by a mature, flowering stand of Giant Hogweed (Heracleum mantegazzianum) was grazed by sheep in the years 1987–1993. After two years Giant Hogweed cover was much reduced and a typical meadow vegetation was established. By 1993 Giant Hogweed was completely eliminated though total species diversity was much reduced. Soil sampled from the grazed area developed no Giant Hogweed seedlings in a germination test and contained no viable seeds of the species. In contrast soil from adjacent stands produced numerous seedlings with a peak emergence from samples taken after the winter. Seeds collected in October showed a viability in tetrazolium test of 88%. Germination averaged 22% after storage at room temperature and 25% following three weeks treatment at –18°C. It was concluded that the persistence of Giant Hogweed seeds in Danish meadow soils is less than seven years.     

Borneo Illipe,a fat product from differentShorea spp. (Dipterocarpaceae)

Fat extracted from kernels of Shorea spp. (Dipterocarpaceae) in the tropical rainforests of Borneo and Sumatra are traded under the name Borneo Illipe. The fat is used in chocolate formulations. The majority of kernels collected are fromShorea species in the sectionPachycarpae. Fat characteristics ofShorea species in this section show differences in fat quality in relation to its use as exotic sources in Cocoa Butter Equivalent (CBE) formulations. In order to comment on the future potential of the naturally occurring tree populations distribution maps of fiveShorea spp. involved in Borneo Illipe utilization are presented.     

Cultivation of Lactococcus lactis in a polyelectrolyte-neutral polymer aqueous two-phase system

The possibility to cultivate Lactococcus lactis in aqueous polymer two-phase system has been investigated. The phase system was made up of poly(ethylene imine) and (hydroxyethyl) cellulose. Long lag phases were needed for the microorganism to adapt to the polymer rich media. Cells favoured the (hydroxyethyl)cellulose rich top phase or they accumulated at the interface, while lactic acid showed affinity for the poly(ethylene imine) rich phase.Abbreviations PEG poly(ethylene glycol) - PEI poly(ethylene imine) - HEC (hydroxyethyl)cellulose     

Application of radiationless energy transfer for distance measurements across membranes

For several 2- or 3-dimensional configurations of stationary donors and acceptors on or near a spherical membrane shell the transition probabilities for radiationless energy transfer are calculated, using Förster's approximation obtained for Coulombic dipole-dipole interaction of the transition moments. It turns out that the difference in the refractive indices for membrane (lipid) and bulk phase (water) has only a small influence on the transition probabilities. Furthermore, the curvature of biological cell surfaces can be neglected, but affects the energy transfer across small vesicles. The ratio thickness/radius of small vesicles can be determined by measuring fluorescence quenching of excited donors by acceptors on the other side of the membrane.     

Pattern of polypeptide synthesis in myoblast hybrids

We have examined cell hybrids derived from L6J1 rat myoblasts and A9 mouse fibroblastic cells for expression of the myogenic phenotype. Initial results showed that hybrid cells were no longer able to form myotubes and hence showed extinction of the myogenic phenotype. We then proceeded to characterize the pattern of protein synthesis in these cells using two-dimensional gel electrophoresis. Although we did detect extinction of synthesis of a small number of myoblast polypeptides in the hybrids these did not appear to be rat myoblast specific. Instead they correlated well with polypeptides lost upon viral transformation in another rat cell line. Analysis of the ability of parental cells and hybrids to grow in soft agar confirmed that both A9 cells and hybrids were more transformed than the parental L6J1 cells. The results are consistent with the interpretation that extinction of the ability to form myotubes is due to either transformation and/or a disrupted cell organization but is unlikely to be due to specific extinction of myoblast specific polypeptides, at least at the level detectable by 2D gel electrophoresis.     

Bidirectional C and N transfer and a potential role for sulfur in an epiphytic diazotrophic mutualism

In nitrogen-limited boreal forests, associations between feathermoss and diazotrophic cyanobacteria control nitrogen inputs and thus carbon cycling, but little is known about the molecular regulators required for initiation and maintenance of these associations. Specifically, a benefit to the cyanobacteria is not known, challenging whether the association is a nutritional mutualism. Targeted mutagenesis of the cyanobacterial alkane sulfonate monooxygenase results in an inability to colonize feathermosses by the cyanobacterium Nostoc punctiforme, suggesting a role for organic sulfur in communication or nutrition. Isotope probing paired with high-resolution imaging mass spectrometry (NanoSIMS) demonstrated bidirectional elemental transfer between partners, with carbon and sulfur both being transferred to the cyanobacteria, and nitrogen transferred to the moss. These results support the hypothesis that moss and cyanobacteria enter a mutualistic exosymbiosis with substantial bidirectional material exchange of carbon and nitrogen and potential signaling through sulfur compounds.Subject terms: Microbial ecology, Plant ecology, Biogeochemistry, Stable isotope analysis     

Integrated removal of nucleic acids and recovery of LDH from homogenate of beef heart by affinity precipitation

Lactate dehydrogenase (LDH) was purified from beef heart homogenate by affinity precipitation. The protein purification was integrated with nucleic acid removal and was done by precipitation of nucleic acids by addition of poly(ethylene imine) PEI onto which a ligand, Cibacron blue, had been coupled. The yield of LDH after elution from the precipitate was 63%, the purification factor 6.9 and the nucleic acid content was reduced by 98%. The capacity of the affinity polymer Cibacron blue-PEI is dependent on the nucleic acid concentration in the homogenate. The beef heart homogenate had an unfavourable ratio of nucleic acids to LDH. Precipitation with recirculated Cibacron blue-PEI, already complexed with some nucleic acids, improved the yield of the enzyme to 74%. The loss of Cibacron blue-PEI, when recirculated, was less than 1% after each cycle. This revised version was published online in July 2006 with corrections to the Cover Date.     

Ein Insekten-Exkrement aus Sporen aus dem unterkretazischen Saurierlager von Nehden (Sauerland,Westfalen)

Short preliminary report on excellently preserved vegetable microfossils, besides an insect excrement consisting of fern-spores, from the Lower Cretaceous Iguanodontidae locality of Nehden (Sauerland, Westphalia, FRG).