Determination of taxonomic resolution capacity of conventional one-dimensional SDS-polyacrylamide gel electrophoresis of whole-cell proteins using Enterobacteriaceae

The capacity of one-dimensional SDS-PAGE of whole bacterial cells to both separate and cluster taxonomic units is studied using members of Enterobacteriaceae as test material. The results show that intraspecies variation can be detected and on the other hand the degree of taxonomic divergence which still can be grouped together is determined. In addition the system has high tolerance to changes in cell culture conditions making the usage of SDS-PAGE suitable for applications where rapid and reliable bacterial identification is needed.     

Chloroplast DNA variation inAnemone s. lato (Ranunculaceae)

Chloroplast DNA of seven species belonging toAnemone (sectt.Omalocarpus, Anemonidium, andAnemonanthea),Hepatica, andPulsatilla have been analyzed by restriction enzymes. According to the dendrogram constructed, the sections ofAnemone and the generaHepatica andPulsatilla seem to be evolutionary approximately equidistant to each others. This supports the concept that these groups should be treated on a similar taxonomic level, either as genera or subgenera.     

Demonstration of PGl2 production by isolated perfused rat lungs with platelet aggregation test

Platelet aggregation test was used for PGl₂ measurements. The use of 6 % CO₂ in air stabilized human platelet rich plasma (PRP) so that it could be used for up to 7 hours in these measurements. The PGl₂ caused inhibition of aggregation in response to ADP was concentration dependent in the range of 0.5 ng/ml to 50 ng/ml. Isolated perfused rat lungs released spontaneously 190 ng/min PGl₂ and about 3 % of infused arachidonic acid potassium salt (equivalent to 25 μg/min arachidonic acid) was converted to PGl₂.     

Selection for outbreeding in Varroa parasitising resistant honey bee (Apis mellifera) colonies

Parasitism is expected to select for counter‐adaptations in the host: driving a coevolutionary arms race. However, human interference between honey bees (Apis mellifera) and Varroa mites removes the effect of natural selection and restricts the evolution of host counter‐adaptations. With full‐sibling mating common among Varroa, this can rapidly select for virulent, highly inbred, Varroa populations. We investigated how the evolution of host resistance could affect the infesting population of Varroa mites. We screened a Varroa‐resistant honey bee population near Toulouse, France, for a Varroa resistance trait: the inhibition of Varroa's reproduction in drone pupae. We then genotyped Varroa which had co‐infested a cell using microsatellites. Across all resistant honey bee colonies, Varroa's reproductive success was significantly higher in co‐infested cells but the distribution of Varroa between singly and multiply infested cells was not different from random. While there was a trend for increased reproductive success when Varroa of differing haplotypes co‐infested a cell, this was not significant. This suggests local mate competition, through the presence of another Varroa foundress in a pupal cell, may be enough to help Varroa overcome host resistance traits; with a critical mass of infesting Varroa overwhelming host resistance. However, the fitness trade‐offs associated with preferentially co‐infesting cells may be too high for Varroa to evolve a mechanism to identify already‐infested cells. The increased reproductive success of Varroa when co‐infesting resistant pupal cells may act as a release valve on the selective pressure for the evolution of counter resistance traits: helping to maintain a stable host–parasite relationship.     

Adaptive genetic diversity of trees for forest conservation in a future climate: a case study on Norway spruce in Austria

Genetic resources of forest trees are considered as a key factor for the persistence of forest ecosystems because the ability of tree species to survive under changing climate depends strongly on their intraspecific variation in climate response. Therefore, utilizing available genetic variation in climate response and planting alternative provenances suitable for future climatic conditions is considered as an important adaptation measure for forestry. On the other hand, the distribution of adaptive genetic diversity of many tree species is still unknown and the predicted shift of ecological zones and species’ distribution may threaten forest genetic resources that are important for adaptation. Here, we use Norway spruce in Austria as a case study to demonstrate the genetic variation in climate response and to analyse the existing network of genetic conservation units for its effectiveness to safeguard the hotspots of adaptive and neutral genetic diversity of this species. An analysis of the climate response of 480 provenances, clustered into 9 groups of climatically similar provenances, revealed high variation among provenance groups. The most productive and promising provenance clusters for future climates originate from three regions that today depict the warmest and driest areas of the natural spruce distribution in Austria. Gap analysis of the Austrian genetic conservation units in the EUFGIS Portal suggests adequate coverage of the genetic hotspots in southern parts of Austria, but not in eastern and northern Austria. Therefore conservation measures and sustainable utilization of the valuable genetic resources in these regions need to be expanded to cover their high adaptive genetic variation and local adaptation to a warmer climate. The study shows that current conservation efforts need to be evaluated for their effectiveness to protect genetic resources that are important for the survival of trees in a future climate.     

A gene for resistance to the Varroa mite (Acari) in honey bee (Apis mellifera) pupae

Social insect colonies possess a range of defences which protect them against highly virulent parasites and colony collapse. The host–parasite interaction between honey bees (Apis mellifera) and the mite Varroa destructor is unusual, as honey bee colonies are relatively poorly defended against this parasite. The interaction has existed since the mid‐20th Century, when Varroa switched host to parasitize A. mellifera. The combination of a virulent parasite and relatively naïve host means that, without acaricides, honey bee colonies typically die within 3 years of Varroa infestation. A consequence of acaricide use has been a reduced selective pressure for the evolution of Varroa resistance in honey bee colonies. However, in the past 20 years, several natural‐selection‐based breeding programmes have resulted in the evolution of Varroa‐resistant populations. In these populations, the inhibition of Varroa's reproduction is a common trait. Using a high‐density genome‐wide association analysis in a Varroa‐resistant honey bee population, we identify an ecdysone‐induced gene significantly linked to resistance. Ecdysone both initiates metamorphosis in insects and reproduction in Varroa. Previously, using a less dense genetic map and a quantitative trait loci analysis, we have identified Ecdysone‐related genes at resistance loci in an independently evolved resistant population. Varroa cannot biosynthesize ecdysone but can acquire it from its diet. Using qPCR, we are able to link the expression of ecdysone‐linked resistance genes to Varroa's meals and reproduction. If Varroa co‐opts pupal compounds to initiate and time its own reproduction, mutations in the host's ecdysone pathway may represent a key selection tool for honey bee resistance and breeding.     

alpha 2,3-Sialylation of terminal GalNAc beta 1-3Gal determinants by ST3Gal II reveals the multifunctionality of the enzyme. The resulting Neu5Ac alpha 2-3GalNAc linkage is resistant to sialidases from Newcastle disease virus and Streptococcus pneumoniae

Enzymatic alpha 2,3-sialylation of GalNAc has not been described previously, although some glycoconjugates containing alpha 2,3-sialylated GalNAc residues have been reported. In the present experiments, recombinant soluble alpha 2,3-sialyltransferase ST3Gal II efficiently sialylated the X(2) pentasaccharide GalNAc beta 1-3Gal beta 1-4GlcNAc beta 1-3Gal beta 1-4Glc, globo-N-tetraose GalNAc beta 1-3Gal alpha 1-4Gal beta 1-4Glc, and the disaccharide GalNAc beta 1-3Gal in vitro. The purified products were identified as Neu5Ac alpha 2-3GalNAc beta 1-3Gal beta 1-4GlcNAc beta 1-3Gal beta 1-4Glc, Neu5Ac alpha 2-3GalNAc beta 1-3Gal alpha 1-4Gal beta 1-4Glc, and Neu5Ac alpha 2-3GalNAc beta 1-3Gal, respectively, by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, enzymatic degradations, and one- and two-dimensional NMR-spectroscopy. In particular, the presence of the Neu5Ac alpha 2-3GalNAc linkage was firmly established in all three products by a long range correlation between Neu5Ac C2 and GalNAc H3 in heteronuclear multiple bond correlation spectra. Collectively, the data describe the first successful sialyltransfer reactions to the 3-position of GalNAc in any acceptor. Previously, ST3Gal II has been shown to transfer to the Gal beta 1-3GalNAc determinant. Consequently, the present data show that the enzyme is multifunctional, and could be renamed ST3Gal(NAc) II. In contrast to ST3Gal II, ST3Gal III did not transfer to the X(2) pentasaccharide. The Neu5Ac alpha 2-3GalNAc linkage of sialyl X(2) was cleaved by sialidases from Arthrobacter ureafaciens and Clostridium perfringens, but resisted the action of sialidases from Newcastle disease virus and Streptococcus pneumoniae. Therefore, the latter two enzymes cannot be used to differentiate between Neu5Ac alpha 2-3GalNAc and Neu5Ac alpha 2-6GalNAc linkages, as has been assumed previously.