An examination of Stone Age/Bronze Age adzes and axes of red deer (<Emphasis Type="Italic">Cervus elaphus</Emphasis> L.) antler from the Leine Valley,near Hannover

Red deer antler was, together with stone, one of the most important raw materials for tool manufacture in prehistoric times. Both the physical characteristics of this material and the manufacturing technology of antler tools are examined. The use of experimental tests and analytical studies of the recovered antler finds allow us to propose, with a great degree of confidence, that the main use of antler axes during the Stone Age/Bronze Age was in woodworking.     

Reactions in vitro of the DNA polymerase-primase from Xenopus laevis eggs. A role for ATP in chain elongation

A form of DNA polymerase alpha was purified several thousandfold from a protein extract of Xenopus laevis eggs. The enzyme effectively converts, in the presence of ribonucleoside triphosphates, a circular single-stranded phage fd DNA template into a double-stranded DNA form and, therefore, must be associated with a DNA primase. We first show by gel electrophoresis in the presence of sodium dodecyl sulfate that both enzymatic activities, DNA polymerase and primase, most probably reside on a greater than 100 000-Da subunit of the DNA polymerase holoenzyme. We then assayed the polymerase-primase at various template/enzyme ratios and found that the DNA complementary strand sections synthesized in vitro belong to defined size classes in the range of 600-2000 nucleotides, suggesting preferred start and/or stop sites on the fd DNA template strand. We show that the stop sites coincide with stable hairpin structures in fd DNA. We have used a fd DNA template, primed by a restriction fragment of known size, to show that the polymerase-primase stops at the first stable hairpin structure upstream from the 3'-OH primer site when the reaction was carried out at 0.1 mM ATP. However, at 2 mM ATP the enzyme was able to travers this and other stop sites on the fd DNA template strand leading to the synthesis of 2-4 times longer DNA strands. Our results suggest a role for ATP in the polymerase-primase-catalyzed chain-elongation reaction.     

Complete genome sequence of the bacteriochlorophyll a-containing Roseibacterium elongatum type strain (DSM 19469T), a representative of the Roseobacter group isolated from Australian coast sand

Roseibacterium elongatum Suzuki et al. 2006 is a pink-pigmented and bacteriochlorophyll a-producing representative of the Roseobacter group within the alphaproteobacterial family Rhodobacteraceae. Representatives of the marine ‘Roseobacter group’ were found to be abundant in the ocean and play an important role in global and biogeochemical processes. In the present study we describe the features of R. elongatum strain OCh 323^T together with its genome sequence and annotation. The 3,555,102 bp long genome consists of one circular chromosome with no extrachromosomal elements and is one of the smallest known Roseobacter genomes. It contains 3,540 protein-coding genes and 59 RNA genes. Genome analysis revealed the presence of a photosynthetic gene cluster, which putatively enables a photoheterotrophic lifestyle. Gene sequences associated with quorum sensing, motility, surface attachment, and thiosulfate and carbon monoxide oxidation could be detected. The genome was sequenced as part of the activities of the Transregional Collaborative Research Centre 51 (TRR51) funded by the German Research Foundation (DFG).     

Pectinases in Aqueous Extracts of Ditylenchus dipsaci

Aqueous extracts of a population of Ditylenchus dipsaci isolated from onion and maintained monoxenically on onion callus contained endo-polygalacturonase (endo-PG) and endo-pectinmethyltranseliminase (endo-PMTE). In viscometric tests pH 4.2 and 4.0 were optimal for degradation of sodium polypectate and pectin N.F., respectively, by endo-PG. Endo-PMTE reduced viscosity of pectin N.F. optimally at pH 8.5 or above. Activity was dependent on CaCl₂. Pectinmethylesterase activity was not detected in water, NaCl, or sucrose extracts of these nematodes. The extracts macerated potato tuber tissue, onion cotyledonary tissue, and strips of onion epidermis from the ventral surface of onion bulb scales at pH 4.2, 5.3, and 6.2. Pectin could not be localized with hydroxylamine-ferric chloride reagent in macerated tissues treated for 24 hr with active extract.     

Construction and Rescue of a Molecular Clone of Deformed Wing Virus (DWV)

European honey bees are highly important in crop pollination, increasing the value of global agricultural production by billions of dollars. Current knowledge about virulence and pathogenicity of Deformed wing virus (DWV), a major factor in honey bee colony mortality, is limited. With this study, we close the gap between field research and laboratory investigations by establishing a complete in vitro model for DWV pathogenesis. Infectious DWV was rescued from a molecular clone of a DWV-A genome that induces DWV symptoms such as crippled wings and discoloration. The expression of DWV proteins, production of infectious virus progeny, and DWV host cell tropism could be confirmed using newly generated anti-DWV monoclonal antibodies. The recombinant RNA fulfills Koch’s postulates circumventing the need of virus isolation and propagation of pure virus cultures. In conclusion, we describe the development and application of a reverse genetics system for the study of DWV pathogenesis.     

Biotransformation and reduction of estrogenicity of bisphenol A by the biphenyl-degrading Cupriavidus basilensis

The biphenyl-degrading Gram-negative bacterium Cupriavidus basilensis (formerly Ralstonia sp.) SBUG 290 uses various aromatic compounds as carbon and energy sources and has a high capacity to transform bisphenol A (BPA), which is a hormonally active substance structurally related to biphenyl. Biphenyl-grown cells initially hydroxylated BPA and converted it to four additional products by using three different transformation pathways: (a) formation of multiple hydroxylated BPA, (b) ring fission, and (c) transamination followed by acetylation or dimerization. Products of the ring fission pathway were non-toxic and all five products exhibited a significantly reduced estrogenic activity compared to BPA. Cell cultivation with phenol and especially in nutrient broth (NB) resulted in a reduced biotransformation rate and lower product quantities, and NB-grown cells did not produce all five products in detectable amounts. Thus, the question arose whether enzymes of the biphenyl degradation pathway are involved in the transformation of BPA and was addressed by proteomic analyses.

     

Excision of an unstable pathogenicity island in Salmonella enterica serovar Enteritidis is induced during infection of phagocytic cells

The availability of the complete genome sequence of several Salmonella enterica serovars has revealed the presence of unstable genetic elements in these bacteria, such as pathogenicity islands and prophages. This is the case of Salmonella enterica serovar Enteritidis (S. Enteritidis), a bacterium that causes gastroenteritis in humans and systemic infection in mice. The whole genome sequence analysis for S. Enteritidis unveiled the presence of several genetic regions that are absent in other Salmonella serovars. These regions have been denominated "regions of difference" (ROD). In this study we show that ROD21, one of such regions, behaves as an unstable pathogenicity island. We observed that ROD21 undergoes spontaneous excision by two independent recombination events, either under laboratory growth conditions or during infection of murine cells. Importantly, we also found that one type of excision occurred at higher rates when S. Enteritidis was residing inside murine phagocytic cells. These data suggest that ROD21 is an unstable pathogenicity island, whose frequency of excision depends on the environmental conditions found inside phagocytic cells.