Galaxy disruption in a halo of dark matter

The relics of disrupted satellite galaxies have been found around the Milky Way and Andromeda, but direct evidence of a satellite galaxy in the early stages of disruption has remained elusive. We have discovered a dwarf satellite galaxy in the process of being torn apart by gravitational tidal forces as it merges with a larger galaxy's dark matter halo. Our results illustrate the morphological transformation of dwarf galaxies by tidal interaction and the continued buildup of galaxy halos.     

Antagonistic interactions between honey bee bacterial symbionts and implications for disease

Background  

Honey bees, Apis mellifera, face many parasites and pathogens and consequently rely on a diverse set of individual and group-level defenses to prevent disease. One route by which honey bees and other insects might combat disease is through the shielding effects of their microbial symbionts. Bees carry a diverse assemblage of bacteria, very few of which appear to be pathogenic. Here we explore the inhibitory effects of these resident bacteria against the primary bacterial pathogen of honey bees, Paenibacillus larvae.     

Unsuccessful treatment of a horse with mandibular granulomatous osteomyelitis due to Halicephalobus gingivalis

An 8-year-old horse was presented with a submandibular swelling. Biopsy of the lesion indicated granulomatous osteomyelitis due to Halicephalobus gingivalis. In the absence of evidence of involvement of the central nervous system at the time of diagnosis, the horse was treated with ivermectin. Unfortunately, the horse did not survive.     

Effects of Different Management Practices on Stand Composition and Species Diversity in Subtropical Forests in Nepal: Implications of Community Participation in Biodiversity Conservation

In this article, we compared the structure, composition, and diversity of trees, shrubs and saplings, seedlings and herbaceous species of community- and government-managed forests in the lowlands of eastern Nepal. Results suggest that among the trees, the community forest was dominated by a single species, Shorea robusta. However, Shorea robusta and Terminalia myriocarpa were codominant in the government forest. Tree density and basal area were higher in the government forest, but shrub/sapling density and basal area were higher in the community forest, suggesting a positive effect of community management on tree regeneration. Overstory species assemblages showed an obvious compositional difference between the forests, but understory species assemblages were less obvious. Plot-level tree and shrub/sapling species richness was higher in the government forest than the community forest. However, seedling-herbaceous species richness was higher in the community forest. The dominance of Shorea robusta trees in the community forest suggests that people involved in managing forests may be more interested in a limited number of economically valuable species while removing less important trees. Such preferential management practices may increase resource heterogeneity within a forest and maintain species diversity in the understory. Thus, community participation in forest management should be encouraged, with guided management techniques and exercises, to achieve maximum forest recovery, provide sustainable ecosystem services, and maintain forest diversity.     

Managing city forests for or in spite of recreation? Perspectives of forest managers

This paper provides insights into foresters’ perceptions of forest recreation and its management. It is based on qualitative interviews with foresters in Berlin and the region of Stuttgart, Germany (N = 16). The results highlight the lack of strategic planning concerned with recreation management at both locations. Moreover, recreation management seems to depend mostly on the local forester in charge. Foresters’ perceptions of recreation, in turn, appear to be closely linked with how they perceive their work. Three narratives of the foresters’ self-perception are constructed that address three key items: perception of foresters’ skills and tasks, perception of the societal and political context of the foresters’ work and of their own scope of action in this context, and visions for future recreation management. The first narrative emphasises classical forestry and silvicultural aspects; the second understands foresters as multifunctional service providers for communal clients; and the last criticises the classical orientation of forestry and highlights new challenges for foresters in urban areas. These three views of recreation management in urban forests relate to classical forestry culture in different ways: either embodying this culture; differentiating from it; or adopting a new view which challenges this culture. Further research needs are discussed. The paper lastly argues for increased awareness of the importance of the social dimensions of forest management as one of the crucial future challenges for the forestry profession.     

Engineering of a tyrosol-producing pathway, utilizing simple sugar and the central metabolic tyrosine, in Escherichia coli

Metabolic engineering was applied to the development of Escherichia coli capable of synthesizing tyrosol (2-(4-hydroxyphenyl)ethanol), an attractive phenolic compound with great industrial value, from glucose, a renewable carbon source. In this strain, tyrosine, which was supplied not only from the culture medium but also from the central metabolism, was converted into tyrosol via three steps: decarboxylation, amine oxidation, and reduction. The engineered strain synthesized both tyrosol and 4-hydroxyphenylacetate (4HPA), but disruption of the endogenous phenylacetaldehyde dehydrogenase gene shut off 4HPA production and improved the production of tyrosol as a sole product. The engineered mutant strain was capable of producing 0.5 mM tyrosol from 1% (w/v) glucose during a 48 h shake flask cultivation.