Outside St. Jørgen: leprosy in the medieval Danish city of Odense

Leprosy was a common and dreaded disease in the Danish Middle Ages (AD 1050-1536). Starting in the second half of the 13th century, leprosaria were established in many Danish towns and cities. In the city of Odense (on the island of Funen, Denmark), the cemetery of the leprosarium was totally excavated, and four nonleprosarium medieval and early modern cemeteries have been partly excavated. This paper explores the frequency of leprosy in the nonleprosarium cemeteries in Odense, and looks for evidence of selective exclusion from the ordinary population. The analyses are based on 733 skeletons from four cemeteries in Odense: the Gray Friars monastery, St. Albani parish church, St. Knuds cathedral, and Black Friars monastery. Seven lesions are scored and, based on known epidemiological properties (i.e., specificity and sensitivity) of these lesions, scores were transformed to statistics characterizing an individual's risk of having suffered from leprosy. This statistical approach remains of primary theoretical value, pending confirmation by independent research groups at other sites. Prevalence of the skeletal manifestation of leprosy at death varied between 0-17% among the different cemeteries in Odense. The highest prevalence was seen in cemeteries with many burials before AD 1400. It is estimated that before AD 1400, between 14-17% of those buried in the nonleprosarium cemeteries suffered from leprosy. In all nonleprosarium cemeteries, there was evidence for selective exclusion of people with facial leprosy lesions. For a short period just up to AD 1300, the cemetery of the Odense leprosarium had, on average, more than 20 yearly burials. The establishment of the leprosarium was followed within a relatively short period by a dramatic decline in the number of sufferers of leprosy in the nonleprosarium cemeteries. The number of yearly burials in the leprosarium cemetery also declined rapidly during the 14th century. The present analyses do not permit conclusions about the reasons for this decline in leprosy prevalence.     

Regulation of Bacterioplankton Production and Cell Volume in a Eutrophic Estuary

During three periods of 16 to 25 days, bacterioplankton production, bacterial cell volume, chlorophyll a, CO₂ assimilation, and particulate organic carbon were measured in enclosures situated in the eutrophic estuary Roskilde Fjord, Denmark. The enclosures were manipulated with respect to sediment contact and contents of inorganic nutrients, planktivorous fish, and suspension-feeding bivalves. Nutrient enrichment, the presence of suspension feeders, and sediment contact induced pronounced changes in bacterial production, as well as minor changes in bacterial cell volume; however, these effects seemed to be indirect, transmitted via phytoplankton. Bacterial production, measured as [³H]thymidine incorporation, closely followed changes in phytoplankton biomass and production, with time lags of 5 to 10 days. Good correlations of mean bacterioplankton production to chlorophyll a concentration and CO₂ assimilation suggested phytoplankton to be the dominating source of bacterial substrate, apparently independent of nutrient stress. Zooplankton >140 μm, bivalves, and sediment seemed to provide insignificant, if any, substrate for bacterioplankton, and benthic suspension feeders seemed not to act as direct competitors for dissolved organic carbon. The bacterioplankton mean cell volume, measured by image analysis, changed seasonally, with the smallest cells during the summer. Within each period, the bacterial cell volume correlated positively to growth rate and negatively to temperature.     

Solution structure of a dsDNA:LNA triplex

We have determined the NMR structure of an intramolecular dsDNA:LNA triplex, where the LNA strand is composed of alternating LNA and DNA nucleotides. The LNA oligonucleotide binds to the dsDNA duplex in the major groove by formation of Hoogsteen hydrogen bonds to the purine strand of the duplex. The structure of the dsDNA duplex is changed to accommodate the LNA strand, and it adopts a geometry intermediate between A- and B-type. There is a substantial propeller twist between base-paired nucleobases. This propeller twist and a concomitant large propeller twist between the purine and LNA strands allows the pyrimidines of the LNA strand to interact with the 5′-flanking duplex pyrimidines. Altogether, the triplex has a regular global geometry as shown by a straight helix axis. This shows that even though the third strand is composed of alternating DNA and LNA monomers with different sugar puckers, it forms a seamless triplex. The thermostability of the triplex is increased by 19°C relative to the unmodified DNA triplex at acidic pH. Using NMR spectroscopy, we show that the dsDNA:LNA triplex is stable at pH 8, and that the triplex structure is identical to the structure determined at pH 5.1.     

Conference and workshop on modelling global land use implications in the environmental assessment of biofuels

Background, Aims and Scope  On 4–5 June 2007, an international conference was held in Copenhagen. It provided an interdisciplinary forum where economists and geographers met with LCA experts to discuss the challenges of modelling the ultimate land use changes caused by an increased demand for biofuels. Main Features  The main feature of the conference was the cross-breeding of experience from the different approaches to land use modelling: The field of LCA could especially benefit from economic modelling in the identification of marginal crop production and the resulting expansion of the global agricultural area. Furthermore, the field of geography offers insights in the complexity behind new land cultivation and practical examples of where this is seen to occur on a regional scale. Results  Results presented at the conference showed that the magnitude and location of land use changes caused by biofuels demand depend on where the demand arises. For instance, mandatory blending in the EU will increase land use both within and outside of Europe, especially in South America. A key learning for the LCA society was that the response to a change in demand for a given crop is not presented by a single crop supplier or a single country, but rather by responses from a variety of suppliers of several different crops in several countries. Discussion  The intensification potential of current and future crop and biomass production was widely discussed. It was generally agreed that some parts of the third world hold large potentials for intensification, which are not realised due to a number of barriers resulting in so-called yield gaps. Conclusions  Modelling the global land use implications of biofuels requires an interdisciplinary approach optimally integrating economic, geographical, biophysical, social and possibly other aspects in the modelling. This interdisciplinary approach is necessary but also difficult due to different perspectives and mindsets in the different disciplines. Recommendations and Perspectives  The concept of a location dependent marginal land use composite should be introduced in LCA of biofuels and it should be acknowledged that the typical LCA assumption of linear substitution is not necessarily valid. Moreover, fertiliser restrictions/accessibility should be included in land use modelling and the relation between crop demand and intensification should be further explored. In addition, environmental impacts of land use intensification should be included in LCA, the powerful concept of land use curves should be further improved, and so should the modelling of diminishing returns in crop production.     

Bias in the Listeria monocytogenes Enrichment Procedure: Lineage 2 Strains Outcompete Lineage 1 Strains in University of Vermont Selective Enrichments

Listeria monocytogenes can be isolated from a range of food products and may cause food-borne outbreaks or sporadic cases of listeriosis. L. monocytogenes is divided into three genetic lineages and 13 serotypes. Strains of three serotypes (1/2a, 1/2b, and 4b) are associated with most human cases of listeriosis. Of these, strains of serotypes 1/2b and 4b belong to lineage 1, whereas strains of serotype 1/2a and many other strains isolated from foods belong to lineage 2. L. monocytogenes is isolated from foods by selective enrichment procedures and from patients by nonselective methods. The aim of the present study was to investigate if the selective enrichment procedure results in a true representation of the subtypes of L. monocytogenes present in a sample. Eight L. monocytogenes strains (four lineage 1 strains and four lineage 2 strains) and one Listeria innocua strain grew with identical growth rates in the nonselective medium brain heart infusion (BHI), but differed in their growth rate in the selective medium University of Vermont medium I (UVM I). When coinoculated in UVM I, some strains completely outgrew other strains. This outcome was dependent on the lineage of L. monocytogenes rather than the individual growth rate of the strains. When inoculated at identical cell densities in UVM I, L. innocua outcompeted L. monocytogenes lineage 1 strains but not lineage 2 strains. In addition, lineage 2 L. monocytogenes strains outcompeted lineage 1 L. monocytogenes strains in all combinations tested, indicating a bias in strains selected by the enrichment procedures. Bias also occurred when coinoculating two lineage 2 or lineage 1 strains; however, it did not appear to correlate with origin (clinical versus food). Identical coinoculation experiments in BHI suggested that the selective compounds in UVM I and II influenced this bias. The results of the present study demonstrate that the selective procedures used for isolation of L. monocytogenes may not allow a true representation of the types present in foods. Our results could have a significant impact on epidemiological studies, as lineage 1 strains, which are often isolated from clinical cases of listeriosis, may be suppressed during enrichment by other L. monocytogenes lineages present in a food sample.     

Soil–atmosphere exchange of N2O, CO2 and CH4 along a slope of an evergreen broad-leaved forest in southern China

At most sites the magnitude of soil-atmosphere exchange of nitrous dioxide (N₂O), carbon dioxide (CO₂) and methane (CH₄) was estimated based on a few chambers located in a limited area. Topography has been demonstrated to influence the production and consumption of these gases in temperate ecosystems, but this aspect has often been ignored in tropical areas. In this study, we investigated spatial variability of the net fluxes of these gases along a 100 m long slope of a evergreen broadleaved forest in southern China over a whole year. We expected that the lower part of slope would release more N₂O and CO₂, but take up less atmospheric CH₄ than the upper part due to different availability of water and nutrients. Our results showed that the soil moisture (Water Filled Pore Space, WFPS) decreased along the slope from bottom to top as we expected, but among the three gases only N₂O emissions followed this pattern. Annual means of WFPS ranged from 27.7% to 52.7% within the slope, and annual emissions of N₂O ranged from 2.0 to 4.4 kg N ha^?1 year^?1, respectively. These two variables were highly and positively correlated across the slope. Neither potential rates of net N mineralization and nitrification, nor N₂O emissions in the laboratory incubated soils varied with slope positions. Soil CO₂ release and CH₄ uptake appeared to be independent on slope position in this study. Our results suggested that soil water content and associated N₂O emissions are likely to be influenced by topography even in a short slope, which may need to be taken into account in field measurements and modelling.     

An easy-to-handle semi-automated method for media development using a colorimetric viability assay and fractional factorial designs

A rapid and effective semi-automated screening method has been developed for the development of growth media for mammalian cell culture. The method has proven to be a powerful tool for preliminary evaluation and comparison of new media formulations, but has some inherent disadvantages, which are important to recognise in order to interpret the results.     

Antifungal 3-hydroxy fatty acids from Lactobacillus plantarum MiLAB 14

We report the identification and chemical characterization of four antifungal substances, 3-(R)-hydroxydecanoic acid, 3-hydroxy-5-cis-dodecenoic acid, 3-(R)-hydroxydodecanoic acid and 3-(R)-hydroxytetradecanoic acid, from Lactobacillus plantarum MiLAB 14. The concentrations of the 3-hydroxy fatty acids in the supernatant followed the bacterial growth. Racemic mixtures of the saturated 3-hydroxy fatty acids showed antifungal activity against different molds and yeasts with MICs between 10 and 100 micrograms ml-1.