<Emphasis Type="Italic">Burkholderia</Emphasis> Hep_Hag autotransporter (BuHA) proteins elicit a strong antibody response during experimental glanders but not human melioidosis

Background  

The bacterial biothreat agents Burkholderia mallei and Burkholderia pseudomallei are the cause of glanders and melioidosis, respectively. Genomic and epidemiological studies have shown that B. mallei is a recently emerged, host restricted clone of B. pseudomallei.     

Vegetation shifts towards wetter site conditions on oceanic ombrotrophic bogs in southwestern Sweden

Question: Is ombrotrophic bog vegetation in an oceanic region of southwestern Sweden changing in the same direction over a five year period (1999 ‐ 2004) as northwest European bogs in the last 50 years, i.e. towards drier and more eutrophic vegetation? Location: The province of Halland, southwestern Sweden. Methods: Changes in species composition were monitored in 750 permanently marked plots in 25 ombrotrophic bogs from 1999 to 2004. Changes in species occurrences and richness were analysed and a multivariate statistical method (DCA) was used to analyse vegetation changes. Results: The species composition changed towards wetter rather than drier conditions, which is unlike the general pattern of vegetation change on bogs in northwestern Europe. Species typical of wetter site conditions including most Sphagnum species increased in abundance on the bogs until 2004. The total number of species per plot increased, mostly due to the increased species richness of Sphagnum species. Nitrogen‐demanding (eutrophic) species increased in occurrence. Conclusions: Ombrotrophic bog vegetation in an oceanic region in Sweden became wetter and was resilient to short‐term climatic shifts, after three years of below normal precipitation followed by several years with normal precipitation levels. Shifts towards more nitrogen demanding species were rapid in this region where the deposition levels have been high for several decades.     

A note on light preference in layer pullets reared in incandescent or natural light

The effect of early exposure of pullets to natural light may have an effect on the later preference for light type and on the behaviour of birds after being transferred to laying facilities. Our aim was to study the light-type preference of 14-week pullets reared in either incandescent or natural light. From day-old, a total of 84 LSL chicks were subjected to two light treatments with six groups of seven birds each: 8 h incandescent light + 16 h darkness (I8), and 8 h natural light + 16 h darkness (N8). At the age of 14 weeks, the birds’ light-type preference was tested. Behaviour was recorded at the group level and analysed by a linear mixed model. Predicted mean proportion of birds that chose natural light was 0.36 in N8 and 0.13 in I8 groups. I8 groups showed a preference for incandescent light, in contrast to N8. These results support the notion that pullets for organic egg production shall be reared with access to natural light.     

Variable Female Mating Positions and Offspring Sex Ratio in the Spider Pityohyphantes phrygianus (Araneae: Linyphiidae)

Chromosomal sex determination and male heterogamety have been thought to seriously impede direct sex ratio control. However, in Pityohyphantes phrygianus, a solitary sheetweb spider with a skewed sex ratio, earlier experimental studies suggested that there are options for female control of offspring sex ratio, if females change their position during the normal mating sequence. Here we show that under natural conditions there is considerable between-female variation in positions, especially after termination of mating. Computer simulations of the orientation of female inner genitalia suggest that sperm are placed in different storage sites depending on the positions adopted. This means that a specific position after mating might potentially influence offspring sex ratio. The variance in offspring sex ratio among females in earlier experiments was binomially distributed, which leads us to conclude that females control the mean sex ratio but do not exercise direct control of the sex of individual offspring.     

Cultural and Biochemical Characteristics of Mycobacterium Paratuberculosis Isolated from Goats in Norway

In Norway a variant of Mycobacterium paratuberculosis occurs which causes disease in goats but very seldom in sheep and cattle. Cultural and biochemical characteristics of this variant are investigated by comparing different pre-treatment methods and culture media for primary isolation and by subjecting a number of strains to different enzymatic and biochemical tests. Decontamination of materials with 5% oxalic acid and 0.1% benzalkonium chloride and culture on Dubos, Finleyson’s and Herrold’s medium was tested. The investigations showed that the combination oxalic acid decontamination/Dubos’ medium is most suitable for isolation of the goat-pathogenic variant. The morphology of the colonies was also most easily studied after culture on Dubos’ medium from material pre-treated with oxalic acid. The biochemical tests were found to be poorly suitable for the identification of M. paratuberculosis and for its differentiation from other mycobacteria. Mycobactin dependence for growth seems not to be absolute as a few goat strains produced growth on Dubos’ medium without mycobactin. However, growth was in all cases far better in the presence of mycobactin.     

Oak leaves as aerosol collectors: relationships with wind velocity and particle size distribution. Experimental results and their implications

Advancing the understanding of the aerosol-capture efficiencies of forest components such as leaves and needles, and of the mechanisms that underpin these efficiencies, is essential to the many related issues of forest turnover of nutrients and pollutants. For idealized collectors (such as artificial plates or cylinders) aerosol-mechanics offers a means for calculating capture efficiencies. For living collectors, in particular deciduous leaves, experimental investigations become necessary to assist in formulating the sub-models of capture efficiency that are fundamental to the modelling of fluxes of aerosol-borne substances to forests. We here present wind-tunnel based methods and results for leaves of Quercus robur L. exposed to an aerosol whose mass versus aerodynamic particle size distribution is characterised by a geometric mean aerodynamic particle diameter around 1.2 μm and a geometric standard deviation around 1.8. With respect to that distribution, and founded on a specially designed leaf wash-off method, we obtained average oak-leaf capture efficiencies ranging from 0.006% of the approaching aerosol mass flux at wind-speed 2 ms⁻¹ to 0.012% of the flux at wind-speeds 10 ms⁻¹, respectively. These values can be translated into deposition velocities (V _d ) for a leaf ensemble with a given leaf area index (LAI). With LAI in the range 2–5 (commonly found in the field) and for wind-speeds 2, 5 and 10 ms⁻¹, resulting V _d -values would be 0.02–0.05, 0.05–0.13, and 0.2–0.6 cm/s, respectively. To the extent comparisons are possible, our capture efficiency values are at the low end of the range of values reported by other researchers. The strong wind-speed sensitivity of V _d has implications for the deposition of aerosol-borne substances to forests for which wind regimes may shift as a result of climatic and land-use changes.     

Effects of pair migratory behavior on breeding phenology and success in a partially migratory shorebird population

In migratory systems, variation in individual phenology can arise through differences in individual migratory behaviors, and this may be particularly apparent in partial migrant systems, where migrant and resident individuals are present within the same population. Links between breeding phenology and migratory behavior or success are generally investigated at the individual level. However, for breeding phenology in particular, the migratory behaviors of each member of the pair may need to be considered simultaneously, as breeding phenology will likely be constrained by timing of the pair member that arrives last, and carryover effects on breeding success may vary depending on whether pair members share the same migratory behavior or not. We used tracking of marked individuals and monitoring of breeding success from a partially migrant population of Eurasian oystercatchers (Haematopus ostralegus) breeding in Iceland to test whether (a) breeding phenology varied with pair migratory behavior; (b) within‐pair consistency in timing of laying differed among pair migratory behaviors; and (c) reproductive performance varied with pair migratory behavior, timing of laying, and year. We found that annual variation in timing of laying differed among pair migratory behaviors, with resident pairs being more consistent than migrant and mixed pairs, and migrant/mixed pairs breeding earlier than residents in most years but later in one (unusually cold) year. Pairs that laid early were more likely to replace their clutch after nest loss, had higher productivity and higher fledging success, independent of pair migratory behavior. Our study suggests that the links between individual migratory behavior and reproductive success can vary over time and, to a much lesser extent, with mate migratory behavior and can be mediated by differences in laying dates. Understanding these cascading effects of pair phenology on breeding success is likely to be key to predicting the impact of changing environmental conditions on migratory species.     

<Emphasis Type="Italic">Leptospira</Emphasis> seroprevalence and associations between seropositivity,clinical disease and host factors in horses

Background  

A cross-sectional study was carried out to determine the seroprevalence of different serovars of Leptospira spp. and their association with clinical disease and host factors in Swedish horses.