Uukuniemi Phlebovirus Assembly and Secretion Leave a Functional Imprint on the Virion Glycome

Uukuniemi virus (UUKV) is a model system for investigating the genus Phlebovirus of the Bunyaviridae. We report the UUKV glycome, revealing differential processing of the Gn and Gc virion glycoproteins. Both glycoproteins display poly-N-acetyllactosamines, consistent with virion assembly in the medial Golgi apparatus, whereas oligomannose-type glycans required for DC-SIGN-dependent cellular attachment are predominant on Gc. Local virion structure and the route of viral egress from the cell leave a functional imprint on the phleboviral glycome.     

Comparative analysis of amplified fragment length polymorphism and pulsed field gel electrophoresis in a hospital outbreak and subsequent endemicity of ampicillin-resistant Enterococcus faecium

Reliable molecular methods for determination of relatedness between bacterial isolates have become increasingly important to evaluate outbreaks and endemic situations with nosocomial pathogens. In the present study Simpson's index of diversity with calculated confidence intervals was used to compare amplified fragment length polymorphism (AFLP) and pulsed field gel electrophoresis (PFGE) analysis of a hospital outbreak of ampicillin-resistant Enterococcus faecium and subsequent endemicity. The outbreak, in a Norwegian tertiary hospital, of infections caused by these enterococci started in 1995 and increased in 1996 after which the situation turned endemic. The purpose of this study was to compare the two methods in this setting and to determine the length of time during an outbreak that these methods are sufficiently valid to be of value for hospital infection control efforts. One hundred and sixty clinical isolates from urine specimens collected during the period 1995-1999 were included. The findings indicate that PFGE and AFLP are equally discriminative and could in this setting be used for typing purposes over the whole 5-year period.     

An efficient multivariate approach for estimating preference when individual observations are dependent

1. We discuss aspects of resource selection based on observing a given vector of resource variables for different individuals at discrete time steps. A new technique for estimating preference of habitat characteristics, applicable when there are multiple individual observations, is proposed. 2. We first show how to estimate preference on the population and individual level when only a single site- or resource component is observed. A variance component model based on normal scores in used to estimate mean preference for the population as well as the heterogeneity among individuals defined by the intra-class correlation. 3. Next, a general technique is proposed for time series of observations of a vector with several components, correcting for the effect of correlations between these. The preference of each single component is analyzed under the assumption of arbitrarily complex selection of the other components. This approach is based on the theory for conditional distributions in the multi-normal model. 4. The method is demonstrated using a data set of radio-tagged dispersing juvenile goshawks and their site characteristics, and can be used as a general tool in resource or habitat selection analysis.     

Assessment of species diversity from species abundance distributions at different localities

We show how the spatial structure of species diversity can be analyzed using the correlation between the log abundances of the species in the communities, assuming that two communities at different localities can be described by a bivariate lognormal species abundance distribution. A useful property of this approach is that the log abundances of the species at two localities can be considered as samples from a bivariate normal distribution defined by only five parameters. The variances and the correlation can be estimated by maximum likelihood methods even if there is no information about the sampling intensity and the number of unobserved species. This method also enables estimation of over-dispersion in the sampling relative to a Poisson distribution that allows sampling adjustment of the estimate of β-diversity. Furthermore, we also obtain a partitioning of species diversity into additive components of α-, β- and γ-diversity. For instance, if the correlation between the log abundances of the species is close to one, the same species will be common and rare in the two communities and the β-diversity will be low. We illustrate this approach by analysing similarities of communities of rare and endangered species of oak-living beetles in south-eastern Norway. The number of recorded species was estimated to be only 48.1% of the total number of species actually present in these communities. The correlations among communities dropped rather quickly with distance with a scaling of order 200 km. This illustrates large spatial heterogeneity in species composition, which should be accounted for in the design of schemes of such devices for assessing species diversity in these habitat-types.     

First observations of temperature tolerances of adult male snow crab (Chionoecetes opilio) from the Barents Sea population and the effects on the fisheries strategy

This study investigates the effects of temperature on the survival, food intake, oxygen consumption and growth during long-term live holding of captive male snow crab (Chionoecetes opilio) (average?=?0.7?kg). The crabs were held at three different temperatures, 3, 6 and 9°C. The trials were done using groups of snow crabs held in nine land-based holding tanks (three replicates per temperature treatment). The results showed that temperature had a significant effect on survival. The survival rate at 3°C (61%) was significantly higher than at 6°C (33%) and at 9°C (28%). Specific oxygen consumption rates of unfed crab at 6°C were significantly higher than at 9°C and 3°C. In summary, the current study shows that the Barents Sea snow crab have a narrow temperature range in which they thrive compared with the Barents Sea red king crab (Paralithodes camtschaticus). Barents Sea snow crab has similar metabolic and physiological attributes to other major snow crab populations. In conditions when ambient temperatures are approximately 6°C, it may prove beneficial for animal welfare and also be financially advantageous to reduce ambient water temperatures in live snow crab holding facilities on boat or on land.     

Modelling time to population extinction when individual reproduction is autocorrelated

In nature, individual reproductive success is seldom independent from year to year, due to factors such as reproductive costs and individual heterogeneity. However, population projection models that incorporate temporal autocorrelations in individual reproduction can be difficult to parameterise, particularly when data are sparse. We therefore examine whether such models are necessary to avoid biased estimates of stochastic population growth and extinction risk, by comparing output from a matrix population model that incorporates reproductive autocorrelations to output from a standard age‐structured matrix model that does not. We use a range of parameterisations, including a case study using moose data, treating probabilities of switching reproductive class as either fixed or fluctuating. Expected time to extinction from the two models is found to differ by only small amounts (under 10%) for most parameterisations, indicating that explicitly accounting for individual reproductive autocorrelations is in most cases not necessary to avoid bias in extinction estimates.     

Sequence Characterization of a Unique Intergenic Spacer in Gadiformes Mitochondrial DNA

The nucleotide sequences of intergenic spacers located between the tRNA^Thr and tRNA^Pro genes in mitochondrial DNA of cod fishes (order Godiformes) were determined. Spacers from eight species representing two families of cod fishes were analyzed and found to vary in size from 25 to 99 bp. Each spacer sequence contains one or two copies of a conserved 17-bp motif. Four to five central nucleotides of this motif constitute a substitutional hot spot as observed from interspecific and intraspecific comparisons. The substitution rate of the spacer is approximately twice that of the variable part I of the mitochondrial DNA control region, making this sequence region interesting as a molecular marker in population studies or stock assessments of cod fishes. We propose that the spacer originated in a duplication event and evolved into a functional domain, perhaps by binding regulatory proteins. Accepted February 26, 1999     

Trace Element Profiles in Single Strands of Human Hair Determined by HR-ICP-MS

Trace element analysis of human hair has the potential to reveal retrospective information about an individual's nutritional status and exposure. As trace elements are incorporated into the hair during the growth process, longitudinal segments of the hair may reflect the body burden during the growth period. We have evaluated the potential of human hair to indicate exposure or nutritional status over time by analysing trace element profiles in single strands of human hair. The hair strands from five healthy and occupationally unexposed subjects were cut into 1-cm long segments starting from the scalp. By using high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS), we achieved profiles of 12 elements in single strands of human hair, namely, Ag, As, Au, Cd, Cu, Hg, Fe, Pb, Se, Sr, U and Zn. We have shown that trace element analysis along single strands of human hair can yield information about essential and toxic elements, and for some elements, can be correlated with seasonal changes in diet and exposure. The information obtained from the trace element profiles of human hair in this study substantiates the potential of hair as a biomarker.     

Estimating the growth of a newly established moose population using reproductive value

Estimating the population growth rate and environmental stochasticity of long-lived species is difficult because annual variation in population size is influenced by temporal autocorrelations caused by fluctuations in the age-structure. Here we use the dynamics of the reproductive value to estimate the long-term growth rate s and the environmental variance of a moose population that recently colonized the island of Vega in northern Norway. We show that the population growth rate was high (ŝ=0.26). The major stochastic influences on the population dynamics were due to demographic stochasticity, whereas the environmental variance was not significantly different from 0. This supports the suggestion that population growth rates of polytocous ungulates are high, and that demographic stochasticity must be assessed when estimating the growth of small ungulate populations.     

Synthetic and spectroscopic studies of 2-C-methyl-erythritol and 2-C-methyl-threito

The synthesis of 2-C-methyl-d,l-threitol and two isopropylidene derivatives of 2-C-methyl-d-erythritol is described. ¹H and ¹³C NMR spectra of these and several related compounds are discussed.