High oviposition rate ofDasineura marginemtorquens onSalix viminalis genotypes unsuitable for offspring survival

A short history of contact betweenDasineura marginemtorquens and resistant genotypes ofSalix viminalis has previously been suggested as an explanation for a poor correspondence between female oviposition preference and larval performance on certain host types. The discovery of resistant wild willows instigated a quest for an alternative hypothesis. This study presents data from laboratory and field experiments that were designed to detect variability in host preferences of individual members of the midge population. Field tests showed that the oviposition site choices of females followed the same random-natured pattern as choices of females in laboratory situations. Ovipositing females did not distinguish between willow genotypes with very high or very low larval mortality. No differences in post-alighting behavior of midges on the two willow types were discovered. Observations revealed that females usually remained and oviposited on the first plant with which they came into contact, regardless of genotype.     

Aspects of statin prescribing in Norwegian counties with high,average and low statin consumption – an individual-level prescription database study

Background  

A previous study has shown that variations in threshold and intensity (lipid goal attainment) of statins for primary prevention contribute to regional differences in overall consumption of statins in Norway. Our objective was to explore how differences in prevalences of use, dosing characteristics, choice of statin and continuity of therapy in individual patients adds new information to previous results.     

Performing Isometric Force Control in Combination with a Cognitive Task: A Multidimensional Assessment

Introduction

We used a multidimensional approach to study isometric force control in single and dual-task conditions.

Methods

Multiple measures of performance, efficiency, variability, and structural interference were calculated at low and higher force levels under single (force maintenance) and dual-task (force maintenance and reaction time) conditions.

Results

Reaction time and signal-to-noise ratio were larger in the dual-task conditions. They were also greater for the higher force condition, while sample entropy was lower. Perturbation analyses revealed smaller relative amplitude of downward perturbations for the higher force level.

Discussion

Attentional effort and efficiency are positively related when force level increases, and inversely related to entropy. These relations were presumably mediated by attentional investment. Behavioral perturbations show that attentional resources and structural interference models are not mutually exclusive to account for dual-task situation. Overall, the present study highlights the interest of a multidimensional assessment of force control.     

Association of P2Y2 receptor SNPs with bone mineral density and osteoporosis risk in a cohort of Dutch fracture patients

The P2Y₂ receptor is a G-protein-coupled receptor with adenosine 5′-triphosphate (and UTP) as natural ligands. It is thought to be involved in bone physiology in an anti-osteogenic manner. As several non-synonymous single nucleotide polymorphisms (SNPs) have been identified within the P2Y₂ receptor gene in humans, we examined associations between genetic variations in the P2Y₂ receptor gene and bone mineral density (BMD) (i.e., osteoporosis risk), in a cohort of fracture patients. Six hundred and ninety women and 231 men aged ≥50 years, visiting an osteoporosis outpatient clinic at Maastricht University Medical Centre for standard medical follow-up after a recent fracture, were genotyped for three non-synonymous P2Y₂ receptor gene SNPs. BMD was measured at three locations (total hip, lumbar spine, and femoral neck) using dual-energy X-ray absorptiometry. Differences in BMD between different genotypes were tested using analysis of covariance. In women, BMD values at all sites were significantly different between the genotypes for the Leu46Pro polymorphism, with women homozygous for the variant allele showing the highest BMD values (0.05 > p > 0.01). The Arg312Ser and Arg334Cys polymorphisms showed no differences in BMD values between the different genotypes. This is the first report that describes the association between the Leu46Pro polymorphism of the human P2Y₂ receptor and the risk of osteoporosis.     

Computer Graphics Modelling and Molecular Dynamics Simulation of the Core of the Self Splicing Intervening Sequence of the T4 NrdB mRNA in the Presence of the Guanosine Cofactor

Abstract

The active site of the self splicing intron in the T4 nrdB RNA has been modelled on a graphics workstation on the basis of the suggested 3D arrangement of the Tetrahymena IVS¹. This structure was then subjected to energy minimization and molecular dynamics simulation to relax tensions. The cofactor guanosine was docked to a proposed² binding site where it was found to fit well.     

Nutrients and water availability constrain the seasonality of vegetation activity in a Mediterranean ecosystem

Anthropogenic nitrogen (N) deposition and resulting differences in ecosystem N and phosphorus (P) ratios are expected to impact photosynthetic capacity, that is, maximum gross primary productivity (GPP_max). However, the interplay between N and P availability with other critical resources on seasonal dynamics of ecosystem productivity remains largely unknown. In a Mediterranean tree–grass ecosystem, we established three landscape‐level (24 ha) nutrient addition treatments: N addition (NT), N and P addition (NPT), and a control site (CT). We analyzed the response of ecosystem to altered nutrient stoichiometry using eddy covariance fluxes measurements, satellite observations, and digital repeat photography. A set of metrics, including phenological transition dates (PTDs; timing of green‐up and dry‐down), slopes during green‐up and dry‐down period, and seasonal amplitude, were extracted from time series of GPP_max and used to represent the seasonality of vegetation activity. The seasonal amplitude of GPP_max was higher for NT and NPT than CT, which was attributed to changes in structure and physiology induced by fertilization. PTDs were mainly driven by rainfall and exhibited no significant differences among treatments during the green‐up period. Yet, both fertilized sites senesced earlier during the dry‐down period (17–19 days), which was more pronounced in the NT due to larger evapotranspiration and water usage. Fertilization also resulted in a faster increase in GPP_max during the green‐up period and a sharper decline in GPP_max during the dry‐down period, with less prominent decline response in NPT. Overall, we demonstrated seasonality of vegetation activity was altered after fertilization and the importance of nutrient–water interaction in such water‐limited ecosystems. With the projected warming‐drying trend, the positive effects of N fertilization induced by N deposition on GPP_max may be counteracted by an earlier and faster dry‐down in particular in areas where the N:P ratio increases, with potential impact on the carbon cycle of water‐limited ecosystems.     

Community perceptions and treatment-seeking behaviour regarding reproductive tract infections including sexually transmitted infections in Lao PDR: a qualitative study

Creating community awareness of reproductive tract infections (RTI), including sexually transmitted infections (STI), and how to prevent them is essential to minimize their spread. Data on people's views about RTI/STI are entirely lacking in Laos. The aim of this study was thus to explore people's perceptions, treatment-seeking behaviour and understanding of information about RTI/STI, in urban and rural communities in two provinces in Laos. Fourteen focus group discussions and 20 in-depth interviews were held with 76 women and 56 men, selected purposively to provide diversity of socio-demographic backgrounds. Qualitative content analysis was employed for the data analysis. The major finding was that both male and female participants had a variety of misconceptions about the causes and symptoms of RTI/STI and their cure, and a reluctance to seek health care, which could cause delay in appropriate diagnosis and treatment. The most common treatment-seeking behaviour was self-medication through private pharmacies, following advice mostly given by friends and drug sellers. The main reasons for not going to health facilities were fear of social discrimination or shyness of genital examination. Complaints were also made about clinicians' negative attitudes towards 'dirty disease'. Although condom use was mentioned as a way to prevent RTI/STI, an unwillingness to use condoms was commonly expressed. The main media sources of RTI/STI information were radio and television, and access to health information was more difficult in rural areas. The health messages provided were mostly understood, except for some technical terms. The findings indicate that strengthening health education and promotion through interventions at the community level is recommended to improve quality of RTI/STI management. Health education messages should be more accessible in rural areas. There is also an urgent need to improve communication between RTI/STI patients and clinicians.     

Phylogenetic and metabolic diversity of Planctomycetes from anaerobic, sulfide- and sulfur-rich Zodletone Spring, Oklahoma

We investigated the phylogenetic diversity and metabolic capabilities of members of the phylum Planctomycetes in the anaerobic, sulfide-saturated sediments of a mesophilic spring (Zodletone Spring) in southwestern Oklahoma. Culture-independent analyses of 16S rRNA gene sequences generated using Planctomycetes-biased primer pairs suggested that an extremely diverse community of Planctomycetes is present at the spring. Although sequences that are phylogenetically affiliated with cultured heterotrophic Planctomycetes were identified, the majority of the sequences belonged to several globally distributed, as-yet-uncultured Planctomycetes lineages. Using complex organic media (aqueous extracts of the spring sediments and rumen fluid), we isolated two novel strains that belonged to the Pirellula-Rhodopirellula-Blastopirellula clade within the Planctomycetes. The two strains had identical 16S rRNA gene sequences, and their closest relatives were isolates from Kiel Fjord (Germany), Keauhou Beach (HI), a marine aquarium, and tissues of marine organisms (Aplysina sp. sponges and postlarvae of the giant tiger prawn Penaeus monodon). The closest recognized cultured relative of strain Zi62 was Blastopirellula marina (93.9% sequence similarity). Detailed characterization of strain Zi62 revealed its ability to reduce elemental sulfur to sulfide under anaerobic conditions, as well as its ability to produce acids from sugars; both characteristics may potentially allow strain Zi62 to survive and grow in the anaerobic, sulfide- and sulfur-rich environment at the spring source. Overall, this work indicates that anaerobic metabolic abilities are widely distributed among all major Planctomycetes lineages and suggests carbohydrate fermentation and sulfur reduction as possible mechanisms employed by heterotrophic Planctomycetes for growth and survival under anaerobic conditions.     

Group II intron in Bacillus cereus has an unusual 3' extension and splices 56 nucleotides downstream of the predicted site

All group II introns known to date fold into six functional domains. However, we recently identified an intron in Bacillus cereus ATCC 10987, B.c.I4, that splices 56nt downstream of the expected 3′ splice site in vivo (Tourasse et al. 2005, J. Bacteriol., 187, 5437–5451). In this study, we confirmed by ribonuclease protection assay that the 56-bp segment is part of the intron RNA molecule, and computational prediction suggests that it might form a stable stem-loop structure downstream of domain VI. The splicing of B.c.I4 was further investigated both in vivo and in vitro. Lariat formation proceeded primarily by branching at the ordinary bulged adenosine in domain VI without affecting the fidelity of splicing. In addition, the splicing efficiency of the wild-type intron was better than that of a mutant construct deleted of the 56-bp 3′ extension. These results indicate that the intron has apparently adapted to the extra segment, possibly through conformational adjustments. The extraordinary group II intron B.c.I4 harboring an unprecedented extra 3′ segment constitutes a dramatic example of the flexibility and adaptability of group II introns.