Assessment of trends in predation pressure on insects across temperate forest microhabitats

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Appraisal Tools for Clinical Practice Guidelines: A Systematic Review

Introduction

Clinical practice guidelines can improve healthcare processes and patient outcomes, but are often of low quality. Guideline appraisal tools aim to help potential guideline users in assessing guideline quality. We conducted a systematic review of publications describing guideline appraisal tools in order to identify and compare existing tools.

Methods

Among others we searched MEDLINE, EMBASE and the Cochrane Database of Systematic Reviews from 1995 to May 2011 for relevant primary and secondary publications. We also handsearched the reference lists of relevant publications.On the basis of the available literature we firstly generated 34 items to be used in the comparison of appraisal tools and grouped them into thirteen quality dimensions. We then extracted formal characteristics as well as questions and statements of the appraisal tools and assigned them to the items.

Results

We identified 40 different appraisal tools. They covered between three and thirteen of the thirteen possible quality dimensions and between three and 29 of the possible 34 items. The main focus of the appraisal tools were the quality dimensions “evaluation of evidence” (mentioned in 35 tools; 88%), “presentation of guideline content” (34 tools; 85%), “transferability” (33 tools; 83%), “independence” (32 tools; 80%), “scope” (30 tools; 75%), and “information retrieval” (29 tools; 73%). The quality dimensions “consideration of different perspectives” and “dissemination, implementation and evaluation of the guideline” were covered by only twenty (50%) and eighteen tools (45%) respectively.

Conclusions

Most guideline appraisal tools assess whether the literature search and the evaluation, synthesis and presentation of the evidence in guidelines follow the principles of evidence-based medicine. Although conflicts of interest and norms and values of guideline developers, as well as patient involvement, affect the trustworthiness of guidelines, they are currently insufficiently considered. Greater focus should be placed on these issues in the further development of guideline appraisal tools.     

A computational approach for inferring the cell wall properties that govern guard cell dynamics

Guard cells dynamically adjust their shape in order to regulate photosynthetic gas exchange, respiration rates and defend against pathogen entry. Cell shape changes are determined by the interplay of cell wall material properties and turgor pressure. To investigate this relationship between turgor pressure, cell wall properties and cell shape, we focused on kidney‐shaped stomata and developed a biomechanical model of a guard cell pair. Treating the cell wall as a composite of the pectin‐rich cell wall matrix embedded with cellulose microfibrils, we show that strong, circumferentially oriented fibres are critical for opening. We find that the opening dynamics are dictated by the mechanical stress response of the cell wall matrix, and as the turgor rises, the pectinaceous matrix stiffens. We validate these predictions with stomatal opening experiments in selected Arabidopsis cell wall mutants. Thus, using a computational framework that combines a 3D biomechanical model with parameter optimization, we demonstrate how to exploit subtle shape changes to infer cell wall material properties. Our findings reveal that proper stomatal dynamics are built on two key properties of the cell wall, namely anisotropy in the form of hoop reinforcement and strain stiffening.     

Hormone levels predict individual differences in reproductive success in a passerine bird

Hormones mediate major physiological and behavioural components of the reproductive phenotype of individuals. To understand basic evolutionary processes in the hormonal regulation of reproductive traits, we need to know whether, and during which reproductive phases, individual variation in hormone concentrations relates to fitness in natural populations. We related circulating concentrations of prolactin and corticosterone to parental behaviour and reproductive success during both the pre-breeding and the chick-rearing stages in both individuals of pairs of free-living house sparrows, Passer domesticus. Prolactin and baseline corticosterone concentrations in pre-breeding females, and prolactin concentrations in pre-breeding males, predicted total number of fledglings. When the strong effect of lay date on total fledgling number was corrected for, only pre-breeding baseline corticosterone, but not prolactin, was negatively correlated with the reproductive success of females. During the breeding season, nestling provisioning rates of both sexes were negatively correlated with stress-induced corticosterone levels. Lastly, individuals of both sexes with low baseline corticosterone before and high baseline corticosterone during breeding raised the most offspring, suggesting that either the plasticity of this trait contributes to reproductive success or that high parental effort leads to increased hormone concentrations. Thus hormone concentrations both before and during breeding, as well as their seasonal dynamics, predict reproductive success, suggesting that individual variation in absolute concentrations and in plasticity is functionally significant, and, if heritable, may be a target of selection.     

Synthesis and antimycobacterial properties of N-substituted 6-amino-5-cyanopyrazine-2-carboxamides

A series of fifteen new compounds related to pyrazinamide (PZA) were synthesized, characterized with analytical data and screened for antimycobacterial, antifungal and antibacterial activity. The series consists of 6-chloro-5-cyanopyrazine-2-carboxamide and N-substituted 6-amino-5-cyanopyrazine-2-carboxamides, derived from the previous by nucleophilic substitution with various non-aromatic amines (alkylamines, cycloalkylamines, heterocyclic amines). Some of the compounds exerted antimycobacterial activity against Mycobacterium tuberculosis equal to pyrazinamide (12.5-25 μg/mL). More importantly, 6-chloro-5-cyanopyrazine-2-carboxamide and 5-cyano-6-(heptylamino)pyrazine-2-carboxamide were active against Mycobacterium kansasii and Mycobacterium avium, which are unsusceptible to PZA. Basic structure-activity relationships are presented. Only weak antifungal and no antibacterial activity was detected.     

Canine antibody response to Phlebotomus perniciosus bites negatively correlates with the risk of Leishmania infantum transmission

Background

Phlebotomine sand flies are blood-sucking insects that can transmit Leishmania parasites. Hosts bitten by sand flies develop an immune response against sand fly salivary antigens. Specific anti-saliva IgG indicate the exposure to the vector and may also help to estimate the risk of Leishmania spp. transmission. In this study, we examined the canine antibody response against the saliva of Phlebotomus perniciosus, the main vector of Leishmania infantum in the Mediterranean Basin, and characterized salivary antigens of this sand fly species.

Methodology/Principal Findings

Sera of dogs bitten by P. perniciosus under experimental conditions and dogs naturally exposed to sand flies in a L. infantum focus were tested by ELISA for the presence of anti-P. perniciosus antibodies. Antibody levels positively correlated with the number of blood-fed P. perniciosus females. In naturally exposed dogs the increase of specific IgG, IgG1 and IgG2 was observed during sand fly season. Importantly, Leishmania-positive dogs revealed significantly lower anti-P. perniciosus IgG2 compared to Leishmania-negative ones. Major P. perniciosus antigens were identified by western blot and mass spectrometry as yellow proteins, apyrases and antigen 5-related proteins.

Conclusions

Results suggest that monitoring canine antibody response to sand fly saliva in endemic foci could estimate the risk of L. infantum transmission. It may also help to control canine leishmaniasis by evaluating the effectiveness of anti-vector campaigns. Data from the field study where dogs from the Italian focus of L. infantum were naturally exposed to P. perniciosus bites indicates that the levels of anti-P. perniciosus saliva IgG2 negatively correlate with the risk of Leishmania transmission. Thus, specific IgG2 response is suggested as a risk marker of L. infantum transmission for dogs.     

Experimentally Induced Repeated Anhydrobiosis in the Eutardigrade Richtersius coronifer

Tardigrades represent one of the main animal groups with anhydrobiotic capacity at any stage of their life cycle. The ability of tardigrades to survive repeated cycles of anhydrobiosis has rarely been studied but is of interest to understand the factors constraining anhydrobiotic survival. The main objective of this study was to investigate the patterns of survival of the eutardigrade Richtersius coronifer under repeated cycles of desiccation, and the potential effect of repeated desiccation on size, shape and number of storage cells. We also analyzed potential change in body size, gut content and frequency of mitotic storage cells. Specimens were kept under non-cultured conditions and desiccated under controlled relative humidity. After each desiccation cycle 10 specimens were selected for analysis of morphometric characteristics and mitosis. The study demonstrates that tardigrades may survive up to 6 repeated desiccations, with declining survival rates with increased number of desiccations. We found a significantly higher proportion of animals that were unable to contract properly into a tun stage during the desiccation process at the 5^th and 6^th desiccations. Also total number of storage cells declined at the 5^th and 6^th desiccations, while no effect on storage cell size was observed. The frequency of mitotic storage cells tended to decline with higher number of desiccation cycles. Our study shows that the number of consecutive cycles of anhydrobiosis that R. coronifer may undergo is limited, with increased inability for tun formation and energetic constraints as possible causal factors.     

Evaluation of different Bacillus strains in respect of their ability to produce Surfactin in a model fermentation process with integrated foam fractionation

Biosurfactants increasingly gain attention due to the manifold of possible applications and production on the basis of renewable resources. Owing to its various characteristics, Surfactin is one of the most studied biosurfactants. Since its discovery, several Surfactin producers have been identified, but their capacity to produce Surfactin has not been evaluated in a comparison. Six different Bacillus strains were analyzed regarding their ability to produce Surfactin in model fermentations with integrated foam fractionation, for in situ product enrichment and removal. Three of the investigated strains are commonly used in Surfactin production (ATCC 21332, DSM 3256, DSM 3258), whereas two Bacillus strains are described for the first time (DSM 1090, LM43a50°C) as Surfactin producers. Additionally, the Bacillus subtilis type strain DSM 10^T was included in the evaluation. Interestingly, all strains, except DSM 3256, featured high values for Surfactin recovered from foam in comparison to other studies, ranging between 0.4 and 1.05 g. The fermentation process was characterized by calculating procedural parameters like substrate yield Y _X/S, product yield Y _P/X, specific growth rate μ, specific productivity q _Surfactin, volumetric productivity q _Surfactin, Surfactin and bacterial enrichment as well as Surfactin recovery. The strains differ most in specific and volumetric productivity; nevertheless, it is evident that it is not possible to name a Bacillus strain that is the most appropriate for the production of Surfactin under these conditions. In contrast, it becomes apparent that the choice of a specific strain should depend on the applied fermentation conditions.