Phenotypic and genotypic characterization of Klebsiella pneumoniae isolates recovered from nonhuman primates

Klebsiella pneumoniae is a zoonotic, Gram-negative member of the family Enterobacteriaceae and is the causative agent of nosocomial septicemic, pneumonic, and urinary tract infections. Recently, pathogenic strains of K. pneumoniae sharing a hypermucoviscosity (HMV) phenotype have been attributed to multisystemic abscessation in both human and nonhuman primates. Although K. pneumoniae is a well-recognized zoonotic agent, there is a lack of general information including adequate diagnostic methods or treatments for nonhuman primates. In an effort to increase the body of knowledge of this enigmatic pathogen, K. pneumoniae isolates from African green monkeys (Chlorocebus aethiops sabaeus) on the island of St. Kitts, West Indies were genotypically and phenotypically characterized. Genetic fingerprints generated by PCR-mediated genomic fingerprinting, phenotypic characterization, and antimicrobial susceptibility all identified a high degree of similarity between the HMV and non-HMV K. pneumoniae isolates. The results obtained from this work will help establish a baseline for the development of efficacious diagnostic methods and treatment strategies for both human and nonhuman primates.     

Evaluation of the Growth Assessment Protocol (GAP) for antenatal detection of small for gestational age: The DESiGN cluster randomised trial

BackgroundAntenatal detection and management of small for gestational age (SGA) is a strategy to reduce stillbirth. Large observational studies provide conflicting results on the effect of the Growth Assessment Protocol (GAP) in relation to detection of SGA and reduction of stillbirth; to the best of our knowledge, there are no reported randomised control trials. Our aim was to determine if GAP improves antenatal detection of SGA compared to standard care.Methods and findingsThis was a pragmatic, superiority, 2-arm, parallel group, open, cluster randomised control trial. Maternity units in England were eligible to participate in the study, except if they had already implemented GAP. All women who gave birth in participating clusters (maternity units) during the year prior to randomisation and during the trial (November 2016 to February 2019) were included. Multiple pregnancies, fetal abnormalities or births before 24⁺¹ weeks were excluded. Clusters were randomised to immediate implementation of GAP, an antenatal care package aimed at improving detection of SGA as a means to reduce the rate of stillbirth, or to standard care. Randomisation by random permutation was stratified by time of study inclusion and cluster size. Data were obtained from hospital electronic records for 12 months prerandomisation, the washout period (interval between randomisation and data collection of outcomes), and the outcome period (last 6 months of the study). The primary outcome was ultrasound detection of SGA (estimated fetal weight <10th centile using customised centiles (intervention) or Hadlock centiles (standard care)) confirmed at birth (birthweight <10th centile by both customised and population centiles). Secondary outcomes were maternal and neonatal outcomes, including induction of labour, gestational age at delivery, mode of birth, neonatal morbidity, and stillbirth/perinatal mortality. A 2-stage cluster–summary statistical approach calculated the absolute difference (intervention minus standard care arm) adjusted using the prerandomisation estimate, maternal age, ethnicity, parity, and randomisation strata. Intervention arm clusters that made no attempt to implement GAP were excluded in modified intention to treat (mITT) analysis; full ITT was also reported. Process evaluation assessed implementation fidelity, reach, dose, acceptability, and feasibility. Seven clusters were randomised to GAP and 6 to standard care. Following exclusions, there were 11,096 births exposed to the intervention (5 clusters) and 13,810 exposed to standard care (6 clusters) during the outcome period (mITT analysis). Age, height, and weight were broadly similar between arms, but there were fewer women: of white ethnicity (56.2% versus 62.7%), and in the least deprived quintile of the Index of Multiple Deprivation (7.5% versus 16.5%) in the intervention arm during the outcome period. Antenatal detection of SGA was 25.9% in the intervention and 27.7% in the standard care arm (adjusted difference 2.2%, 95% confidence interval (CI) −6.4% to 10.7%; p = 0.62). Findings were consistent in full ITT analysis. Fidelity and dose of GAP implementation were variable, while a high proportion (88.7%) of women were reached. Use of routinely collected data is both a strength (cost-efficient) and a limitation (occurrence of missing data); the modest number of clusters limits our ability to study small effect sizes.ConclusionsIn this study, we observed no effect of GAP on antenatal detection of SGA compared to standard care. Given variable implementation observed, future studies should incorporate standardised implementation outcomes such as those reported here to determine generalisability of our findings.Trial registrationThis trial is registered with the ISRCTN registry, ISRCTN67698474.

Matias C Vieira and colleagues evaluate the Growth Assessment Protocol (GAP) for antenatal detection of small for gestational age in the DESiGN cluster randomised trial.     

Divergent effects of peripheral and global neuropeptide Y deletion

Objectives:Neuropeptide Y (NPY) is involved in the coordination of bone mass and adiposity. However, multiple NPY sources exist and their individual contribution to the skeleton and adiposity not known. The objectives of our study were to evaluate the effects of peripheral mesenchymal derived NPY to the skeleton and adiposity and to compare them to the global NPY^KO model.Methods:To study the role of mesenchymal-derived NPY, we crossed conditional NPY (NPY^fl/fl) mice with Prx1cre to generate PrxNPY^KO mice. The bone phenotype was assessed using micro-CT. The skeletal phenotype of PrxNPY^KO mice was subsequently compared to global NPY^KO model. We evaluated body weight, adiposity and functionally assessed the feeding response of NPY neurons to determine whether central NPY signaling was altered by Prx1cre.Results:We identified the increase in cortical parameters in PrxNPY^KO mice with no changes to cancellous bone. This was the opposite phenotype to global NPY^KO mice generated from the same conditional allele. Male NPY^KO mice have increased adiposity, while PrxNPY^KO mice showed no difference, demonstrating that local mesenchymal-derived NPY does not influence adiposity.Conclusion:NPY mediates both positive and negative effects on bone mass via separate regulatory pathways. Deletion of mesenchymal-derived NPY had a positive effect on bone mass.     

Insular avian adaptations on two Neotropical continental islands

Aim Most studies of avian insular adaptations have focused on oceanic islands, which may not allow characters that are insular adaptations to be teased apart from those that benefit dispersal and colonization. Using birds on continental islands, we investigated characters that evolved in situ in response to insular environments created by late Pleistocene sea level rise. Location Trinidad and Tobago and continental South America. Methods We weighed fresh flight muscles and measured museum skeletal specimens of seven species of birds common to the continental islands of Trinidad and Tobago. Results When corrected for body size, study species exhibited significantly smaller flight muscles, sterna and sternal keels on Tobago than on larger Trinidad and continental South America. Tobago populations were more ‘insular’ in their morphologies than conspecifics on Trinidad or the continent in other ways as well, including having longer bills, longer wings, longer tails and longer legs. Main conclusions We hypothesize that the longer bills enhance foraging diversity, the longer wings and tails compensate for the smaller pectoral assemblage (allowing for retention of volancy, but with a probable reduction in flight power and speed), and the longer legs expand perching ability. Each of these differences is likely to be related to the lower diversity and fewer potential predators and competitors on Tobago compared with Trinidad. These patterns of smaller flight muscles and larger bills, legs, wings and tails in island birds are not the results of selection for island dispersal and colonization, but probably arose from selection pressures acting on populations already inhabiting these islands.     

Heteroaryl urea inhibitors of fatty acid amide hydrolase: Structure–mutagenicity relationships for arylamine metabolites

The structure–activity relationships for a series of heteroaryl urea inhibitors of fatty acid amide hydrolase (FAAH) are described. Members of this class of inhibitors have been shown to inactivate FAAH by covalent modification of an active site serine with subsequent release of an aromatic amine from the urea electrophile. Systematic Ames II testing guided the optimization of urea substituents by defining the structure–mutagenicity relationships for the released aromatic amine metabolites. Potent FAAH inhibitors were identified having heteroaryl amine leaving groups that were non-mutagenic in the Ames II assay.     

New developments in the behavioral ecology and conservation of ruffed lemurs (Varecia)

The papers in this issue were presented at a symposium during the 25th Annual Meeting of the American Society of Primatologists held in Oklahoma City, Oklahoma, in June 2002. This symposium brought together many of the scientists who have contributed to our knowledge of ruffed lemur ecology, behavior, and conservation in the past decade. One objective was to share and compare key findings about ruffed lemurs (Varecia) resulting from long-term field studies at various sites in Madagascar. A second objective was to cross-fertilize work being done in the wild with that being done in captivity, with the aim of advancing a common conservation mission for this critically endangered genus. Varecia is a prime candidate for synthetic assessments such as these because it has now been studied in both the northern and southern reaches of its geographic range, and has also been the focus of a captive-to-wild reinforcement project. The papers in this issue contribute to 1) the establishment of reference ranges for a suite of physiological parameters in healthy wild Varecia populations; 2) environmental enrichment aimed at preserving species-typical behaviors in captivity; 3) an understanding of how forest structure, floristic composition, and fruiting phenology in areas with differing disturbance histories correlate with the natural occurrence and abundance of Varecia; 4) primary knowledge concerning dominance relations between the sexes and group leadership in wild Varecia; and 5) primary knowledge concerning how wild Varecia, with their unusual reproductive pattern and heavy reliance on fruit, modulate their activity budgets seasonally and in tandem with reproductive stages.     

Conformational changes in BID, a pro-apoptotic BCL-2 family member, upon membrane binding. A site-directed spin labeling study

The BCL-2 family proteins constitute a critical control point in apoptosis. BCL-2 family proteins display structural homology to channel-forming bacterial toxins, such as colicins, transmembrane domain of diphtheria toxin, and the N-terminal domain of delta-endotoxin. By analogy, it has been hypothesized the BCL-2 family proteins would unfold and insert into the lipid bilayer upon membrane association. We applied the site-directed spin labeling method of electron paramagnetic resonance spectroscopy to the pro-apoptotic member BID. Here we show that helices 6-8 maintain an alpha-helical conformation in membranes with a lipid composition resembling mitochondrial outer membrane contact sites. However, unlike colicins and the transmembrane domain of diphtheria toxin, these helices of BID are bound to the lipid bilayer without adopting a transmembrane orientation. Our study presents a more detailed model for the reorganization of the structure of tBID on membranes.