Quantifying non‐breeding season occupancy patterns and the timing and drivers of autumn migration for a migratory songbird using Doppler radar

For seasonal migrants, non‐breeding regions can play different roles in the ecology of their annual cycles: as stopover habitat, overwintering habitat, or as a combination in which some individuals stop‐over and others over‐winter. Such functional variations can lead to variation in occupancy dynamics and migration phenology to these different regions. In this study, we used data from archived Doppler weather surveillance radar to compare site‐occupancy and movement dynamics of a migratory songbird (tree swallow Tachycineta bicolor) between two non‐breeding areas: southeastern Louisiana and central peninsular Florida, USA. Specifically, in each area, we 1) quantified long‐term (1996–2012) non‐breeding season occupancy dynamics, 2) quantified variation in timing of autumn migration, and 3) tested which climate variables along their respective flyways were best correlated with variation in dates of arrival. Additionally, we cross‐validated the dynamics from archived radar with data from eBird, a large‐scale citizen science database that provides an independent measure of avian occupancy. We found strong and significant correlations between radar‐estimated and eBird‐estimated occupancy dynamics in both Louisiana and Florida. Long‐term Louisiana occupancy dynamics conformed to our hypothesis that this region acts as a combined stopover and overwintering region whereas Florida occupancy dynamics were akin to a traditional winter region. Arrival to Louisiana during the study period was much earlier and took place over a much shorter arrival window than did arrival to Florida, which showed much more gradual arrival over the course of several months. At both sites, annual variation in mean arrival date was best explained by the amount of precipitation along the lower portions of their respective migration flyways.     

Tissue expression profile of human neonatal Fc receptor (FcRn) in Tg32 transgenic mice

The neonatal Fc receptor (FcRn) is a homeostatic receptor responsible for prolonging immunoglobulin G (IgG) half-life by protecting it from lysosomal degradation and recycling it to systemic circulation. Tissue-specific FcRn expression is a critical parameter in physiologically-based pharmacokinetic (PBPK) modeling for translational pharmacokinetics of Fc-containing biotherapeutics. Using online peptide immuno-affinity chromatography coupled with high resolution mass spectrometry, we established a quantitative FcRn tissue protein expression profile in human FcRn (hFcRn) transgenic mice, Tg32 homozygous and hemizygous strains. The concentration of hFcRn across 14 tissues ranged from 3.5 to 111.2 pmole per gram of tissue. Our hFcRn quantification data from Tg32 mice will enable a more refined PBPK model to improve the accuracy of human PK predictions for Fc-containing biotherapeutics.     

Mechanism of Lithium Metal Penetration through Inorganic Solid Electrolytes

Li deposition is observed and measured on a solid electrolyte in the vicinity of a metallic current collector. Four types of ion‐conducting, inorganic solid electrolytes are tested: Amorphous 70/30 mol% Li₂S‐P₂S₅, polycrystalline β‐Li₃PS₄, and polycrystalline and single‐crystalline Li₆La₃ZrTaO₁₂ garnet. The nature of lithium plating depends on the proximity of the current collector to defects such as surface cracks and on the current density. Lithium plating penetrates/infiltrates at defects, but only above a critical current density. Eventually, infiltration results in a short circuit between the current collector and the Li‐source (anode). These results do not depend on the electrolytes shear modulus and are thus not consistent with the Monroe–Newman model for “dendrites.” The observations suggest that Li‐plating in pre‐existing flaws produces crack‐tip stresses which drive crack propagation, and an electrochemomechanical model of plating‐induced Li infiltration is proposed. Lithium short‐circuits through solid electrolytes occurs through a fundamentally different process than through liquid electrolytes. The onset of Li infiltration depends on solid‐state electrolyte surface morphology, in particular the defect size and density.     

Specific Strains of Escherichia coli Are Pathogenic for the Endometrium of Cattle and Cause Pelvic Inflammatory Disease in Cattle and Mice

Background

Escherichia coli are widespread in the environment and pathogenic strains cause diseases of mucosal surfaces including the female genital tract. Pelvic inflammatory disease (PID; metritis) or endometritis affects ∼40% of cattle after parturition. We tested the expectation that multiple genetically diverse E. coli from the environment opportunistically contaminate the uterine lumen after parturition to establish PID.

Methodology/Principal Findings

Distinct clonal groups of E. coli were identified by Random Amplification of Polymorphic DNA (RAPD) and Multilocus sequence typing (MLST) from animals with uterine disease and these differed from known diarrhoeic or extra-intestinal pathogenic E. coli. The endometrial pathogenic E. coli (EnPEC) were more adherent and invasive for endometrial epithelial and stromal cells, compared with E. coli isolated from the uterus of clinically unaffected animals. The endometrial epithelial and stromal cells produced more prostaglandin E₂ and interleukin-8 in response to lipopolysaccharide (LPS) purified from EnPEC compared with non-pathogenic E. coli. The EnPEC or their LPS also caused PID when infused into the uterus of mice with accumulation of neutrophils and macrophages in the endometrium. Infusion of EnPEC was only associated with bacterial invasion of the endometrium and myometrium. Despite their ability to invade cultured cells, elicit host cell responses and establish PID, EnPEC lacked sixteen genes commonly associated with adhesion and invasion by enteric or extraintestinal pathogenic E. coli, though the ferric yersiniabactin uptake gene (fyuA) was present in PID-associated EnPEC. Endometrial epithelial or stromal cells from wild type but not Toll-like receptor 4 (TLR4) null mice secreted prostaglandin E₂ and chemokine (C-X-C motif) ligand 1 (CXCL1) in response to LPS from EnPEC, highlighting the key role of LPS in PID.

Conclusions/Significance

The implication arising from the discovery of EnPEC is that development of treatments or vaccines for PID should focus specifically on EnPEC and not other strains of E. coli.     

It takes two: Heritable male effects on reproductive timing but not clutch size in a wild bird population*

Within-population variation in the traits underpinning reproductive output has long been of central interest to biologists. Since they are strongly linked to lifetime reproductive success, these traits are expected to be subject to strong selection and, if heritable, to evolve. Despite the formation of durable pair bonds in many animal taxa, reproductive traits are often regarded as female-specific, and estimates of quantitative genetic variation seldom consider a potential role for heritable male effects. Yet reliable estimates of such social genetic effects are important since they influence the amount of heritable variation available to selection. Based on a 52-year study of a nestbox-breeding great tit (Parus major) population, we apply “extended” bivariate animal models in which the heritable effects of both sexes are modeled to assess the extent to which males contribute to heritable variation in seasonal reproductive timing (egg laying date) and clutch size, while accommodating the covariance between the two traits. Our analyses show that reproductive timing is a jointly expressed trait in this species, with (positively covarying) heritable variation for laydate being expressed in both members of a breeding pair, such that the total heritable variance is 50% larger than estimated by traditional models. This result was robust to explicit consideration of a potential male-biased environmental confound arising through sexually dimorphic dispersal. In contrast to laydate, males’ contribution to heritable variation in clutch size was limited. Our study thus highlights the contrasting extent of social determination for two major components of annual reproductive success, and emphasizes the need to consider the social context of what are often considered individual-level traits.     

Peak dynamic force in human gait

Studies were made of the forces generated at heel stroke in human gait using both force plates having a high resonant frequencies (capable of picking up high frequency components in the contact force) as well as a force transducer inserted into the heel of the shoe of the subjects. The output traces were analyzed for the existence of high frequency impulsive loads during a normal walking cycle. The effect of the complicance of the foot and floor was studied with the force transducers. The results showed that during normal human gait the lower limb is subjected to a high frequency impulsive load at heel strike. The severity of this impulse varied with the individual, the velocity and angle with which the limb aproached the ground and the compliance of the two materials coming in contact at heel strike. The magnitude of this peak force varied from 0.5 to 1.25 times body weight and its frequency components from 10 to 75 Hz.     

Characterization of binding of four monoclonal antibodies to the human ovarian adenocarcinoma cell line HEY

Four mouse monoclonal antibodies (mAb) (10B, IgG1; 8C, IgG2a; M2A, IgG2a; M2D, IgG2b) were characterized with respect to their binding to the ovarian adenocarcinoma cell line HEY, using displacement assays and Scatchard plot analyses. The four mAb reacted with different antigens on the surface of HEY cells, with affinity constants ranging from 1 X 10(9) to 3 X 10(9) M-1. The number of binding sites per cell for each antibody was approximately 2 X 10(4). mAb 8C and M2D remained associated with the cell surface following binding to their respective antigens, while mAb 10B was rapidly internalized, with 50% of the bound mAb being lost from the cell surface during 4 h of incubation at 37 degrees C. These different binding characteristics of the mAb may influence their ability to target radioactivity and cytotoxic drugs to HEY cells.     

Individual and Population-Level Impacts of an Emerging Poxvirus Disease in a Wild Population of Great Tits

Emerging infectious diseases of wildlife can have severe effects on host populations and constitute a pressing problem for biodiversity conservation. Paridae pox is an unusually severe form of avipoxvirus infection that has recently been identified as an emerging infectious disease particularly affecting an abundant songbird, the great tit (Parus major), in Great Britain. In this study, we study the invasion and establishment of Paridae pox in a long-term monitored population of wild great tits to (i) quantify the impact of this novel pathogen on host fitness and (ii) determine the potential threat it poses to population persistence. We show that Paridae pox significantly reduces the reproductive output of great tits by reducing the ability of parents to fledge young successfully and rear those young to independence. Our results also suggested that pathogen transmission from diseased parents to their offspring was possible, and that disease entails severe mortality costs for affected chicks. Application of multistate mark-recapture modelling showed that Paridae pox causes significant reductions to host survival, with particularly large effects observed for juvenile survival. Using an age-structured population model, we demonstrate that Paridae pox has the potential to reduce population growth rate, primarily through negative impacts on host survival rates. However, at currently observed prevalence, significant disease-induced population decline seems unlikely, although pox prevalence may be underestimated if capture probability of diseased individuals is low. Despite this, because pox-affected model populations exhibited lower average growth rates, this emerging infectious disease has the potential to reduce the resilience of populations to other environmental factors that reduce population size.     

Patellar cartilage deformation in vivo after static versus dynamic loading

The objective of this study was to test the hypothesis that static loading (squatting at a 90 degrees angle) and dynamic loading (30 deep knee bends) cause different extents and patterns of patellar cartilage deformation in vivo. The two activities were selected because they imply different types of joint loading and reflect a realistic and appropriate range of strenuous activity. Twelve healthy volunteers were examined and the volume and thickness of the patellar cartilage determined before and from 90 to 320s after loading, using a water excitation gradient echo MR sequence and a three-dimensional (3D) distance transformation algorithm. Following knee bends, we observed a residual reduction of the patellar cartilage volume (-5.9+/-2.1%; p<0.01) and of the maximal cartilage thickness (-2.8+/-2.6%), the maximal deformation occurring in the superior lateral and the medial patellar facet. Following squatting, the change of patellar cartilage volume was -4.7+/-1.6% (p<0.01) and that of the maximal cartilage thickness -4.9+/-1.4% (p<0.01), the maximal deformation being recorded in the central aspect of the lateral patellar facet. The volume changes were significantly lower after squatting than after knee bends (p<0.05), but the maximal thickness changes higher (p<0.05). The results obtained in this study can serve to validate computer models of joint load transfer, to guide experiments on the mechanical regulation of chondrocyte biosynthesis, and to estimate the magnitude of deformation to be encountered by tissue-engineered cartilage within its target environment.