Multiscale patterns of movement in fragmented landscapes and consequences on demography of the snail kite in Florida

1. Habitat loss and fragmentation are major factors affecting vertebrate populations. A major effect of these habitat alterations is that they reduce movement of organisms. Despite the accepted importance of movement in driving the dynamics of many natural populations, movement of vertebrates in fragmented landscapes have seldom been estimated with robust statistical methods. 2. We estimated movement probabilities of snail kites Rosthramus sociabilis within the remaining wetlands in Florida. Using both radio-telemetry and banding information, we used a multistate modelling approach to estimate transition probabilities at two temporal scales (month; year) and multiple spatial scales. We examined kite movement among wetlands altered by three different levels of fragmentation: among wetlands separated by small physical barriers (e.g. road); among wetlands separated by moderate amount of matrix (< 5 km); and among wetlands separated by extensive matrix areas (> 15 km). 3. Kites moved extensively among contiguous wetlands (movement probability 0.29 per month), but significantly less among isolated wetlands (movement probability 0.10 per month). 4. Kites showed high levels of annual site fidelity to most isolated wetlands (probability ranged from 0.72 to 0.95 per year). 5. We tested the effects of patch size and interpatch distance on movement. Our modelling indicated an effect of both distance and patch size on juveniles' movement (but not adult) when examining movements among fragments. 6. Only a small proportion of kites escaped a regional drought by moving to refugia (wetlands less affected by drought). Many individuals died after the drought. During drought adult survival dropped by 16% while juvenile survival dropped by 86% (possibly because juveniles were less likely to reach refugia). 7. We hypothesize that fragmentation may decrease kite's resistance to drought by restricting exploratory behaviour.     

Native high-density lipoprotein augments monocyte responses to lipopolysaccharide (LPS) by suppressing the inhibitory activity of LPS-binding protein

High-density lipoprotein (HDL) is an abundant plasma lipoprotein that is generally thought to be anti-inflammatory in both health and infectious disease. It binds and neutralizes the bioactivity of the potent bacterial lipids, LPS and lipoteichoic acid, that stimulate host innate immune responses. LPS-binding protein (LBP) plays an important role in augmenting leukocyte responses to LPS, whereas high concentrations of LBP, in the range of those found in plasma, can be inhibitory. We found that native HDL (nHDL) augmented human monocyte responses to LPS in the presence of inhibitory concentrations of LBP as measured by production of TNF and other cytokines. HDL did not stimulate cells in the absence of LPS, and it did not augment responses that were stimulated by IL-1beta or lipoteichoic acid. This activity of HDL was inhibited by trypsin treatment, suggesting that one or more protein constituents of HDL are required. In contrast to nHDL, low-density lipoprotein, and reconstituted HDL did not possess this activity. The total lipoprotein fraction of normal plasma had activity that was similar to that of nHDL, whereas lipoproteins from septic patients with reduced HDL levels had a reduced ability to augment responses to LPS; this activity was restored by adding normal HDL to the patient lipoproteins. Our results demonstrate a novel proinflammatory activity of HDL that may help maintain sensitive host responses to LPS by suppressing the inhibitory activity of LBP. Our findings also raise the possibility that the decline of HDL during sepsis may help control the response to LPS.     

Factors influencing movement probabilities of a nomadic food specialist: proximate foraging benefits or ultimate gains from exploration?

We examined the factors that influenced movement probabilities of snail kites ( Rostrhamus sociabilis ) in Florida, USA, based on birds with radio transmitters ( n =282) during a three-year period from April 1992 through April 1995. We focused on the hypotheses that increased movement probabilities were in response to low food availability or low water levels; the latter also implying low food availability for this species. An alternative hypothesis was that snail kites exhibit exploratory behavior, and corresponding increased movement probabilities, during periods of high food availability. Movement probabilities were not consistent with the hypotheses that low water levels or low food availability were the proximate cues to initiate movement from one wetland to another. Movement probabilities were higher during periods of relatively high food availability and were not associated with water levels; thus were consistent with the hypothesis that snail kites exhibited exploratory behavior during times of food abundance. However, we do not believe that our results are in conflict with previous reports of increased movement during extreme food scarcity; rather, that these hypotheses are not mutually exclusive and reflect different resource levels. During extreme drying events, food becomes virtually unavailable and birds must either move or die, but during times of food abundance there may be an advantage of exploratory behavior. Given that local drying events occur at frequencies of approximately every 5–10 yr in this environment, having explored wetlands throughout their range reduces the need for "blind" searching for suitable alternative habitats when such events do occur.     

Extraction and quantification of daunomycin and doxorubicin in tissues

The measurement of intracellular concentrations of the anti-cancer drug doxorubicin was performed by the application of a simple cell extraction technique combined with a rapid high-performance liquid chromatographic separation. Quantitation was done by fluorescence detection. The extraction procedure was non-degradative and the mean recovery of drug was 95%. A high drug extraction efficiency was confirmed with radiolabeled [³H]doxorubicin. The method is applicable to normal and neoplastic tissue.     

Immune responses to stress after stress management training in patients with rheumatoid arthritis

Introduction

Psychological stress may alter immune function by activating physiological stress pathways. Building on our previous study, in which we report that stress management training led to an altered self-reported and cortisol response to psychological stress in patients with rheumatoid arthritis (RA), we explored the effects of this stress management intervention on the immune response to a psychological stress task in patients with RA.

Methods

In this study, 74 patients with RA, who were randomly assigned to either a control group or a group that received short stress management training, performed the Trier Social Stress Test (TSST) 1 week after the intervention and at a 9-week follow-up. Stress-induced changes in levels of key cytokines involved in stress and inflammatory processes (for example, interleukin (IL)-6 and IL-8) were assessed.

Results

Basal and stress-induced cytokine levels were not significantly different in patients in the intervention and control groups one week after treatment, but stress-induced IL-8 levels were lower in patients in the intervention group than in the control group at the follow-up assessment.

Conclusions

In line with our previous findings of lower stress-induced cortisol levels at the follow-up of stress management intervention, this is the first study to show that relatively short stress management training might also alter stress-induced IL-8 levels in patients with RA. These results might help to determine the role of immunological mediators in stress and disease.

Trial registration

The Netherlands National Trial Register (NTR1193)     

Genome-wide association study using deregressed breeding values for cryptorchidism and scrotal/inguinal hernia in two pig lines

Background

Cryptorchidism and scrotal/inguinal hernia are the most frequent congenital defects in pigs. Identification of genomic regions that control these congenital defects is of great interest to breeding programs, both from an animal welfare point of view as well as for economic reasons. The aim of this genome-wide association study (GWAS) was to identify single nucleotide polymorphisms (SNPs) that are strongly associated with these congenital defects. Genotypes were available for 2570 Large White (LW) and 2272 Landrace (LR) pigs. Breeding values were estimated based on 1 359 765 purebred and crossbred male offspring, using a binary trait animal model. Estimated breeding values were deregressed (DEBV) and taken as the response variable in the GWAS.

Results

Heritability estimates were equal to 0.26 ± 0.02 for cryptorchidism and to 0.31 ± 0.01 for scrotal/inguinal hernia. Seven and 31 distinct QTL regions were associated with cryptorchidism in the LW and LR datasets, respectively. The top SNP per region explained between 0.96% and 1.10% and between 0.48% and 2.77% of the total variance of cryptorchidism incidence in the LW and LR populations, respectively. Five distinct QTL regions associated with scrotal/inguinal hernia were detected in both LW and LR datasets. The top SNP per region explained between 1.22% and 1.60% and between 1.15% and 1.46% of the total variance of scrotal/inguinal hernia incidence in the LW and LR populations, respectively. For each trait, we identified one overlapping region between the LW and LR datasets, i.e. a region on SSC8 (Sus scrofa chromosome) between 65 and 73 Mb for cryptorchidism and a region on SSC13 between 34 and 37 Mb for scrotal/inguinal hernia.

Conclusions

The use of DEBV in combination with a binary trait model was a powerful approach to detect regions associated with difficult traits such as cryptorchidism and scrotal/inguinal hernia that have a low incidence and for which affected animals are generally not available for genotyping. Several novel QTL regions were detected for cryptorchidism and scrotal/inguinal hernia, and for several previously known QTL regions, the confidence interval was narrowed down.

Electronic supplementary material

The online version of this article (doi:10.1186/s12711-015-0096-6) contains supplementary material, which is available to authorized users.