Habitat-mediated predation risk and decision making of small birds at forest edges

We studied the effect of four components of predation risk, namely predation pressure, spatial variation in woody cover, visibility, and flock size, on the behaviour of four species of the Parus guild (crested tit, P. cristatus , willow tit, P. montanus , coal tit, P. ater , and goldcrest, Regulus regulus ) at the edge of patches of mature boreal forest. Birds used the exposed side of the edge (matrix) mainly during periods with low levels of predation pressure by pygmy owls ( Glaucidium passerinum ). Some species avoided edges under low light conditions. Birds in large groups were more prone to cross the edge, whereas group cohesion increased in risky situations, especially in the most vulnerable species (coal tit and goldcrest). The effects of these three components of predation risk were not general in that only some species responded to them, and in that intra-specific responses were not always consistent. In contrast, all behaviours examined in all four bird species (occurrence, matrix crossing, edge crossing, and group cohesion) appeared to be strongly affected by habitat-mediated predation risk. Mature boreal forests appeared to be qualitatively superior to any type of matrix in terms of protection against predators. Birds generally avoided open matrix, and seemed to move towards and across more developed stages in forest regeneration according to the ratio between food intake and predation risk attributable to a given matrix type. Open matrix (farmland and clearcuts) and very young plantations strongly restricted the rate of bird movement between old forest patches. Our results contrast with the widespread thought that birds have a great potential to use fragmented landscapes in a fine-grained manner. These limited movements across the landscape during winter might have important repercussions on the occupation of some forest patches by tits, their subsequent reproduction, and in turn their population dynamics.     

Growth hormone (GH)-independent stimulation of adiposity by GH secretagogues

Growth hormone secretagogues (GHSs) stimulate growth hormone (GH) secretion, which is lipolytic. Here we compared the effects of twice daily s.c. treatment of GH and the GHS, ipamorelin, on body fat in GH-deficient (lit/lit) and in GH-intact (+/lit and +/+) mice. In +/lit and lit/lit mice ipamorelin induced a small (15%) increase in body weight by 2 weeks, that was not further augmented by 9 weeks. GH treatment markedly enhanced body weight in both groups. Ipamorelin also increased fat pad weights relative to body weight in both lit/lit and +/lit mice. Two weeks GHS treatment (ipamorelin or GHRP-6) also increased relative body fat, quantified by in vivo dual energy X-ray absorpiometry (DEXA) in GH-intact mice. GH decreased relative fat mass in lit/lit mice and had no effect in GH-intact mice. Treatment with GHS, but not GH, increased serum leptin and food intake in GH-intact mice. Thus, GHSs increase body fat by GH-independent mechanisms that may include increased feeding.     

Baseline monitoring of codling moth (Lepidoptera: Tortricidae) larval response to benzoylhydrazine insecticides

A diet-incorporation larval bioassay was developed to measure the response of codling moth, Cydia pomonella (L.), to the benzoylhydrazine insecticides tebufenozide and methoxyfenozide. The bioassay tested neonates and third, fourth, and fifth instars from a laboratory colony and neonates and fourth instars from a pooled population collected from five certified-organic apple orchards. Bioassays were scored after 6 and 14 d. No differences between the laboratory and field population were found for either insecticide. Significant differences were found in the response of third and fifth instars between the 6 and 14 d bioassays, primarily due to a high proportion of moribund larvae in the shorter assay. Larval age had a significant effect in bioassays and was more pronounced in 6- versus 14-d tests. Fifth instars were significantly less susceptible to both insecticides than other stages, while responses of third and fourth instars were similar. The response of neonates was significantly different from third and fourth instars to tebufenozide but not with methoxyfenozide in the 14-d test. Field bioassays excluded the use of fifth instars and were scored after 14 d. LC50s estimated for 18 field-collected populations varied five- and ninefold for tebufenozide and methoxyfenozide, respectively. The responses of all but six field-collected populations were significantly different from the laboratory strain. Five of these six populations were collected from orchards with no history of organophosphate insecticide use. The LC50 for methoxyfenozide of one field-collected population reared in the laboratory for three generations declined fourfold, but was still significantly different from the laboratory population. These data suggest that transforming current codling moth management programs in Washington from a reliance on organophosphate insecticides to benzoylhydrazines may be difficult.     

Concentration-dependent effects of native and polymerised α1-antitrypsin on primary human monocytes, <Emphasis Type="Italic">in vitro</Emphasis>

Background  

α1-antitrypsin (AAT) is one of the major serine proteinase inhibitors controlling proteinases in many biological pathways. There is increasing evidence that AAT is able to exert other than antiproteolytic effects. To further examine this question we compared how various doses of the native (inhibitory) and the polymerised (non-inhibitory) molecular form of AAT affect pro-inflammatory responses in human monocytes, in vitro. Human monocytes isolated from different donors were exposed to the native or polymerised form of AAT at concentrations of 0.01, 0.02, 0.05, 0.1, 0.5 and 1 mg/ml for 18 h, and analysed to determine the release of cytokines and to detect the activity of NF-κB.     

Theobromine intoxication in a red fox and a European badger in Sweden

A red fox (Vulpes vulpes) and a European badger (Meles meles) were found dead on a golf-course in October 1997 near Stockholm (Sweden). At necropsy, both animals were obese and the main finding was acute circulatory collapse. Theobromine intoxication was suspected as chocolate waste was available at a nearby farm and no other cause of death could be detected. Gastric contents and samples of liver from both animals were analyzed by reversed-phase high pressure liquid chromatography for the presence of methylxanthines. Theobromine and caffeine were detected in gastric contents and theobromine was identified in the liver samples from both animals. This appears to be the first report of theobromine intoxication in the red fox and the European badger.     

Evaluation of red blood cell lysing solutions in the study of neutrophil oxidative burst by the DCFH assay

BACKGROUND: Neutrophil subpopulations with enhanced oxidative reactivity have been described in a number of clinical and in vitro settings. In the dichlorofluorescin (DCFH) oxidation assay, it is essential to maintain cellular viability and plasma membrane integrity through all stages of sample preparation. The process of erythrocyte lysing is crucial because a number of commercial lysing reagents can increase leukocyte membrane permeability. METHODS: We assessed viability [propidium iodide (PI) method], DCFH oxidation, and CD11b expression of resting or in vitro-stimulated neutrophils exposed to six different red cell lysing procedures. RESULTS: Formaldehyde-containing reagents (Optilyse B, FACS Lyse, and Erythrolyse) but not hypotonic shock or ammonium chloride (NH(4)Cl) solutions rendered 91.4--99.8% of resting neutrophils PI positive, with concomitant reductions in dichlorofluorescein (DCF) fluorescence, suggesting efflux of the fluorochrome. However, when stimulated with N-formyl-methionyl-leucyl-phenylalanine or Yersinia enterocolitica and then treated with FACS Lyse or Erythrolyse, up to 69.9% of neutrophils remained PI negative and exhibited enhanced DCF fluorescence. CD11b expression of PI-positive and -negative neutrophils was comparable, suggesting that they were activated equally. CONCLUSIONS: FACS Lyse and Erythrolyse can modify neutrophil plasma membrane integrity, whereas hypotonic shock and NH(4)Cl solutions retain cellular viability and are lysing methods of choice in evaluation of neutrophil respiratory burst by DCFH oxidation assay.     

Structure of the O-specific polysaccharide of Vibrio cholerae O9 containing 2-acetamido-2-deoxy-D-galacturonic acid

The O-specific polysaccharide (OPS) was isolated by mild-acid degradation of the lipopolysaccharide of Vibrio cholerae O9 and studied by carboxyl reduction, sugar and methylation analyses, Smith degradation, and two-dimensional NMR spectroscopy, including COSY, TOCSY, NOESY, and H-detected 1H,(13)C HMQC experiments. The following structure of the pentasaccharide-repeating unit of the OPS was established:     

Comparing bootstrap and posterior probability values in the four-taxon case

Assessment of the reliability of a given phylogenetic hypothesis is an important step in phylogenetic analysis. Historically, the nonparametric bootstrap procedure has been the most frequently used method for assessing the support for specific phylogenetic relationships. The recent employment of Bayesian methods for phylogenetic inference problems has resulted in clade support being expressed in terms of posterior probabilities. We used simulated data and the four-taxon case to explore the relationship between nonparametric bootstrap values (as inferred by maximum likelihood) and posterior probabilities (as inferred by Bayesian analysis). The results suggest a complex association between the two measures. Three general regions of tree space can be identified: (1) the neutral zone, where differences between mean bootstrap and mean posterior probability values are not significant, (2) near the two-branch corner, and (3) deep in the two-branch corner. In the last two regions, significant differences occur between mean bootstrap and mean posterior probability values. Whether bootstrap or posterior probability values are higher depends on the data in support of alternative topologies. Examination of star topologies revealed that both bootstrap and posterior probability values differ significantly from theoretical expectations; in particular, there are more posterior probability values in the range 0.85-1 than expected by theory. Therefore, our results corroborate the findings of others that posterior probability values are excessively high. Our results also suggest that extrapolations from single topology branch-length studies are unlikely to provide any general conclusions regarding the relationship between bootstrap and posterior probability values.