Serological response to Actinobacillus pleuropneumoniae serovar 7 infection in a commercial pig herd

Serological responses to Actinobacillus pleuropneumoniae serovar 7 infection were monitored by enzyme-linked immunosorbent assay in a cohort of 66 pigs between weaning and market. Antibody concentrations were high (63/65 seropositive) at 4 weeks of age but declined to low levels from 8 to 12 weeks. Mean antibody concentrations rose significantly (p less than 0.001) between 12 and 23 weeks. Between 8 and 23 weeks of age, 33 (51.5%) of 64 surviving pigs seroconverted to A pleuropneumoniae serovar 7. Peak antibody concentrations in the seroconverting pigs usually (28/33) occurred at 23 weeks. Seroconversion to A pleuropneumoniae during the grower/finisher phase was not significantly associated (p greater than 0.05) with passive antibody concentrations at 4 weeks of age, lack of vaccination against Mycoplasma hyopneumoniae, or weaning weight. Pleuropneumonic lesions were evident at slaughter in 4 (6.3%) of 64 pigs. A pleuropneumoniae serovar 7 was isolated from 2 of 4 lungs with pleuropneumonia and from another lung with lesions considered typical of enzootic pneumonia.     

Dynamics of Oxidation of a Fe2+-Bearing Aluminosilicate (Basaltic) Melt

Rutherford backscattering spectroscopy (RBS) and microscopy demonstrate that the approximately 1400°C oxidation of levitated droplets of a natural Fe2+-bearing aluminosilicate (basalt) melt occurs by chemical diffusion of Fe2+ and Ca2+ to the free surface of the droplet; internal oxidation of the melt results from the required counterflux of electron holes. Diffusion of an oxygen species is not required. Oxidation causes the droplets to go subsolidus; magnetite (Fe3O4) forms at the oxidation-solidification front with a morphology suggestive of a Liesegang-band nucleation process.     

Neuronal Responses in the Brainstem and Hypothalamic Nuclei Following Insulin Treatment During the Late Follicular Phase in the Ewe

The aim of this study was to determine the neuronal responses following insulin administration during the late follicular phase. Intact ewes were given either saline or insulin (5 IU/kg, i.v.) at 35 h after progesterone withdrawal and killed 3 h later. There was a marked increase in the number of Fos‐positive noradrenergic neurones in the caudal brainstem of insulin‐treated ewes. In the hypothalamic paraventricular nucleus, insulin treatment increased the presence of Fos‐positive corticotrophin‐releasing hormone neurones (from 2% to 98%) and Fos‐positive arginine vasopressin parvocellular neurones (from 2% to 46%). Interestingly, after insulin treatment, despite a general increase in Fos‐positive neurones in the arcuate nucleus (ARC), there was a marked reduction (from 47% to 1%) in Fos‐positive β‐endorphin neurones. Similarly, colocalized Fos and oestradiol receptor (ER) α‐positive neurones decreased in the ARC after insulin (from 7% to 3%). Conversely, in the ventromedial nucleus, ERα‐positive neurones with Fos increased (from 7% to 22%) alongside a general increase in Fos‐positive neurones. Overall, a complex system of neurones in brainstem and hypothalamus is activated following insulin administration during the late follicular phase.     

Images of asteroid 21 Lutetia: a remnant planetesimal from the early Solar System

Images obtained by the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) cameras onboard the Rosetta spacecraft reveal that asteroid 21 Lutetia has a complex geology and one of the highest asteroid densities measured so far, 3.4 ± 0.3 grams per cubic centimeter. The north pole region is covered by a thick layer of regolith, which is seen to flow in major landslides associated with albedo variation. Its geologically complex surface, ancient surface age, and high density suggest that Lutetia is most likely a primordial planetesimal. This contrasts with smaller asteroids visited by previous spacecraft, which are probably shattered bodies, fragments of larger parents, or reaccumulated rubble piles.     

Factors affecting discharge and germination of ascospores of Hypoxylon mediterraneum (De Not.) Mill.

Discharge and germination of ascospores of Hypoxylon mediterraneum (=Biscogniauxia mediterranea (De Not.) O. Kuntze) were studied. Discharge and germination of ascospores depend on the presence of water or high relative air humidity. Ascospores are ejected from stromata in forest for most of the year following periods of high precipitation. H. mediterraneum ascospores germinated under a wide range of biotic and abiotic conditions. The optimal temperature for germination was 35°C, but 25 and 30°C were still favourable, while 20 and 40°C reduced germination. Ascospores kept at 5°C were able to germinate after short exposure to temperatures ranging from 20 to 35°C. Germination rate depended on the ascospore density in in vitro experiments, and was highest at 10⁶ ascospore/ml. Tissues of some host plants greatly increased germination rate. In vivo, ascospores germinated better on wounded axillary tissues than on unwounded ones.     

Effects of FGF10 on Bovine Oocyte Meiosis Progression,Apoptosis, Embryo Development and Relative Abundance of Developmentally Important Genes In Vitro

Fibroblast growth factor (FGF10) acts at the cumulus oocyte complex, increasing the expression of cumulus cell expansion‐related genes and oocyte competency genes. We tested the hypothesis that addition of FGF10 to the maturation medium improves oocyte maturation, decreases the percentage of apoptotic oocytes and increases development to the blastocyst stage while increasing the relative abundance of developmentally important genes (COX2, CDX2 and PLAC8). In all experiments, oocytes were matured for 22 h in TCM‐199 supplemented with 0, 2.5, 10 or 50 ng/ml FGF10. In Experiment 1, after maturation, oocytes were stained with Hoechst to evaluate meiosis progression (metaphase I, intermediary phases and extrusion of the first polar body) and submitted to the TUNEL assay to evaluate apoptosis. In Experiment 2, oocytes were fertilized and cultured to the blastocyst stage. Blastocysts were frozen for analysis of COX2, CDX2 and PLAC8 relative abundance. In Experiment 1, 2.5 ng/ml FGF10 increased (p < 0.05) the percentage of oocytes with extrusion of the first polar body (35%) compared to 0, 10 and 50 ng/ml FGF10 (21, 14 and 12%, respectively) and FGF10 decreased the percentage of oocytes that were TUNEL positive in all doses studied. In Experiment 2, there was no difference in the percentage of oocytes becoming blastocysts between treatments and control. Real‐time RT‐PCR showed a tendency of 50 ng/ml FGF10 to increase the relative abundance of COX2 and PLAC8 and of 10 ng/ml FGF10 to increase CDX2. In conclusion, the addition of FGF10 to the oocyte maturation medium improves oocyte maturation in vitro, decreases the percentage of apoptotic oocytes and tends to increase the relative abundance of developmentally important genes.     

Chaotic Dynamics in an Insect Population

A nonlinear demographic model was used to predict the population dynamics of the flour beetle Tribolium under laboratory conditions and to establish the experimental protocol that would reveal chaotic behavior. With the adult mortality rate experimentally set high, the dynamics of animal abundance changed from equilibrium to quasiperiodic cycles to chaos as adult-stage recruitment rates were experimentally manipulated. These transitions in dynamics corresponded to those predicted by the mathematical model. Phase-space graphs of the data together with the deterministic model attractors provide convincing evidence of transitions to chaos.