Multi-scale effect of landscape processes and habitat quality on newt abundance: Implications for conservation

Recent studies in population dynamics suggest that landscape processes and habitat quality act at different scales on population abundances, but very few have modelled their simultaneous effects. However, at a time of large declines in natural populations, it is essential to understand such multivariate components. We tested the hypothesis that natural populations of palmate newts (Triturus helveticus) are affected on three scales: breeding patch (pond), habitat complementation (terrestrial cover), and metapopulation structure (density of ponds, surrounding populations). We conducted our survey in 130 ponds from southern France (Larzac) and analysed data with generalized additive models (GAM). Two main novel results emerge from these models: (1) the three landscape scales have significant effects on newt abundance, with more newts in deep, vegetated ponds, devoid of fish and surrounded by wooded areas and inhabited ponds; (2) the quality of the surrounding breeding patches is of primary importance in determining the abundance at core sites in a complex way: high abundances are associated positively with high densities of inhabited ponds, but negatively with the number of surrounding ponds. Deforestation, invasive species and abandonment of ponds all have negative impacts on the persistence of palmate newt populations. Future studies should encompass landscapes at different scales and incorporate the habitat quality in surrounding sites to better understand population dynamics and provide adequate conservation measures.     

Characterization of suspended particulate matter in the Moselle River (Lorraine,France): evolution along the course of the river and in different hydrologic regimes

Purpose

Suspended particulate matter (SPM) plays an important role in the transport and fate of contaminants in the environment. To better understand the relationships between contaminants and SPM, SPM properties, and their variations with flow regime, river size, land use, and season should be considered.

Materials and methods

The grain size distribution, elemental composition, and mineralogy of SPM from different stations along the Moselle River (Lorraine, France) were investigated at the particle scale during different flow regimes. The resulting data were compared with the elemental composition of the dissolved compartment to understand the role of particles in element transport.

Results and discussion

The grain size distribution, elemental composition, and mineralogy of SPM along the Moselle River and during different flow regimes showed only slight variations, except for the Fensch and Orne tributaries, two rivers that were impacted by inherited steel-making industrialization and different land use. In the Moselle River, SPM mainly consisted of clay minerals, while in Fensch and Orne Rivers, SPM mainly consisted of multiple types of anthropogenic particles. The diffuse urbanization gradient was hardly recognized based on the Trace Metal Element (TMEs) content in the river SPM, while the rivers impacted by the steel industries had greater TME contents. Finally, the TME content in the Moselle SPM was more strongly influenced by water flow than by the position of sampling on the linear reach of the Moselle River. The partitioning of TMEs in the particles and water at the main Moselle station (Frouard) revealed that SPM predominantly contributed to TMEs transport.

Conclusions

This study confirmed that catchment geology greatly contributed to the SPM composition in the mean-sized rivers. In addition, the high anthropogenic pressure could be deciphered for small tributaries. Furthermore, this study allowed us to observe the high contribution of particles to TMEs and Rare Earth Element (REEs) transportation.

     

Geographical distribution of Alzheimer's disease cases at birth and the geochemical profile of Saguenay-Lac-Saint-Jean/Québec,Canada (image project)

Accepting as founded the hypothesis of a multifactorial origin for the Alzheimer's disease (AD), we explore the possible links between the geographical distribution of AD cases according to their birth place and the geochemical profile of the Saguenay-Lac-Saint-Jean (SLSJ) territory in the province of Québec. The method used for factor analysis of correspondances (FAC) and another one based on the differences between the residential and municipal geochemical concentrations (DRMC) have been used for this purpose. The geochemical matrix of SLSJ relates the highest concentrations of nickel, copper and zinc to the sector surrounding the Jonquière municipality. Moreover, high concentrations of iron, lead and manganese were found in the northern sector of the Lac Saint-Jean. The DRMC method corroborates this strong correlation between iron, lead and manganese. Furthermore, these concentrations do not differ from the north-american geochemical standards. No single geochemical element seems to be associate with the spatial distribution of cases. It is, however, still possible that a certain synergistic effect between two or several elements could be implied in the development of the disease. According to the results of the soil analysis, there does not seem to be any association between the spatial distribution of cases and the concentration of aluminum, a chemical element that has been thought to be implied in the etiology of AD. These results are compared with those obtained by other workers in the micronesian islands, where abnormally high frequencies of amyotrophic lateral sclerosis and parkinsonism dementia have already been observed.     

Das Blutgefäßsystem des Enddarms vom Schwein (Sus scrofa f. domestica)

The circulatory system of the large intestine of 27 pigs was examined by means of corrosion anatomy (vascular casts), histology and electron microscopy. The results were as follows: The Aa. et Vv. breves et longae leave the mesenteric vessels and reach the wall of the intestine at the mesenteric margin. The short vessels enter the deeper layers of the wall, whereas the Aa. et Vv. longae, by taking a variable subserous course, reach the submucosa af ter penetrating the muscular layers. The tela submucosa contains an arterial and a venous vascular plexus. Where the submucosa is larger, there is a three-dimensional vascular network, a deep and superficial vascular plexus that are closely interconnected. The deep plexus is applied to the inner circular muscles, whereas the superficial plexus is adjacent to the muscularis mucosae. The deep arterial plexus receives its af flux from the Aa. breves et longae and provides part of the circular muscle layers with recurrent muscle branches. The vascularization of the mucosa is derived from the (superficial) submucosal plexus. The arteries that ascend the tunica mucosa ramify, in the form of a brush, into some arterioles. In the basal part of the mucosa, they turn into a periglandular capillary system, i.e. a network around each Lieberkühn crypt. Close to the lumen, a polygonal subepithelial capillary system is formed. Below the epithelium of the mucosal surf ace, the capillaries turn into postcapillary venules. These are running vertically through the submucosa, with few infiowing side branches, and finally enter the submucosal plexus. An intermuscular plexus is formed by anastomoses between the circular and the longitudinal muscular layers from the branches of the subserous-submucosal connections. This intermuscular plexus provides the capillaries for the tunica muscularis. The subepithelial capillaries are, above all, furnished with a so-called fenestrated endothelium, whereas the capillaries of the pericryptal mucosa mainly show a continuous endothelium. The latter contains multiple vesicles that can fuse to form transcytoplasmic channels. In the wall of the large intestine of the pig, there are no sure indications as to the existence of either arterio-venous anastomoses or haemodynamic regulatory structures.     

A Study of the Oral Toxicity of Calcium Chloride in Dairy Cows

The effects of oral administration of calcium chloride solutions to dairy cows were studied. When a 0.3 per cent solution was given ad libitum, and as the sole source of water for a period of 75 days, we observed no significant changes in feed consumption, body weight or milk production. The average daily water intake was increased by approximately 20 per cent, and signs of slight gastro-intestinal irritation were seen. No major changes in blood hemoglobin levels, hematocrits, total and differential white cell counts or thrombocyte numbers could be attributed to the treatment. We observed no significant effect on the serum calcium, chloride, magnesium, potassium, or sodium content. The level of inorganic phosphate in the serum rose to higher, but still normal values. During the entire experiment the urine pH was abnormally acid for dairy cows. Electrocardiograms were taken after 45 days of calcium chloride administration, and they appeared normal. When 0.1 and 0.2 per cent solutions were given as the sole source of water for a period of 81 days, the cows remained in good condition, and we observed no changes in appetite, body weight or milk production. In general, dairy cows will refuse to drink calcium chloride solutions when the concentration exceeds 0.5 per cent, even when they have been deprived of water for 18-24 hours. On the other hand, since the administration of lower concentrations for periods of 75 and 81 days did not cause any clinical sign of disease, it seems that on farms where more than one source of water are usually available, poisoning of dairy cattle by calcium chloride in solution is quite unlikely.     

Chicken anemia virus induced apoptosis: underlying molecular mechanisms

In 1990, the chicken anemia virus (CAV) genome was cloned by us and proven to be representative for CAV isolates worldwide. This genome contains unique promoter/enhancer replication elements and genes. Upon infection of its target cells, CAV replicates via a double-stranded (ds) DNA intermediate. From this ds CAV molecule, a single mRNA is transcribed, which encodes for three distinct proteins VP1, VP2, and VP3 or apoptin. Its capsid contains only the VP1 protein. However, for the production of the neutralizing epitope, co-synthesis of VP1 and VP2 are needed. CAV genomes with mutations in the 12 bp insert of the promoter/enhancer region were shown to produce immunogenic functional CAV particles. Mutations in these and other regulatory elements of CAV might also decrease its virus load resulting in a reduced pathogenic effect. CAV causes fatal cytopathogenic effects in e.g. chicken thymocytes via apoptosis. Under in vitro conditions, CAV replicates only in transformed chicken cell lines, which indicates that at least a part of the CAV life-cycle requires transformed-like cellular events. In these transformed cell lines, the synthesis of the apoptin protein alone mimics the CAV-induced apoptosis, whereas the VP2 protein also harbors some apoptotic activity. Extensive studies on apoptin resulted in the characterization of domains essential for its apoptotic activity and nuclear localization, which seems to be related with its ability to induce apoptosis. Therefore, both VP2 and apoptin are of interest in reducing the pathogenicity of CAV infections. A series of biomedical studies on apoptin have been carried out in human cell systems, which are informative about the mechanism of CAV-induced apoptosis in chicken (transformed) cells. Synthesis of apoptin alone induces apoptosis in various human transformed and/or tumorigenic cell lines, but not in normal human diploid cells. A striking difference in the cellular localization of apoptin was observed in human normal diploid cells versus tumor cells. In all tumor cells, apoptin is located mainly in the heterochromatic regions of the nucleus, whereas in normal cells it is present in peri-nuclear structures. Apoptin contains a bipartite nuclear localization signal, and one domain that resemble a nuclear export signal. Elucidation of parts of the apoptin-induced apoptotic pathway revealed unique characteristics: apoptin-induced apoptosis is independent of the tumor suppressor p53. The anti-apoptotic protein Bcl-2 does not inhibit but even accelerates apoptin-induced apoptosis in tumor cells, whereas over expression of Bcl-2 in normal cells has no effect on the apoptin activity. Upstream caspases are not involved, whereas downstream caspase 3 is, but seems not to be essential. A number of novel proteins were shown to interact with apoptin in transformed cells. Future studies of apoptin, VP2 and related cellular proteins in chicken cells will unravel the regulatory aspects of CAV-induced apoptosis.     

Idiopathic prolapse of 1 uterine horn in a yearling filly

A yearling filly was presented for protrusion of a mass at the vulvar margins. A diagnosis of prolapse of the right uterine horn was made after vaginoscopy, transrectal palpation, and ultrasonography. It was confirmed later by biopsy of the tissue. Recovery was uneventful after easy replacement of the uterine horn.     

Global mineralogical and aqueous mars history derived from OMEGA/Mars Express data

Global mineralogical mapping of Mars by the Observatoire pour la Mineralogie, l'Eau, les Glaces et l'Activité (OMEGA) instrument on the European Space Agency's Mars Express spacecraft provides new information on Mars' geological and climatic history. Phyllosilicates formed by aqueous alteration very early in the planet's history (the "phyllocian" era) are found in the oldest terrains; sulfates were formed in a second era (the "theiikian" era) in an acidic environment. Beginning about 3.5 billion years ago, the last era (the "siderikian") is dominated by the formation of anhydrous ferric oxides in a slow superficial weathering, without liquid water playing a major role across the planet.     

Tectonic uplift and Eastern Africa aridification

The history of Eastern African hominids has been linked to a progressive increase of open grassland during the past 8 million years. This trend was explained by global climatic processes, which do not account for the massive uplift of eastern African topography that occurred during this period. Atmosphere and biosphere simulations quantify the role played by these tectonic events. The reduced topographic barrier before 8 million years ago permitted a zonal circulation with associated moisture transport and strong precipitation. Our results suggest that the uplift itself led to a drastic reorganization of atmospheric circulation, engendering the strong aridification and paleoenvironmental changes suggested by the data.