Immunohistochemical visualisation of the enteric nervous system architecture in the germ-free piglets

Journal of Molecular Histology - The enteric nervous system (ENS), considered as separate branch of the autonomic nervous system, is located throughout the length of the gastrointestinal tract as a...     

Demographic effects of canine parvovirus on a free-ranging wolf population over 30 years

We followed the course of canine parvovirus (CPV) antibody prevalence in a subpopulation of wolves (Canis lupus) in northeastern Minnesota from 1973, when antibodies were first detected, through 2004. Annual early pup survival was reduced by 70%, and wolf population change was related to CPV antibody prevalence. In the greater Minnesota population of 3,000 wolves, pup survival was reduced by 40-60%. This reduction limited the Minnesota wolf population rate of increase to about 4% per year compared with increases of 16-58% in other populations. Because it is young wolves that disperse, reduced pup survival may have caused reduced dispersal and reduced recolonization of new range in Minnesota.     

Movements of wolves at the northern extreme of the species' range, including during four months of darkness

Information about wolf (Canis lupus) movements anywhere near the northern extreme of the species'' range in the High Arctic (>75°N latitude) are lacking. There, wolves prey primarily on muskoxen (Ovibos moschatus) and must survive 4 months of 24 hr/day winter darkness and temperatures reaching −53 C. The extent to which wolves remain active and prey on muskoxen during the dark period are unknown, for the closest area where information is available about winter wolf movements is >2,250 km south. We studied a pack of ≥20 wolves on Ellesmere Island, Nunavut, Canada (80°N latitude) from July 2009 through mid-April 2010 by collaring a lead wolf with a Global Positioning System (GPS)/Argos radio collar. The collar recorded the wolf''s precise locations at 6:00 a.m. and 6:00 p.m. daily and transmitted the locations by satellite to our email. Straight-line distances between consecutive 12-hr locations varied between 0 and 76 km. Mean (SE) linear distance between consecutive locations (n = 554) was 11 (0.5) km. Total minimum distance traveled was 5,979 km, and total area covered was 6,640 km², the largest wolf range reported. The wolf and presumably his pack once made a 263-km (straight-line distance) foray to the southeast during 19–28 January 2010, returning 29 January to 1 February at an average of 41 km/day straight-line distances between 12-hr locations. This study produced the first detailed movement information about any large mammal in the High Arctic, and the average movements during the dark period did not differ from those afterwards. Wolf movements during the dark period in the highest latitudes match those of the other seasons and generally those of wolves in lower latitudes, and, at least with the gross movements measurable by our methods, the 4-month period without direct sunlight produced little change in movements.     

Transmission of Neospora caninum between wild and domestic animals

To determine whether deer can transmit Neospora caninum, brains of naturally infected white-tailed deer (Odocoileus virginianus) were fed to 4 dogs; 2 of these dogs shed oocysts. Oocysts from 1 of the dogs were tested by polymerase chain reaction and found to be positive for N. caninum and negative for Hammondia heydorni. The internal transcribed spacer 1 sequence of the new strain (designated NC-deer1) was identical to N. caninum from domestic animals, indicating that N. caninum is transmitted between wild and domestic animals, often enough to prevent divergent evolution of isolated populations of the parasite. NC-deerl oocysts were administered to a calf that developed a high antibody titer, providing evidence that N. caninum from wildlife can infect cattle. In addition, N. caninum antibody seroprevalence was detected in 64/164 (39%) free-ranging gray wolves (Canis lupus), 12/113 (11%) coyotes (Canis latrans), 50/193 (26%) white-tailed deer, and 8/61 (13%) moose (Alces alces). These data are consistent with a sylvatic transmission cycle of N. caninum between cervids and canids. We speculate that hunting by humans favors the transmission of N. caninum from deer to canids, because deer carcasses are usually eviscerated in the field. Infection of canids in turn increases the risk of transmitting the parasite to domestic livestock.     

3D Architectural Modelling of Aerial Photomorphogenesis in White Clover (Trifolium repens L.) using L-systems

The objective of this work was to construct a model of aerialdevelopment of clover that takes into account morphogeneticresponses to the light environment, and to use it to analyseand understand these processes in terms of signal perceptionand integration. The plant model was interfaced with a MonteCarlo model that determines photosynthetically active radiation(PAR) and red/far-red ratio (R/FR) throughout the canopy, takinginto account the absorption, reflection and transmission oflight by individual leaves. Light intensity and quality weresensed by the plant model at discrete time intervals and atdiscrete sites of perception: apices, emerging internodes andpetiole tips. This input regulated the final size of internodesand leaves, the vertical positioning of leaves, and the branchingdelay. The empirical relations (regression functions) quantifyingthis regulation were derived from data reported in the literatureand original measurements. Simulations produced realistic visualizationsand quantitative characterizations of the modelled plants fordifferent light treatments. These results were in general agreementwith observations of real plants growing under similar conditions,suggesting that the dependence of organ size and position onlight treatments can be regarded as an integration of the responsesof individual plant organs to their local light environment.The model is used to describe the regulation of branch appearanceand the impact of self-shading on plant morphogenesis as a functionof local light environment. Copyright 2000 Annals of BotanyCompany Clover, Trifolium repens L, photomorphogenesis, plant architecture, L-system, modelling, Monte-Carlo method, competition for light, red : far-red ratio, irradiance, light quality, leaf size, self-shading     

Energy metabolism and hematology of white-tailed deer fawns.

Resting metabolic rates, weight gains and hematologic profiles of six newborn, captive white-tailed deer (Odocoileus virginianus) fawns (four females, two males) were determined during the first 3 mo of life. Estimated mean daily weight gain of fawns was 0.2 kg. The regression equation for metabolic rate was: Metabolic rate (kcal/kg0.75/day) = 56.1 +/- 1.3 (age in days), r = 0.65, P less than 0.001). Regression equations were also used to relate age to red blood cell count (RBC), hemoglobin concentration (Hb), packed cell volume, white blood cell count, mean corpuscular volume, mean corpuscular hemoglobin concentration (MCHC), and mean corpuscular hemoglobin. The age relationships of Hb, MCHC, and smaller RBC's were indicative of an increasing and more efficient oxygen-carrying and exchange capacity to fulfill the increasing metabolic demands for oxygen associated with increasing body size.     

Comprehensive In Vitro Toxicity Testing of a Panel of Representative Oxide Nanomaterials: First Steps towards an Intelligent Testing Strategy

Nanomaterials (NMs) display many unique and useful physico-chemical properties. However, reliable approaches are needed for risk assessment of NMs. The present study was performed in the FP7-MARINA project, with the objective to identify and evaluate in vitro test methods for toxicity assessment in order to facilitate the development of an intelligent testing strategy (ITS). Six representative oxide NMs provided by the EC-JRC Nanomaterials Repository were tested in nine laboratories. The in vitro toxicity of NMs was evaluated in 12 cellular models representing 6 different target organs/systems (immune system, respiratory system, gastrointestinal system, reproductive organs, kidney and embryonic tissues). The toxicity assessment was conducted using 10 different assays for cytotoxicity, embryotoxicity, epithelial integrity, cytokine secretion and oxidative stress. Thorough physico-chemical characterization was performed for all tested NMs. Commercially relevant NMs with different physico-chemical properties were selected: two TiO₂ NMs with different surface chemistry – hydrophilic (NM-103) and hydrophobic (NM-104), two forms of ZnO – uncoated (NM-110) and coated with triethoxycapryl silane (NM-111) and two SiO₂ NMs produced by two different manufacturing techniques – precipitated (NM-200) and pyrogenic (NM-203). Cell specific toxicity effects of all NMs were observed; macrophages were the most sensitive cell type after short-term exposures (24-72h) (ZnO>SiO₂>TiO₂). Longer term exposure (7 to 21 days) significantly affected the cell barrier integrity in the presence of ZnO, but not TiO₂ and SiO₂, while the embryonic stem cell test (EST) classified the TiO₂ NMs as potentially ‘weak-embryotoxic’ and ZnO and SiO₂ NMs as ‘non-embryotoxic’. A hazard ranking could be established for the representative NMs tested (ZnO NM-110 > ZnO NM-111 > SiO₂ NM-203 > SiO₂ NM-200 > TiO₂ NM-104 > TiO₂ NM-103). This ranking was different in the case of embryonic tissues, for which TiO₂ displayed higher toxicity compared with ZnO and SiO₂. Importantly, the in vitro methodology applied could identify cell- and NM-specific responses, with a low variability observed between different test assays. Overall, this testing approach, based on a battery of cellular systems and test assays, complemented by an exhaustive physico-chemical characterization of NMs, could be deployed for the development of an ITS suitable for risk assessment of NMs. This study also provides a rich source of data for modeling of NM effects.     

Sex and the Single Vole: Effects of Social Grouping on Prairie Vole Reproductive Success

Prairie voles (Microtus ochrogaster) have a mating system that is primarily monogamous with paired males and females together defending breeding space against intruders of either sex. Breeding success may be affected when other adults intrude on the territorial space of pairs. We conducted an experiment to determine the impact of additional members of either sex on reproductive success of pairs. In laboratory arenas, we formed pairs (1F:1M) and two kinds of triad (2F:1M, 1F:2M). Females in pairs had the highest conception rates, litter sizes and survival of litters. Females in 1F:2M groups had slightly reduced litter sizes and reduced numbers of weanlings, and some females had litters sired by both males. Females in 2F:1M groups had low conception rates and the smallest litters, and >35% of their litters suffered infanticide; in no case did both females become pregnant. Throughout the trials, individuals of the sex doubly represented in triads were more likely to die than were individuals of the sex singly represented. We conclude that there may be fitness costs associated with the presence of unrelated supernumerary adults during gestation and lactation.     

Postconditioning and Anticonditioning: Possibilities to Interfere to Evoked Apoptosis

The aim of this study was to validate the ability of postconditioning, used 2 days after kainate intoxication, to protect selectively vulnerable hippocampal CA1 neurons against delayed neuronal death. Kainic acid (8 mg/kg, i.p.) was used to induce neurodegeneration of pyramidal CA1 neurons in rat hippocampus. Fluoro Jade B, the specific marker of neurodegeneration, and NeuN, a specific neuronal marker were used for visualization of changes 7 days after intoxication without and with delayed postconditioning (norepinephrine, 3.1 μmol/kg i.p., 2 days after kainate administration) and anticonditioning (Extract of Ginkgo biloba, 40 mg/kg p.o used simultaneously with kainate). Morris water maze was used on 6th and 7th day after kainate to test learning and memory capabilities of animals. Our results confirm that postconditioning if used at right time and with optimal intensity is able to prevent delayed neuronal death initiated not only by ischemia but kainate intoxication, too. The protective effect of repeated stress–postconditioning was suppressed if extract of Ginkgo biloba (EGb 761, 40 mg/kg p.o.) has been administered together with kainic acid. It seems that combination of lethal stress and antioxidant treatment blocks the activation of endogenous protecting mechanism known as ischemic tolerance, aggravates neurodegeneration and, after repeated stress is able to cause cumulative damage. This observation could be very valuable in situation when the aim of treatment is elimination of unwanted cell population from the organism.