Local Mechanical Stimuli Regulate Bone Formation and Resorption in Mice at the Tissue Level
; Ruffoni, Davide ; et al
in PLOS ONE (2013), 8(4), 62172-12
Bone is able to react to changing mechanical demands by adapting its internal microstructure through bone forming and resorbing cells. This process is called bone modeling and remodeling. It is evident ... [more ▼]
Bone is able to react to changing mechanical demands by adapting its internal microstructure through bone forming and resorbing cells. This process is called bone modeling and remodeling. It is evident that changes in mechanical demands at the organ level must be interpreted at the tissue level where bone (re) modeling takes place. Although assumed for a long time, the relationship between the locations of bone formation and resorption and the local mechanical environment is still under debate. The lack of suitable imaging modalities for measuring bone formation and resorption in vivo has made it difficult to assess the mechanoregulation of bone three-dimensionally by experiment. Using in vivo micro-computed tomography and high resolution finite element analysis in living mice, we show that bone formation most likely occurs at sites of high local mechanical strain (p<0.0001) and resorption at sites of low local mechanical strain (p<0.0001). Furthermore, the probability of bone resorption decreases exponentially with increasing mechanical stimulus (R-2 = 0.99) whereas the probability of bone formation follows an exponential growth function to a maximum value (R-2 = 0.99). Moreover, resorption is more strictly controlled than formation in loaded animals, and ovariectomy increases the amount of non-targeted resorption. Our experimental assessment of mechanoregulation at the tissue level does not show any evidence of a lazy zone and suggests that around 80% of all (re) modeling can be linked to the mechanical microenvironment. These findings disclose how mechanical stimuli at the tissue level contribute to the regulation of bone adaptation at the organ level. [less ▲]Detailed reference viewed: 12 (2 ULg)
Behaviours Associated with Acoustic Communication in Nile Tilapia (Oreochromis niloticus)
; Poncin, Pascal ; Denoël, Mathieu et al
in PLoS ONE (2013), 8(4), 61467Detailed reference viewed: 67 (18 ULg)
Mithramycin Exerts an Anti-Myeloma Effect and Displays Anti-Angiogenic Effects through Up-Regulation of Anti-Angiogenic Factors.
Otjacques, Eléonore ; Binsfeld, Marilène ; Rocks, Natacha et al
in PLoS ONE (2013), 8(5), 62818
Mithramycin (MTM), a cytotoxic compound, is currently being investigated for its anti-angiogenic activity that seems to be mediated through an inhibition of the transcription factor SP1. In this study we ... [more ▼]
Mithramycin (MTM), a cytotoxic compound, is currently being investigated for its anti-angiogenic activity that seems to be mediated through an inhibition of the transcription factor SP1. In this study we evaluated its anti-myeloma effects in the syngenic 5TGM1 model in vitro as well as in vivo. In vitro, MTM inhibited DNA synthesis of 5TGM1 cells with an IC50 of 400 nM and induced an arrest in cell cycle progression at the G1/S transition point. Western-blot revealed an up-regulation of p53, p21 and p27 and an inhibition of c-Myc, while SP1 remained unaffected. In rat aortic ring assays, a strong anti-angiogenic effect was seen, which could be explained by a decrease of VEGF production and an up-regulation of anti-angiogenic proteins such as IP10 after MTM treatment. The administration of MTM to mice injected with 5TGM1 decreased 5TGM1 cell invasion into bone marrow and myeloma neovascularisation. These data suggest that MTM displays anti-myeloma and anti-angiogenic effects that are not mediated by an inhibition of SP1 but rather through c-Myc inhibition and p53 activation. [less ▲]Detailed reference viewed: 34 (5 ULg)
The Importance of Encoding-Related Neural Dynamics in the Prediction of Inter-Individual Differences in Verbal Working Memory Performance
Majerus, Steve ; Salmon, Eric ; Attout, Lucie
in PLoS ONE (2013), 8(7),
Studies of brain-behaviour interactions in the field of working memory (WM) have associated WM success with activation of a fronto-parietal network during the maintenance stage, and this mainly for visuo ... [more ▼]
Studies of brain-behaviour interactions in the field of working memory (WM) have associated WM success with activation of a fronto-parietal network during the maintenance stage, and this mainly for visuo-spatial WM. Using an inter-individual differences approach, we demonstrate here the equal importance of neural dynamics during the encoding stage, and this in the context of verbal WM tasks which are characterized by encoding phases of long duration and sustained attentional demands. Participants encoded and maintained 5-word lists, half of them containing an unexpected word intended to disturb WM encoding and associated task-related attention processes. We observed that inter-individual differences in WM performance for lists containing disturbing stimuli were related to activation levels in a region previously associated with task-related attentional processing, the left intraparietal sulcus (IPS), and this during stimulus encoding but not maintenance; functional connectivity strength between the left IPS and lateral prefrontal cortex (PFC) further predicted WM performance. This study highlights the critical role, during WM encoding, of neural substrates involved in task-related attentional processes for predicting inter-individual differences in verbal WM performance, and, more generally, provides support for attention-based models of WM. © 2013 Majerus et al. [less ▲]Detailed reference viewed: 37 (4 ULg)
Sputum IgE and Cytokines in Asthma: Relationship with Sputum Cellular Profile.
Manise, Maïté ; ; et al
in PLoS ONE (2013), 8(3), 58388
BACKGROUND: Local IgE production may play a role in asthma pathogenesis. The aim of the study was to assess sputum total IgE and cytokines in asthmatics according to sputum cellular phenotype. METHODS: We ... [more ▼]
BACKGROUND: Local IgE production may play a role in asthma pathogenesis. The aim of the study was to assess sputum total IgE and cytokines in asthmatics according to sputum cellular phenotype. METHODS: We studied 122 subjects including 22 non atopic healthy subjects, 41 eosinophilic (sputum eosinophils >/=3%), 16 neutrophilic (sputum neutrophils >76%) and 43 pauci-granulocytic asthmatics (sputum eosinophils <3% and sputum neutrophils </=76%) recruited from the asthma clinic at CHU Liege. Sputum supernatant total IgE (tIgE) was measured by ImmunoCAP and sputum supernatant cytokines (IL-4, IL-5, IL-6, IL-10, IL-13, IL-17, IFN-gamma and TNF-alpha) were measured with the Luminex xMAP Technology by using commercially available Fluorokine MAP kits. RESULTS: After concentrating sputum samples, total IgE was detectable in the majority of subjects. Sputum IgE was raised in asthmatics when compared to healthy subjects. Overall, asthmatics did not significantly differ from healthy subjects with respect to cytokine levels. The eosinophilic asthma phenotype, however, was characterised by raised sputum tIgE, IL-5 and IL-13 compared to healthy subjects (p<0.001, p<0.001 and p<0.05 respectively) and pauci-granulocytic asthma (p<0.01, p<0.001 and p<0.05 respectively) and raised IL-5 compared to neutrophilic asthma (p<0.01). When patients were classified according to sputum IgE levels, it appeared that IL-5, IL-6, IL-17 and TNF-alpha sputum supernatant levels were raised in the "IgE high" asthmatics (IgE >/=0.1 kU/l) when compared to "IgE low" asthmatics (IgE<0.1 kU/l). CONCLUSION: The eosinophilic asthma phenotype was associated with raised sputum IgE and a Th2 cytokine profile. Raised sputum IgE was associated with a heterogeneous cytokine overproduction. [less ▲]Detailed reference viewed: 23 (4 ULg)
Devastating Decline of Forest Elephants in Central Africa.
; ; et al
in PLoS ONE (2013), 8(3),
African forest elephants– taxonomically and functionally unique–are being poached at accelerating rates, but we lack range-wide information on the repercussions. Analysis of the largest survey dataset ... [more ▼]
African forest elephants– taxonomically and functionally unique–are being poached at accelerating rates, but we lack range-wide information on the repercussions. Analysis of the largest survey dataset ever assembled for forest elephants (80 foot-surveys; covering 13,000 km; 91,600 person-days of fieldwork) revealed that population size declined by ca. 62% between 2002–2011, and the taxon lost 30% of its geographical range. The population is now less than 10% of its potential size, occupying less than 25% of its potential range. High human population density, hunting intensity, absence of law enforcement, poor governance, and proximity to expanding infrastructure are the strongest predictors of decline. To save the remaining African forest elephants, illegal poaching for ivory and encroachment into core elephant habitat must be stopped. In addition, the international demand for ivory, which fuels illegal trade, must be dramatically reduced. [less ▲]Detailed reference viewed: 21 (3 ULg)
Molecular reclassification of Crohn's disease: a cautionary note on population stratification.
; ; Mahachie John, Jestinah et al
in PloS one (2013), 8(10), 77720
Complex human diseases commonly differ in their phenotypic characteristics, e.g., Crohn's disease (CD) patients are heterogeneous with regard to disease location and disease extent. The genetic ... [more ▼]
Complex human diseases commonly differ in their phenotypic characteristics, e.g., Crohn's disease (CD) patients are heterogeneous with regard to disease location and disease extent. The genetic susceptibility to Crohn's disease is widely acknowledged and has been demonstrated by identification of over 100 CD associated genetic loci. However, relating CD subphenotypes to disease susceptible loci has proven to be a difficult task. In this paper we discuss the use of cluster analysis on genetic markers to identify genetic-based subgroups while taking into account possible confounding by population stratification. We show that it is highly relevant to consider the confounding nature of population stratification in order to avoid that detected clusters are strongly related to population groups instead of disease-specific groups. Therefore, we explain the use of principal components to correct for population stratification while clustering affected individuals into genetic-based subgroups. The principal components are obtained using 30 ancestry informative markers (AIM), and the first two PCs are determined to discriminate between continental origins of the affected individuals. Genotypes on 51 CD associated single nucleotide polymorphisms (SNPs) are used to perform latent class analysis, hierarchical and Partitioning Around Medoids (PAM) cluster analysis within a sample of affected individuals with and without the use of principal components to adjust for population stratification. It is seen that without correction for population stratification clusters seem to be influenced by population stratification while with correction clusters are unrelated to continental origin of individuals. [less ▲]Detailed reference viewed: 15 (1 ULg)
Rapid Plant Invasion in Distinct Climates Involves Different Sources of Phenotypic Variation
Monty, Arnaud ; Bizoux, Jean-Philippe ; et al
in PLoS ONE (2013), 8(1), 55627
When exotic species spread over novel environments, their phenotype will depend on a combination of different processes, including phenotypic plasticity (PP), local adaptation (LA), environmental maternal ... [more ▼]
When exotic species spread over novel environments, their phenotype will depend on a combination of different processes, including phenotypic plasticity (PP), local adaptation (LA), environmental maternal effects (EME) and genetic drift (GD). Few attempts have been made to simultaneously address the importance of those processes in plant invasion. The present study uses the well-documented invasion history of Senecio inaequidens (Asteraceae) in southern France, where it was introduced at a single wool-processing site. It gradually invaded the Mediterranean coast and the Pyrenean Mountains, which have noticeably different climates. We used seeds from Pyrenean and Mediterranean populations, as well as populations from the first introduction area, to explore the phenotypic variation related to climatic variation. A reciprocal sowing experiment was performed with gardens under Mediterranean and Pyrenean climates. We analyzed climatic phenotypic variation in germination, growth, reproduction, leaf physiology and survival. Genetic structure in the studied invasion area was characterized using AFLP. We found consistent genetic differentiation in growth traits but no home-site advantage, so weak support for LA to climate. In contrast, genetic differentiation showed a relationship with colonization history. PP in response to climate was observed for most traits, and it played an important role in leaf trait variation. EME mediated by seed mass influenced all but leaf traits in a Pyrenean climate. Heavier, earlier-germinating seeds produced larger individuals that produced more flower heads throughout the growing season. However, in the Mediterranean garden, seed mass only influenced the germination rate. The results show that phenotypic variation in response to climate depends on various ecological and evolutionary processes associated with geographical zone and life history traits. Seeing the relative importance of EME and GD, we argue that a “local adaptation vs. phenotypic plasticity” approach is therefore not sufficient to fully understand what shapes phenotypic variation and genetic architecture of invasive populations. [less ▲]Detailed reference viewed: 41 (12 ULg)
Octarellin VI: using rosetta to design a putative artificial (beta/alpha)8 protein.
Figueroa Yévenes, Maximiliano ; ; et al
in PloS one (2013), 8(8), 71858
The computational protein design protocol Rosetta has been applied successfully to a wide variety of protein engineering problems. Here the aim was to test its ability to design de novo a protein adopting ... [more ▼]
The computational protein design protocol Rosetta has been applied successfully to a wide variety of protein engineering problems. Here the aim was to test its ability to design de novo a protein adopting the TIM-barrel fold, whose formation requires about twice as many residues as in the largest proteins successfully designed de novo to date. The designed protein, Octarellin VI, contains 216 residues. Its amino acid composition is similar to that of natural TIM-barrel proteins. When produced and purified, it showed a far-UV circular dichroism spectrum characteristic of folded proteins, with alpha-helical and beta-sheet secondary structure. Its stable tertiary structure was confirmed by both tryptophan fluorescence and circular dichroism in the near UV. It proved heat stable up to 70 degrees C. Dynamic light scattering experiments revealed a unique population of particles averaging 4 nm in diameter, in good agreement with our model. Although these data suggest the successful creation of an artificial alpha/beta protein of more than 200 amino acids, Octarellin VI shows an apparent noncooperative chemical unfolding and low solubility. [less ▲]Detailed reference viewed: 15 (1 ULg)
Individual – to – resource landscape interaction strength can explain different collective feeding behaviours
; Delcourt, Johann
in PLoS ONE (2013), 8(10), 75879
Taking in sufficient quantities of nutrients is vital for all living beings and in doing so, individuals interact with the local resource environment. Here, we focus explicitly on the interactions between ... [more ▼]
Taking in sufficient quantities of nutrients is vital for all living beings and in doing so, individuals interact with the local resource environment. Here, we focus explicitly on the interactions between feeding individuals and the resource landscape. In particular, we are interested in the emergent movement dynamics resulting from these interactions. We present an individual-based simulation model for the movement of populations in a resource landscape that allows us to vary the strength of the interactions mentioned above. The key assumption and novelty of our model is that individuals can cause the release of additional nutrients, as well as consuming them. Our model produces clear predictions. For example, we expect more tortuous individual movement paths and higher levels of aggregation in populations occupying homogeneous environments where individual movement makes more nutrients available. We also show how observed movement dynamics could change when local nutrient sources are depleted or when the population density increases. Our predictions are testable and qualitatively reproduce the different feeding behaviours observed in filter-feeding ducks, for example. We suggest that considering two-way interactions between feeding individuals and resource landscapes could help to explain fine-scale movement dynamics. [less ▲]Detailed reference viewed: 29 (1 ULg)
Conditioned Medium from Bone marrow-derived Mesenchymal Stem Cells improves recovery after Spinal Cord Injury in rats: an original strategy to avoid cell transplantation.
CANTINIEAUX, Dorothée ; ; BLACHER, Silvia et al
in PLoS ONE (2013), 8(8), 69515
Spinal cord injury triggers irreversible loss of motor and sensory functions. Numerous strategies aiming at repairing the injured spinal cord have been studied. Among them, the use of bone marrow-derived ... [more ▼]
Spinal cord injury triggers irreversible loss of motor and sensory functions. Numerous strategies aiming at repairing the injured spinal cord have been studied. Among them, the use of bone marrow-derived mesenchymal stem cells (BMSCs) is promising. Indeed, these cells possess interesting properties to modulate CNS environment and allow axon regeneration and functional recovery. Unfortunately, BMSC survival and differentiation within the host spinal cord remain poor, and these cells have been found to have various adverse effects when grafted in other pathological contexts. Moreover, paracrine-mediated actions have been proposed to explain the beneficial effects of BMSC transplantation after spinal cord injury. We thus decided to deliver BMSC-released factors to spinal cord injured rats and to study, in parallel, their properties in vitro. We show that, in vitro, BMSC-conditioned medium (BMSC-CM) protects neurons from apoptosis, activates macrophages and is pro-angiogenic. In vivo, BMSC-CM administered after spinal cord contusion improves motor recovery. Histological analysis confirms the pro-angiogenic action of BMSC-CM, as well as a tissue protection effect. Finally, the characterization of BMSC-CM by cytokine array and ELISA identified trophic factors as well as cytokines likely involved in the beneficial observed effects. In conclusion, our results support the paracrine-mediated mode of action of BMSCs and raise the possibility to develop a cell-free therapeutic approach. [less ▲]Detailed reference viewed: 57 (11 ULg)
A new murine model of osteoblastic/osteolytic lesions from human androgen-resistant prostate cancer.
; ; et al
in PloS one (2013), 8(9), 75092
BACKGROUND: Up to 80% of patients dying from prostate carcinoma have developed bone metastases that are incurable. Castration is commonly used to treat prostate cancer. Although the disease initially ... [more ▼]
BACKGROUND: Up to 80% of patients dying from prostate carcinoma have developed bone metastases that are incurable. Castration is commonly used to treat prostate cancer. Although the disease initially responds to androgen blockade strategies, it often becomes castration-resistant (CRPC for Castration Resistant Prostate Cancer). Most of the murine models of mixed lesions derived from prostate cancer cells are androgen sensitive. Thus, we established a new model of CRPC (androgen receptor (AR) negative) that causes mixed lesions in bone. METHODS: PC3 and its derived new cell clone PC3c cells were directly injected into the tibiae of SCID male mice. Tumor growth was analyzed by radiography and histology. Direct effects of conditioned medium of both cell lines were tested on osteoclasts, osteoblasts and osteocytes. RESULTS: We found that PC3c cells induced mixed lesions 10 weeks after intratibial injection. In vitro, PC3c conditioned medium was able to stimulate tartrate resistant acid phosphatase (TRAP)-positive osteoclasts. Osteoprotegerin (OPG) and endothelin-1 (ET1) were highly expressed by PC3c while dikkopf-1 (DKK1) expression was decreased. Finally, PC3c highly expressed bone associated markers osteopontin (OPN), Runx2, alkaline phosphatase (ALP), bone sialoprotein (BSP) and produced mineralized matrix in vitro in osteogenic conditions. CONCLUSIONS: We have established a new CRPC cell line as a useful system for modeling human metastatic prostate cancer which presents the mixed phenotype of bone metastases that is commonly observed in prostate cancer patients with advanced disease. This model will help to understand androgen-independent mechanisms involved in the progression of prostate cancer in bone and provides a preclinical model for testing the effects of new treatments for bone metastases. [less ▲]Detailed reference viewed: 18 (0 ULg)
Functional Redundancy and Complementarities of Seed Dispersal by the Last Neotropical Megafrugivores
; ; et al
in PLoS ONE (2013), 8(2), 56252Detailed reference viewed: 24 (3 ULg)
Increased Cell Proliferation and Mucocyte Density in the Sea Anemone Aiptasia pallida Recovering from Bleaching
Fransolet, David ; Roberty, Stéphane ; et al
in PLoS ONE (2013), 8(5), 65015Detailed reference viewed: 26 (10 ULg)
Kinetics of IL-7 and IL-15 Levels after Allogeneic Peripheral Blood Stem Cell Transplantation following Nonmyeloablative Conditioning
; Fillet, Marianne ; Hannon, Muriel et al
in PLoS ONE (2013), 8(2), 55876
Background: We analysed kinetics of IL-7 and IL-15 levels in 70 patients given peripheral blood stem cells after nonmyeloablative conditioning. Methods: EDTA-anticoagulated plasma and serum samples were ... [more ▼]
Background: We analysed kinetics of IL-7 and IL-15 levels in 70 patients given peripheral blood stem cells after nonmyeloablative conditioning. Methods: EDTA-anticoagulated plasma and serum samples were obtained before conditioning and about once per week after transplantation until day 100. Samples were aliquoted and stored at 280uC within 3 hours after collection until measurement of cytokines. IL-7 and IL-15 levels were measured by ELISAs. Results: Median IL-7 plasma levels remained below 6 pg/L throughout the first 100 days, although IL-7 plasma levels were significantly higher on days 7 (5.1 pg/mL, P = 0.002), 14 (5.2 pg/mL, P,0.001), and 28 (5.1 pg/mL, P = 0.03) (but not thereafter) than before transplantation (median value of 3.8 pg/mL). Median IL-15 serum levels were significantly higher on days 7 (12.5 pg/mL, P,0.001), 14 (10.5 pg/mL, P,0.001), and 28 (6.2 pg/mL, P,0.001) than before transplantation (median value of 2.4 pg/mL). Importantly, IL-7 and IL-15 levels on days 7 or 14 after transplantation did not predict grade II–IV acute GVHD. Conclusions: These data suggest that IL-7 and IL-15 levels remain relatively low after nonmyeloablative transplantation, and that IL-7 and IL-15 levels early after nonmyeloablative transplantation do not predict for acute GVHD. [less ▲]Detailed reference viewed: 21 (8 ULg)
The stranding anomaly as population indicator: the case of harbour porpoise Phocoena phocoena in North-Western Europe.
; ; et al
in PloS one (2013), 8(4), 62180
Ecological indicators for monitoring strategies are expected to combine three major characteristics: ecological significance, statistical credibility, and cost-effectiveness. Strategies based on stranding ... [more ▼]
Ecological indicators for monitoring strategies are expected to combine three major characteristics: ecological significance, statistical credibility, and cost-effectiveness. Strategies based on stranding networks rank highly in cost-effectiveness, but their ecological significance and statistical credibility are disputed. Our present goal is to improve the value of stranding data as population indicator as part of monitoring strategies by constructing the spatial and temporal null hypothesis for strandings. The null hypothesis is defined as: small cetacean distribution and mortality are uniform in space and constant in time. We used a drift model to map stranding probabilities and predict stranding patterns of cetacean carcasses under H0 across the North Sea, the Channel and the Bay of Biscay, for the period 1990-2009. As the most common cetacean occurring in this area, we chose the harbour porpoise Phocoena phocoena for our modelling. The difference between these strandings expected under H0 and observed strandings is defined as the stranding anomaly. It constituted the stranding data series corrected for drift conditions. Seasonal decomposition of stranding anomaly suggested that drift conditions did not explain observed seasonal variations of porpoise strandings. Long-term stranding anomalies increased first in the southern North Sea, the Channel and Bay of Biscay coasts, and finally the eastern North Sea. The hypothesis of changes in porpoise distribution was consistent with local visual surveys, mostly SCANS surveys (1994 and 2005). This new indicator could be applied to cetacean populations across the world and more widely to marine megafauna. [less ▲]Detailed reference viewed: 18 (1 ULg)
Insight into the peopling of mainland southeast Asia from thai population genetic structure.
; ; Chaichoompu, Kridsadakorn et al
in PloS one (2013), 8(11), 79522
There is considerable ethno-linguistic and genetic variation among human populations in Asia, although tracing the origins of this diversity is complicated by migration events. Thailand is at the center ... [more ▼]
There is considerable ethno-linguistic and genetic variation among human populations in Asia, although tracing the origins of this diversity is complicated by migration events. Thailand is at the center of Mainland Southeast Asia (MSEA), a region within Asia that has not been extensively studied. Genetic substructure may exist in the Thai population, since waves of migration from southern China throughout its recent history may have contributed to substantial gene flow. Autosomal SNP data were collated for 438,503 markers from 992 Thai individuals. Using the available self-reported regional origin, four Thai subpopulations genetically distinct from each other and from other Asian populations were resolved by Neighbor-Joining analysis using a 41,569 marker subset. Using an independent Principal Components-based unsupervised clustering approach, four major MSEA subpopulations were resolved in which regional bias was apparent. A major ancestry component was common to these MSEA subpopulations and distinguishes them from other Asian subpopulations. On the other hand, these MSEA subpopulations were admixed with other ancestries, in particular one shared with Chinese. Subpopulation clustering using only Thai individuals and the complete marker set resolved four subpopulations, which are distributed differently across Thailand. A Sino-Thai subpopulation was concentrated in the Central region of Thailand, although this constituted a minority in an otherwise diverse region. Among the most highly differentiated markers which distinguish the Thai subpopulations, several map to regions known to affect phenotypic traits such as skin pigmentation and susceptibility to common diseases. The subpopulation patterns elucidated have important implications for evolutionary and medical genetics. The subpopulation structure within Thailand may reflect the contributions of different migrants throughout the history of MSEA. The information will also be important for genetic association studies to account for population-structure confounding effects. [less ▲]Detailed reference viewed: 18 (5 ULg)
A new method for in vitro detection of bromodeoxyuridine in serum: a proof of concept in a songbird species, the canary.
; ; et al
in PloS one (2013), 8(5), 63692
Systemic injection of a thymidine analogue such as bromodeoxyuridine (BrdU) in vertebrates is commonly used to detect and study cell production during development, adulthood, and pathology, particularly ... [more ▼]
Systemic injection of a thymidine analogue such as bromodeoxyuridine (BrdU) in vertebrates is commonly used to detect and study cell production during development, adulthood, and pathology, particularly in studies of adult neurogenesis. Although researchers are applying this technique to multiple species in various physiological conditions, the rate of BrdU clearance from the serum remains unknown in most cases. Changes in this clearance rate as a function of the species, sex or endocrine condition could however profoundly affect the interpretation of the results. We describe a rapid, sensitive, but simple bioassay for post-injection detection and quantification of BrdU in serum. This procedure was shown to be suitable for determining the length of time a thymidine analogue remains in the bloodstream of one avian species and seems applicable to any vertebrate provided sufficiently large blood samples can be collected. This technique was used to demonstrate that, in canaries, BrdU injected at a dose of 100 mg/kg is no longer available for incorporation into DNA between 30 and 60 min post-injection, a delay shorter than anticipated based on the available literature. Preliminary data suggest a similar fast clearance in Japanese quail and mice. [less ▲]Detailed reference viewed: 5 (0 ULg)
The proline-rich motif of the proDer p 3 allergen propeptide is crucial for protease-protease interaction.
Dumez, Marie-Eve ; ; Campisi, Vincenzo et al
in PloS one (2013), 8(9), 68014
The majority of proteases are synthesized in an inactive form, termed zymogen, which consists of a propeptide and a protease domain. The propeptide is commonly involved in the correct folding and specific ... [more ▼]
The majority of proteases are synthesized in an inactive form, termed zymogen, which consists of a propeptide and a protease domain. The propeptide is commonly involved in the correct folding and specific inhibition of the enzyme. The propeptide of the house dust mite allergen Der p 3, NPILPASPNAT, contains a proline-rich motif (PRM), which is unusual for a trypsin-like protease. By truncating the propeptide or replacing one or all of the prolines in the non-glycosylated zymogen with alanine(s), we demonstrated that the full-length propeptide is not required for correct folding and thermal stability and that the PRM is important for the resistance of proDer p 3 to undesired proteolysis when the protein is expressed in Pichia pastoris. Additionally, we followed the maturation time course of proDer p 3 by coupling a quenched-flow assay to mass spectrometry analysis. This approach allowed to monitor the evolution of the different species and to determine the steady-state kinetic parameters for activation of the zymogen by the major allergen Der p 1. This experiment demonstrated that prolines 5 and 8 are crucial for proDer p 3-Der p 1 interaction and for activation of the zymogen. [less ▲]Detailed reference viewed: 25 (10 ULg)
Proteomic characterization of murid herpesvirus 4 extracellular virions.
Vidick, Sarah ; ; Gonon Rodrigues Palmeira, Leonor et al
in PloS one (2013), 8(12), 83842
Gammaherpesvirinae, such as the human Epstein-Barr virus (EBV) and the Kaposi's sarcoma associated herpesvirus (KSHV) are highly prevalent pathogens that have been associated with several neoplastic ... [more ▼]
Gammaherpesvirinae, such as the human Epstein-Barr virus (EBV) and the Kaposi's sarcoma associated herpesvirus (KSHV) are highly prevalent pathogens that have been associated with several neoplastic diseases. As EBV and KSHV are host-range specific and replicate poorly in vitro, animal counterparts such as Murid herpesvirus-4 (MuHV-4) have been widely used as models. In this study, we used MuHV-4 in order to improve the knowledge about proteins that compose gammaherpesviruses virions. To this end, MuHV-4 extracellular virions were isolated and structural proteins were identified using liquid chromatography tandem mass spectrometry-based proteomic approaches. These analyses allowed the identification of 31 structural proteins encoded by the MuHV-4 genome which were classified as capsid (8), envelope (9), tegument (13) and unclassified (1) structural proteins. In addition, we estimated the relative abundance of the identified proteins in MuHV-4 virions by using exponentially modified protein abundance index analyses. In parallel, several host proteins were found in purified MuHV-4 virions including Annexin A2. Although Annexin A2 has previously been detected in different virions from various families, its role in the virion remains controversial. Interestingly, despite its relatively high abundance in virions, Annexin A2 was not essential for the growth of MuHV-4 in vitro. Altogether, these results extend previous work aimed at determining the composition of gammaherpesvirus virions and provide novel insights for understanding MuHV-4 biology. [less ▲]Detailed reference viewed: 12 (3 ULg)