Differential cytopathogenesis of respiratory syncytial virus prototypic and clinical isolates in primary pediatric bronchial epithelial cells

<p>Abstract</p> <p>Background</p> <p>Human respiratory syncytial virus (RSV) causes severe respiratory disease in infants. Airway epithelial cells are the principle targets of RSV infection. However, the mechanisms by which it causes disease are poorly understood. Most RSV pathogenesis data are derived using laboratory-adapted prototypic strains. We hypothesized that such strains may be poorly representative of recent clinical isolates in terms of virus/host interactions in primary human bronchial epithelial cells (PBECs).</p> <p>Methods</p> <p>To address this hypothesis, we isolated three RSV strains from infants hospitalized with bronchiolitis and compared them with the prototypic RSV A2 in terms of cytopathology, virus growth kinetics and chemokine secretion in infected PBEC monolayers.</p> <p>Results</p> <p>RSV A2 rapidly obliterated the PBECs, whereas the clinical isolates caused much less cytopathology. Concomitantly, RSV A2 also grew faster and to higher titers in PBECs. Furthermore, dramatically increased secretion of IP-10 and RANTES was evident following A2 infection compared with the clinical isolates.</p> <p>Conclusions</p> <p>The prototypic RSV strain A2 is poorly representative of recent clinical isolates in terms of cytopathogenicity, viral growth kinetics and pro-inflammatory responses induced following infection of PBEC monolayers. Thus, the choice of RSV strain may have important implications for future RSV pathogenesis studies.</p

Landscape potential in pollen provisioning for beneficial insects favours biological control in crop fields

International audienceThe importance of landscape complexity for biological control is well-known, but its functional roles are poorly understood. Objectives We evaluated the landscape capacity to provide floral resources for beneficial insects and its consequences for biological control in fields. Methods The gut contents of adult hoverflies sampled in 41 cereal fields were analysed to determine which plant species are exploited. The relative value of each habitat in providing adequate pollen resources was evaluated by vegetation survey. Then 15 cereal fields were selected along a gradient of landscape complexity, where the abundance of aphids, hoverfly larvae and aphid parasitism was monitored. The proportion of each habitat in landscape buffers surrounding these fields was calculated and used to assess the potential level of pollen resources provision (LP index). Results Aphid abundance significantly decreased with an increase of the LP index mainly sustained by grassy strips and weeds in fields. However, hoverfly larvae abundance also decreased with the increasing LP index. The enhancement of the aphid parasitism rate with the LP index suggests that aphid parasitoids may benefit from the same floral resources as hoverflies. Their crop habitat specialism may give them a competitive advantage in crop fields where both aphid and floral resources are abundant. Conclusions Complex interaction networks involved in biological control may disrupt the expected direct effects of floral resource provisioning for a focal beneficial species. We highlighted two habitats provisioning floral resources for which the LP index could be very helpful to optimize management strategies to improve biological control

Procedures and protocol for soil biodiversity monitoring: “RMQS-Biodiv”, a French Pilot area experience

International audienc

Relevance of different soil fauna and microflora groups in the monitoring of soil biodiversity: RMQS-Biodiv, a french Pilote area experience

affiche, résuméSoil biota play essential roles in delivering key ecosystem goods and services, and are both directly and indirectly responsible for acting in many important functions (nutrient release, soil structure maintain, contribution to water storage). It is thus essential to characterize both the species diversity and the biological functions. In order to monitor soil biodiversity (species and function) in relation to land use (mainly agricultural practices) and pedoclimatic parameters, a French program « RMQS-biodiv » was developed at a wide regional scale (Brittany). An important national research collaboration (12 research teams) supported the program, that undertook the study of several biological parameters such as macrofauna diversity (earthworms, total macro-invertebrates), mesofauna diversity (acarina and collembola), microorganisms (nematodes diversity, microbial biomass, bacterial and fungal diversity), as well as functional biological parameters (soil respiration, humus index, macrofauna and mesofauna activity: biogenic structure, feeding activity). This program was connected to a larger soil monitoring network developed at national scale (Soil Quality Measurement Network- RMQS) which monitored soil parameters (chemistry, physic) and agricultural management using a regular grid (16 X 16 km) covering the whole national territory. The link between these two programs allowed the study of biological parameters in the light of soil and agricultural characteristics, and thus the definition of biological indicators. The results obtained from the analysis of 115 sites sampled in 2006 and 2007, will be discussed in terms of relevance of these biological criteria as indicators, and in fine of their transfer to field actors (technicians) who are in charge of new tool implementation on agronomical management assistance. Furthermore, the results will also be discussed with respect to propositions and recommendations made by the ENVASSO project (Environmental Assessment of Soil for Monitoring), especially the biological criteria proposed by the European project and the hierarchy of these criteria

Cytopathogenesis of Sendai Virus in Well-Differentiated Primary Pediatric Bronchial Epithelial Cells ▿ †

Sendai virus (SeV) is a murine respiratory virus of considerable interest as a gene therapy or vaccine vector, as it is considered nonpathogenic in humans. However, little is known about its interaction with the human respiratory tract. To address this, we developed a model of respiratory virus infection based on well-differentiated primary pediatric bronchial epithelial cells (WD-PBECs). These physiologically authentic cultures are comprised of polarized pseudostratified multilayered epithelium containing ciliated, goblet, and basal cells and intact tight junctions. To facilitate our studies, we rescued a replication-competent recombinant SeV expressing enhanced green fluorescent protein (rSeV/eGFP). rSeV/eGFP infected WD-PBECs efficiently and progressively and was restricted to ciliated and nonciliated cells, not goblet cells, on the apical surface. Considerable cytopathology was evident in the rSeV/eGFP-infected cultures postinfection. This manifested itself by ciliostasis, cell sloughing, apoptosis, and extensive degeneration of WD-PBEC cultures. Syncytia were also evident, along with significant basolateral secretion of proinflammatory chemokines, including IP-10, RANTES, tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), interleukin 6 (IL-6), and IL-8. Such deleterious responses are difficult to reconcile with a lack of pathogenesis in humans and suggest that caution may be required in exploiting replication-competent SeV as a vaccine vector. Alternatively, such robust responses might constitute appropriate normal host responses to viral infection and be a prerequisite for the induction of efficient immune responses

Etude de bioindicateurs en fonction de l’occupation d’un sol agricole haut-normand

National audienc

Les indicateurs de l'état biologique des sols : Guide de sélection selon le type d’application et/ou la problématique

National audienc

Soil bioindicators: how soil properties influence their responses and to select them in function of the site issues?

International audienc

Soil bioindicators: how to select them in function of the site issues?

International audienc