Pathogenesis of human metapneumovirus lung infection in BALB/c mice and cotton rats

Human metapneumovirus (hMPV) is a newly described member of the Paramyxoviridae family causing acute respiratory tract infections, especially in young children. We studied the pathogenesis of this viral infection in two experimental small animal models (BALB/c mice and cotton rats). Significant viral replication in the lungs of both animals was found following an intranasal challenge of 10(8) 50% tissue culture infectious doses (TCID50) and persisted for <2 and <3 weeks in the case of cotton rats and mice, respectively. Peak viral loads were found on day 5 postinfection in both mice (mean of 1.92 x 10(7) TCID50/g lung) and cotton rats (mean of 1.03 x 10(5) TCID50/g). Clinical symptoms consisting of breathing difficulties, ruffled fur, and weight loss were noted in mice only around the time of peak viral replication. Most significant pulmonary inflammatory changes and peak expression of macrophage inflammatory protein 1alpha, gamma interferon, and RANTES occurred at the time of maximal viral replication (day 5) in both models. Cellular infiltration occurred predominantly around and within alveoli and persisted for at least 21 days in mice, whereas it was more limited in time with more peribronchiolitis in cotton rats. Both animal models would be of great value in evaluating different therapeutic agents, as well as vaccine candidates against hMPV.     

Telomeric transgenes and trans-silencing in Drosophila

Autonomous P elements, inserted in heterochromatic telomeric associated sequences (TAS) at the X chromosome telomere (site 1A) have strong P element regulatory properties that include repression of P-induced hybrid-dysgenesis and of P-lacZ expression in the germline. P-lacZ insertions or defective P elements at 1A in TAS can also repress in trans a euchromatic P-lacZ in the germline. This property has been called a trans-silencing effect (TSE). It requires some sequence-homology between the telomeric insertion and the euchromatic transgene. When repression is partial, variegating lacZ expression is observed, suggesting a chromatin-based component. TSE is observed only when the silencer transgenes are maternally inherited and occurs only in the female germline. We have evidence that this silencing also works in the presence of homologous non-P element sequences suggesting that homology-dependent silencing could be a general phenomenon in the female germline; such a system might have been subsequently adopted by the P element family, allowing its own repression.     

Can Wide Consultation Help with Setting Priorities for Large-Scale Biodiversity Monitoring Programs?

Climate and other global change phenomena affecting biodiversity require monitoring to track ecosystem changes and guide policy and management actions. Designing a biodiversity monitoring program is a difficult task that requires making decisions that often lack consensus due to budgetary constrains. As monitoring programs require long-term investment, they also require strong and continuing support from all interested parties. As such, stakeholder consultation is key to identify priorities and make sound design decisions that have as much support as possible. Here, we present the results of a consultation conducted to serve as an aid for designing a large-scale biodiversity monitoring program for the province of Québec (Canada). The consultation took the form of a survey with 13 discrete choices involving tradeoffs in respect to design priorities and 10 demographic questions (e.g., age, profession). The survey was sent to thousands of individuals having expected interests and knowledge about biodiversity and was completed by 621 participants. Overall, consensuses were few and it appeared difficult to create a design fulfilling the priorities of the majority. Most participants wanted 1) a monitoring design covering the entire territory and focusing on natural habitats; 2) a focus on species related to ecosystem services, on threatened and on invasive species. The only demographic characteristic that was related to the type of prioritization was the declared level of knowledge in biodiversity (null to high), but even then the influence was quite small.     

CD44 Plays a Functional Role in Helicobacter pylori-induced Epithelial Cell Proliferation

The cytotoxin-associated gene (Cag) pathogenicity island is a strain-specificconstituent of Helicobacter pylori (H. pylori) thataugments cancer risk. CagA translocates into the cytoplasm where it stimulates cellsignaling through the interaction with tyrosine kinase c-Met receptor, leadingcellular proliferation. Identified as a potential gastric stem cell marker,cluster-of-differentiation (CD) CD44 also acts as a co-receptor for c-Met, butwhether it plays a functional role in H. pylori-induced epithelialproliferation is unknown. We tested the hypothesis that CD44 plays a functional rolein H. pylori-induced epithelial cell proliferation. To assay changesin gastric epithelial cell proliferation in relation to the direct interaction withH. pylori, human- and mouse-derived gastric organoids wereinfected with the G27 H. pylori strain or a mutant G27 strainbearing cagA deletion (∆CagA::cat). Epithelial proliferationwas quantified by EdU immunostaining. Phosphorylation of c-Met was analyzed byimmunoprecipitation followed by Western blot analysis for expression of CD44 andCagA. H. pylori infection of both mouse- and human-derived gastricorganoids induced epithelial proliferation that correlated with c-Metphosphorylation. CagA and CD44 co-immunoprecipitated with phosphorylated c-Met. Theformation of this complex did not occur in organoids infected with∆CagA::cat. Epithelial proliferation in response toH. pylori infection was lost in infected organoids derived fromCD44-deficient mouse stomachs. Human-derived fundic gastric organoids exhibited aninduction in proliferation when infected with H. pylorithat was notseen in organoids pre-treated with a peptide inhibitor specific to CD44. In thewell-established Mongolian gerbil model of gastric cancer, animals treated with CD44peptide inhibitor Pep1, resulted in the inhibition of H.pylori-induced proliferation and associated atrophic gastritis. The currentstudy reports a unique approach to study H. pylori interaction withthe human gastric epithelium. Here, we show that CD44 plays a functional role inH. pylori-induced epithelial cell proliferation.     

Both TRIF and IPS-1 Adaptor Proteins Contribute to the Cerebral Innate Immune Response against Herpes Simplex Virus 1 Infection

Toll-like receptors (TLRs) and RNA helicases (RLHs) are important cell sensors involved in the immunological control of viral infections through production of type I interferon (IFN). The impact of a deficiency in the TRIF and IPS-1 adaptor proteins, respectively, implicated in TLR3 and RLH signaling pathways, was investigated during herpes simplex virus 1 (HSV-1) encephalitis. TRIF^−/−, IPS-1^−/−, and C57BL/6 wild-type (WT) mice were infected intranasally with 7.5 × 10⁵ PFU of HSV-1. Mice were monitored for neurological signs and survival over 20 days. Groups of mice were sacrificed on days 3, 5, 7, 9, and 11 postinfection for determination of brain viral replication by quantitative PCR (qPCR), plaque assay, and immunohistochemistry and for alpha/beta interferon (IFN-α/β) levels and phosphorylation of interferon regulatory factors 3 and 7 (IRF-3 and -7) in brain homogenates by enzyme-linked immunosorbent assay (ELISA) and Western blotting, respectively. TRIF^−/− and IPS-1^−/− mice had higher mortality rates than WT mice (P = 0.02 and P = 0.09, respectively). Viral antigens were more disseminated throughout the brain, correlating with a significant increase in brain viral load for TRIF^−/− (days 5 to 9) and IPS-1^−/− (days 7 and 9) mice compared to results for the WT. IFN-β production was reduced in brain homogenates of TRIF^−/− and IPS-1^−/− mice on day 5 compared to results for the WT, whereas IFN-α levels were increased on day 7 in TRIF^−/− mice. Phosphorylation levels of IRF-3 and IRF-7 were decreased in TRIF^−/− and IPS-1^−/− mice, respectively. These data suggest that both the TRIF and IPS-1 signaling pathways are important for the control of HSV replication in the brain and survival through IFN-β production.     

Betaine use by rhizosphere bacteria: genes essential for trigonelline, stachydrine, and carnitine catabolism in Rhizobium meliloti are located on pSym in the symbiotic region.

Rhizobium meliloti is known to use betaines synthesized by its host, Medicago sativa, as osmoprotectants and sources of energy. It is shown in the present report that the symbiotic megaplasmid (pSym) of R. meliloti RCR2011 encodes functions essential to the catabolism of three betaines, trigonelline (nicotinic acid N-methylbetaine), stachydrine (proline betaine or dimethylproline), and carnitine (gamma-trimethyl-beta-hydroxybutyrobetaine). Preliminary evidence is presented showing that functions on pSym also influence the catabolism of choline and its oxidative product, glycine betaine. Genes implicated in betaine catabolism are found in the symbiotic region of pSym. Trigonelline catabolism functions lie between two clusters of symbiotic genes, nifKDH and nok/fixVI'. Stachydrine and carnitine functions lie to the right of trigonelline catabolism functions, immediately to the right of fixVI'. Information necessary to choline and glycine betaine catabolism is probably encoded to the right of stachydrine catabolism functions.     

Laboratory rearing ofAnaphes sordidatus [Hym.: Mymaridae] on carrot weevil eggs [Col.: Curculionidae]

A technique for rearingAnaphes sordidatus (Girault) on eggs of laboratory-reared carrot weevil,Listronotus oregonensis (Le Conte), is described. Individual rearing was possible by using polyethylene embedding capsules that enabled easy manipulation of parasitized carrot weevil eggs for use in subsequent experimental procedures. The technique described resulted in 65% parasitization of carrot weevil eggs and 90 mn per day were sufficient to obtainca. 200 parasites daily.      

Inherited haemolytic anaemia created by insertional inactivation of the α-spectrin gene

In the process of generating transgenic mice, inserted foreign DNA can cause insertional inactivation of the flanking genetic locus and simultaneously provide a molecular tag for localizing and cloning the inactivated gene. We describe the case of an insertional mutation leading, in animals homozygous for the insertion, to severe anaemia that was lethal within a few days after birth. The haemolytic anaemia and microspherocytosis of the red cells strongly suggested membrane abnormalities of the erythrocytes. Byin situ localization of the integration site, protein analysis of the red cell membranes, northern and Southern blot analyses, we were able to demonstrate that the integrated transgene had affected the α-spectrin gene locus.