A comparison of statistical models for short categorical or ordinal time series with applications in ecology

We study two statistical models for short-length categorical (or ordinal) time series. The first one is a regression model based on generalized linear model. The second one is a parametrized Markovian model, particularizing the discrete autoregressive model to the case of categorical data. These models are used to analyze two data-sets: annual larch cone production and weekly planktonic abundance.Comment: 18 page

Long Lasting Persistence of Bacillus thuringiensis Subsp. israelensis (Bti) in Mosquito Natural Habitats

Background: The detrimental effects of chemical insecticides on the environment and human health have lead to the call for biological alternatives. Today, one of the most promising solutions is the use of spray formulations based on Bacillus thuringiensis subsp. israelensis (Bti) in insect control programs. As a result, the amounts of Bti spread in the environment are expected to increase worldwide, whilst the common belief that commercial Bti is easily cleared from the ecosystem has not yet been clearly established. Methodology/Main Findings: In this study, we aimed to determine the nature and origin of the high toxicity toward mosquito larvae found in decaying leaf litter collected in several natural mosquito breeding sites in the Rhône-Alpes region. From the toxic fraction of the leaf litter, we isolated B. cereus-like bacteria that were further characterized as B. thuringiensis subsp. israelensis using PCR amplification of specific toxin genes. Immunological analysis of these Bti strains showed that they belong to the H14 group. We finally used amplified length polymorphism (AFLP) markers to show that the strains isolated from the leaf litter were closely related to those present in the commercial insecticide used for field application, and differed from natural worldwide genotypes. Conclusions/Significance: Our results raise the issue of the persistence, potential proliferation and environmental accumulation of human-spread Bti in natural mosquito habitats. Such Bti environmental persistence may lengthen th

Overexpression of a Minimal Domain of Calpastatin Suppresses IL-6 Production and Th17 Development via Reduced NF-κB and Increased STAT5 Signals

Calpain, a calcium-dependent cysteine protease, is reportedly involved in the pathophysiology of autoimmune diseases such as rheumatoid arthritis (RA). In addition, autoantibodies against calpastatin, a natural and specific inhibitor of calpain, are widely observed in RA. We previously reported that E-64-d, a membrane-permeable cysteine protease inhibitor, is effective in treating experimental arthritis. However, the exact role of the calpastatin-calpain balance in primary inflammatory cells remains unclear. Here we investigated the effect of calpain-specific inhibition by overexpressing a minimal functional domain of calpastatin in primary helper T (Th) cells, primary fibroblasts from RA patients, and fibroblast cell lines. We found that the calpastatin-calpain balance varied during Th1, Th2, and Th17 development, and that overexpression of a minimal domain of calpastatin (by retroviral gene transduction) or the inhibition of calpain by E-64-d suppressed the production of IL-6 and IL-17 by Th cells and the production of IL-6 by fibroblasts. These suppressions were associated with reductions in RORγt expression and STAT3 phosphorylation. Furthermore, inhibiting calpain by silencing its small regulatory subunit (CPNS) suppressed Th17 development. We also confirmed that overexpressing a minimal domain of calpastatin suppressed IL-6 by reducing NF-κB signaling via the stabilization of IκBα, without affecting the upstream signal. Moreover, our findings indicated that calpastatin overexpression suppressed IL-17 production by Th cells by up-regulating the STAT5 signal. Finally, overexpression of a minimal domain of calpastatin suppressed IL-6 production efficiently in primary fibroblasts derived from the RA synovium. These findings suggest that inhibiting calpain by overexpressing a minimal domain of calpastatin could coordinately suppress proinflammatory activities, not only those of Th cells but also of synovial fibroblasts. Thus, this strategy may prove viable as a candidate treatment for inflammatory diseases such as RA

Histoire evolutive des schistosomes. Phylogenies moleculaires: coevolution et capture d'hotes. Modele de fixation de la gonochorie

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : TD 81125 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Data from: Identifying insecticide resistance genes in mosquito by combining AFLP genome scan and 454 pyrosequencing

AFLP-based genome scans are widely used to study the genetics of adaptation and to identify genomic regions potentially under selection. However, this approach usually fails to detect the actual genes or mutations targeted by selection due to the difficulty to obtain the sequences from AFLP fragments. Here we combine classical AFLP outlier detection to 454 sequencing of AFLP fragments obtained from chosen individuals to obtain the sequence of outliers. We applied this approach to the study of resistance to Bacillus thuringiensis israelensis (Bti) toxins in the dengue vector Aedes aegypti. A genome scan of Bti-resistant and Bti-susceptible Aedes aegypti laboratory strains was performed based on 432 AFLP markers. Fourteen outliers were detected using two different population genetics algorithms, a frequentist and a Bayesian approach. Out of these, 11 were successfully sequenced. Three contained transposable elements (TEs) sequences. The 10 outliers that could be mapped at a unique location in the reference genome were located on different supercontigs, underlying the multigenic basis of resistance to Bti toxins. One outlier was in the vicinity of a gene coding for an aminopeptidase potentially involved in Bti toxin binding. Patterns of sequence variability of this gene showed significant deviation from neutrality in the resistant strain but not in the susceptible strain, even after taking into account the known demographic history of the selected strain. This gene is a promising candidate for future functional analysis

454 AFLP fragments sequencing

454 complete (CR) and incomplete reads (IR) for 22 AFLP profiles of susceptible individuals (Bora-Bora strain: Ae) and Bti resistant individuals (LiTOX strain

The Evolution of Dimorphism and Separate Sexes in Schistosomes

International audienceThe fixation of gonochorism (separate sexes) from an hermaphrodite ancestor in the Schistosomatidae may have been the result of selection for dimorphism, under the particular constraint of having to expel eggs from the vertebrate circulatory system. The hermaphroditic system, which exists in blood parasites closely related to Schistosomatidae, e.g. Spirorchidae and Sanguinicolidae, may result from a weaker constraint caused by the different pathways of egg output, and a weaker aggregation of parasites in the host population that will act against the fixation of gonochorism. The importance of these two factors relative to two others (inbreeding depression and allocation to female function in hermaphrodites) in the evolution of gonochorism in blood parasites is evaluated using an analytical model

Sequences of a candidate gene for Bti resistance in Aedes aegypti

Batch of aligned sequences (Sanger) of exon 2 (1004 bp) of puromycin-sensitive aminopeptidase (AAEL012918) from 11 susceptible individuals (Bora-Bora strain) and 12 Bti-resistant individuals (LiTOX strain

AFLP Profiles

AFLP profile